Download TABLE OF CONTENTS

TABLE OF CONTENTS
1.0
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
1.1
1.2
SYSTEM COVERAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
SIX-STEP TROUBLESHOOTING PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . . .1
2.0
IDENTIFICATION OF SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
3.0
SYSTEM DESCRIPTION AND FUNCTIONAL OPERATION . . . . . . . . . . . . . . . . . . . . . .1
3.1
3.2
3.3
3.4
3.5
4.0
SYSTEM COMPONENT LOCATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
4.1
4.2
4.3
4.4
4.5
4.6
4.7
5.0
GENERAL DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
JTEC + CONTROLLER AND OPERATING MODES . . . . . . . . . . . . . . . . . . . . . .1
3.2.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
3.2.2 Hardware Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
3.2.3 Software Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
3.2.4 Spark Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
3.2.5 Fuel Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2
3.2.6 On Board Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
3.2.7 Transmission Control (4.0L - XJ Body Only) . . . . . . . . . . . . . . . . . . . . . . .3
3.2.8 Other Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3
3.2.9 PCM Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4
3.2.10 Non-Monitored Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5
3.2.11 SKIS OVERVIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
3.2.12 SKIS OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6
DIAGNOSTIC TROUBLE CODES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.3.1 Hard Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.3.2 Intermittent Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.3.3 Reset Counter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
3.3.4 Handling No Trouble Code Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
USING THE DRBIIIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7
DRBIIIT ERROR MESSAGES AND BLANK SCREEN . . . . . . . . . . . . . . . . . . . . .8
3.5.1 DRBIIIT Does Not Power Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
3.5.2 Display Is Not Visible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8
POWERTRAIN CONTROL MODULE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .9
CONTROLS & SOLENOIDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
DATA LINK CONNECTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
SENSORS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
FUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
RELAYS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
SWITCHES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21
DISCLAIMERS, SAFETY, WARNINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.1
5.2
5.3
DISCLAIMERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
SAFETY AND WARNINGS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2.1 Technician Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2.2 Vehicle Preparation for Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2.3 Servicing Sub-Assemblies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
5.2.4 DRBIIIT Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
WARNINGS AND CAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
5.3.1 Vehicle Damage Warnings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
5.3.2 Road Testing a Complaint Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
i
TABLE OF CONTENTS - Continued
7.0
DIAGNOSTIC INFORMATION AND PROCEDURES . . . . . . . . . . . . . . . . . . . . . . . . . . .25
7.1
GENERAL TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
TROUBLE CODE TEST
DTC TEST
CHECKING THE SYSTEM FOR DIAGNOSTIC TROUBLE CODES .26
TROUBLE CODE TESTS
TC-1A REPAIRING - NO CAM SIGNAL AT PCM . . . . . . . . . . . . . . . . . . . . . .28
TC-5A REPAIRING - CHARGING SYSTEM VOLTAGE TOO LOW . . . . . . . .36
TC-6A REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH . . . . . . .42
TC-10A REPAIRING - AUTO SHUTDOWN RELAY CONTROL CIRCUIT . . . .50
TC-11A REPAIRING - GENERATOR FIELD NOT SWITCHING PROPERLY .54
TC-12A REPAIRING TORQUE CONVERTER CLUTCH/TRANS RELAY CKT
(TJ/XJ BODY WITH 3SPD AUTO TRANS) . . . . . . . . . . . . . . . . . . . . .58
TC-14A REPAIRING - RADIATOR FAN RELAY CIRCUIT . . . . . . . . . . . . . . . .60
TC-15A REPAIRING - SPEED CONTROL CIRCUITS . . . . . . . . . . . . . . . . . . .64
TC-16A REPAIRING - A/C CLUTCH RELAY CIRCUIT. . . . . . . . . . . . . . . . . . .72
TC-18A REPAIRING - EVAP PURGE SOLENOID CIRCUIT . . . . . . . . . . . . . .76
TC-19A REPAIRING - INJECTOR #3 CONTROL CIRCUIT . . . . . . . . . . . . . . .82
TC-20A REPAIRING - INJECTOR #2 CONTROL CIRCUIT . . . . . . . . . . . . . . .84
TC-21A REPAIRING - INJECTOR CONTROL CIRCUITS . . . . . . . . . . . . . . . .86
TC-25A REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS . . . . . . . . . .92
TC-26A REPAIRING - THROTTLE POSITION SENSOR VOLTAGE LOW . .108
TC-27A REPAIRING - THROTTLE POSITION SENSOR VOLTAGE HIGH . .112
TC-30A REPAIRING - ECT SENSOR VOLTAGE TOO LOW . . . . . . . . . . . . .116
TC-31A REPAIRING - ECT SENSOR VOLTAGE TOO HIGH . . . . . . . . . . . .120
TC-35A REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL . . . . . . . . .124
TC-36A REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO
MAP SENSOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
TC-37A REPAIRING - MAP SENSOR VOLTAGE TOO HIGH . . . . . . . . . . . .140
TC-39A REPAIRING - NO CHANGE IN MAP FROM START TO RUN . . . . .146
TC-40A REPAIRING - NO CRANK REFERENCE SIGNAL AT PCM . . . . . . .150
TC-43A REPAIRING - IGNITION COIL #1 PRIMARY CIRCUIT. . . . . . . . . . .156
TC-44A REPAIRING - NO ASD RELAY OUTPUT VOLTAGE AT PCM . . . . .160
TC-49A REPAIRING - PCM FAILURE EEPROM WRITE DENIED . . . . . . . .164
TC-57A REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE LOW . . . . .166
TC-58A REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE HIGH . . . . .170
TC-61A REPAIRING - INJECTOR #4 CONTROL CIRCUIT . . . . . . . . . . . . . .174
TC-62A REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE. . . . . . . .176
TC-69A REPAIRING - INJECTOR #5 CONTROL CIRCUIT . . . . . . . . . . . . . .182
TC-70A REPAIRING - INJECTOR #6 CONTROL CIRCUIT . . . . . . . . . . . . . .184
TC-82A REPAIRING - SPEED CONTROL POWER RELAY OR SPEED
CONTROL 12V DRIVER CIRCUIT. . . . . . . . . . . . . . . . . . . . . . . . . . .186
TC-86A REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH. . . . . . .194
TC-87A REPAIRING - SPEED CONTROL SWITCH ALWAYS LOW . . . . . . .200
TC-101A REPAIRING - FUEL PUMP (SYSTEM) RELAY CONTROL
CIRCUIT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202
TC-114A REPAIRING - P/N SWITCH STUCK IN PARK OR GEAR . . . . . . . .206
TC-115A REPAIRING - POWER STEERING SWITCH FAILURE . . . . . . . . . .212
TC-118A REPAIRING - FUEL SYSTEM RICH 1/1 RICH . . . . . . . . . . . . . . . . .218
TC-119A REPAIRING - FUEL SYSTEM LEAN 1/1 LEAN . . . . . . . . . . . . . . . .222
TC-126A REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE. . . . . . . .226
ii
TABLE OF CONTENTS - Continued
TC-132A REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP. . . .232
TC-148A REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT
LOCK-UP (TJ/XJ BODY WITH 3 SPD AUTO TRANS) . . . . . . . . . . .238
TC-149A REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO LOW . . .244
TC-150A REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH . .248
TC-151A REPAIRING - FUEL LEVEL SENDING UNIT NO CHANGE OVER
TIME. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .254
TC-153A REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO
HIGH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .258
TC-155A REPAIRING - 1/1 O2 SENSOR SHORTED TO GROUND . . . . . . . .264
TC-156A REPAIRING - 1/2 O2 SENSOR SHORTED TO GROUND . . . . . . . .268
TC-157A REPAIRING - INTERMITTENT LOSS OF CMP OR CKP . . . . . . . . .272
TC-225A REPAIRING - NO CDD BUS MESSAGE FROM THE MIC. . . . . . . .284
TC-226A REPAIRING - NO CCD BUS MESSAGE RECEIVED FROM SKIM .288
TC-232A REPAIRING - INVALID OR WRONG KEY MESSAGE FROM
SKIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .292
TC-235A REPAIRING - OIL PRESSURE SENSOR LOW EXCEEDED . . . . . .296
TC-236A REPAIRING OIL PRESSURE SENSOR HIGH EXCEEDED. . . . . . .300
SENTRY
SK-1A
SK-2A
SK-3A
SK-4A
SK-5A
SK-6A
SK-7A
SK-8A
SK-9A
KEY IMMOBILIZER SYSTEM
IDENTIFYING SENTRY KEY IMMOBILIZER SYSTEM . . . . . . . . . .306
REPAIRING - PCM STATUS FAILURE . . . . . . . . . . . . . . . . . . . . . . .310
REPAIRING - ROLLING CODE FAILURE . . . . . . . . . . . . . . . . . . . . .314
REPAIRING - SERIAL LINK EXTERNAL FAILURE. . . . . . . . . . . . . .318
REPAIRING - TRANSPONDER COMMUNICATION FAILURE. . . . .322
REPAIRING - TRANSPONDER CRC (CYCLIC REDUNDANCY
CHECK) FAILURE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .326
REPAIRING - TRANSPONDER ID MISMATCH . . . . . . . . . . . . . . . .330
REPAIRING - TRANSPONDER RESPONSE MISMATCH . . . . . . . .334
REPAIRING - VIN MISMATCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .338
NO TROUBLE CODE TESTS
NTC-1A NO TROUBLE CODE TEST MENU . . . . . . . . . . . . . . . . . . . . . . . . . .342
NTC-2A CHECKING SECONDARY IGNITION AND TIMING . . . . . . . . . . . . .344
NTC-3A CHECKING - THE PCM POWER AND GROUND CIRCUITS . . . . .346
NTC-4A CHECKING THE ENGINE VACUUM . . . . . . . . . . . . . . . . . . . . . . . . .348
NTC-5A CHECKING THE FUEL DELIVERY . . . . . . . . . . . . . . . . . . . . . . . . . .350
NTC-6A CHECKING THE COOLANT SENSOR . . . . . . . . . . . . . . . . . . . . . . .352
NTC-7A CHECKING THE THROTTLE POSITION SENSOR . . . . . . . . . . . . .354
NTC-8A CHECKING THE MAP SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . .356
NTC-10A CHECKING THE OXYGEN SENSOR SWITCHING . . . . . . . . . . . . .358
NTC-11A CHECKING THE OXYGEN SENSOR HEATER . . . . . . . . . . . . . . . .364
NTC-12A CHECKING THE IDLE AIR CONTROL MOTOR . . . . . . . . . . . . . . . .366
NTC-13A CHECKING THE ENGINE MECHANICAL . . . . . . . . . . . . . . . . . . . . .368
NTC-15A CHECKING BATTERY TEMP SENSOR . . . . . . . . . . . . . . . . . . . . . .370
NTC-17A CHECKING THE EVAPORATIVE EMISSION SYSTEM . . . . . . . . . .372
NTC-19A CHECKING THE INTAKE AIR TEMPERATURE SENSOR . . . . . . . .378
NTC-20A CHECKING THE PARK/NEUTRAL POSITION SWITCH . . . . . . . . .380
NTC-21A CHECKING THE OIL PRESSURE SENDING UNIT . . . . . . . . . . . . .388
NTC-25A CHECKING THE FUEL LEVEL SENSOR . . . . . . . . . . . . . . . . . . . . .394
NTC-26A CHECKING THE A/C SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . .396
NTC-27A CHECKING THE RADIATOR FAN OPERATION. . . . . . . . . . . . . . . .398
iii
TABLE OF CONTENTS - Continued
SPEED
SC-1A
SC-2A
SC-3A
SC-4A
SC-5A
CONTROL TESTS
CHECKING THE SPEED CONTROL SYSTEM. . . . . . . . . . . . . . . . .402
CHECKING SPEED CONTROL ON/OFF SWITCH. . . . . . . . . . . . . .412
CHECKING THE SPEED CONTROL RESUME SWITCH . . . . . . . .416
CHECKING THE BRAKE SWITCH SENSE. . . . . . . . . . . . . . . . . . . .418
CHECKING THE SPEED CONTROL OPERATION . . . . . . . . . . . . .422
CHARGING TESTS
CH-1A CHARGING SYSTEM NO CODE TEST . . . . . . . . . . . . . . . . . . . . . .424
NO START TESTS
NS-SEL NO START SELECTION MENU . . . . . . . . . . . . . . . . . . . . . . . . . . . . .430
NS-1A QUALIFYING A NO START CONDITION. . . . . . . . . . . . . . . . . . . . . .432
NS-2A CHECKING THE FUEL SYSTEM. . . . . . . . . . . . . . . . . . . . . . . . . . . .442
NS-3A CHECKING ENGINE MECHANICAL SYSTEMS . . . . . . . . . . . . . . . .446
NS-4A REPAIRING LOW FUEL PRESSURE . . . . . . . . . . . . . . . . . . . . . . . .448
NS-5A CHECKING THE FUEL PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .450
NS-6A REPAIRING - NO RESPONSE CONDITION . . . . . . . . . . . . . . . . . . .454
NS-7A CHECKING THE IDLE AIR CONTROL MOTOR . . . . . . . . . . . . . . . .472
NS-8A REPAIRING A START AND STALL CONDITION. . . . . . . . . . . . . . . .478
NS-9A REPAIRING A NO CRANK CONDITION . . . . . . . . . . . . . . . . . . . . . .480
VERIFICATION TEST
VER-1A NO START VERIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .488
VER-2A ROAD TEST VERIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .489
VER-3A CHARGING VERIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .491
VER-4A SPEED CONTROL VERIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . .492
8.0
MAINTENANCE AND SERVICE INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . .493
8.1
8.2
8.3
9.0
SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .494
9.1
10.0
PROGRAMMING THE POWERTRAIN CONTROL MODULE . . . . . . . . . . . . .493
PROGRAMMING THE SENTRY KEY IMMOBILIZER MODULE . . . . . . . . . . .493
PROGRAMMING IGNITION KEYS TO THE SENTRY KEY IMMOBILIZER
MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .493
FUEL SYSTEM RELEASE PROCEDURE (GASOLINE). . . . . . . . . . . . . . . . . .494
SCHEMATIC DIAGRAMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .495
10.1
10.2
10.3
TJ BODY 2.5/4.0L JTEC+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .495
XJ BODY 2.5L JTEC+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .496
XJ BODY 4.0 JTEC+. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .497
11.0
RECOMMENDED TOOLS AND EQUIPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .498
12.0
GLOSSARY OF TERMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .498
iv
1.0
INTRODUCTION
The procedures contained in this manual include all the specifications, instructions, and graphics
needed to diagnose powertrain control module (PCM) problems; they are no start, diagnostic
trouble code, and no trouble code problems for the PCM. The diagnostics in this manual are
based on the failure condition or symptom being present at the time of diagnosis.
When repairs are required, refer to the appropriate volume of the service manual for proper
removal and repair procedure.
Diagnostic procedures change every year. New diagnostic systems may be added; carryover
systems may be enhanced. READ THE GENERAL INFORMATION SECTIONS IN THIS
MANUAL BEFORE TRYING TO DIAGNOSE A VEHICLE TROUBLE CODE. It is recommended
that you review the entire manual to become familiar with all new and changed diagnostic
procedures.
This book reflects many suggested changes from readers of past issues. After using this book, if
you have any comments or recommendations, please fill out the form at the back of the book and
mail it back to us.
1.1
System Coverage
This diagnostic procedures manual covers all 1999 TJ and XJ vehicles equipped with a JTEC
PLUS engine controller.
1.2
Six-Step Troubleshooting Procedure
Diagnosis of the powertrain control module (PCM) is done in six basic steps:
•
•
•
•
•
•
2.0
verification of complaint
verification of any related symptoms
symptom analysis
problem isolation
repair of isolated problem
verification of proper operation
IDENTIFICATION OF SYSTEM
The powertrain control module (PCM) monitors and controls the engine, fuel system, ignition
system, and automatic transmission.
3.0
SYSTEM DESCRIPTION AND FUNCTIONAL OPERATION
3.1
General Description
The Jeep engine and Auto Transmission systems have the latest in technical advances. The
on-board diagnostics incorporated with the PCM controller are intended to assist the field
technician in repairing vehicle problems by the quickest means.
3.2
JTEC + Controller and Operating Modes
3.2.1
Overview
The JTEC + PCM features a multi-processor environment (one 16 bit microcomputer, two 8 bit
microcomputer) allowing parallel processing of time critical operations. Dedication of one 8 bit processor
(K4) to spark control and the other 8 bit processor (D3) to fuel control allows increases in throughput and
reduced software complexity in the 16 bit microcomputer (Z2). The result is increased capability in the Z2
to handle overall strategy implementation, and other computation-intensive processes.
1
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
3.2.2
I
N
F
O
R
M
A
T
I
O
N
The microcomputers communicate over a bus which allows for rapid transmission of high priority
messages. The Z2 executes the primary powertrain control strategy; transmits fuel and spark
requirements to the D3 and K4; communicates with outside devices; and processes 14 analog
inputs and about half of the one bit inputs and outputs. The D3 microcomputer controls fuel
injector timing pulses and a small number of one bit inputs and outputs. The K4 controls spark
timing pulses, processes 8 analog inputs and a number of one bit inputs and outputs.
Hardware Architecture
The design of the PCM can be broken up into about eight major sections. The main
microcontroller, a Motorola MC68HC16Z2, is attached to a 256k byte memory device (flash
memory) which is programmed after manufacture of the module. (This memory can be
reprogrammed at the factory or at a dealership. The MC68HC11D3 and MC68HC11K4 microcomputers have memories which are permanently programmed during their manufacture, and
therefore cannot be reprogrammed.)
Other major sections of the PCM design include the power supply, input conditioning circuits,
output driver circuits, serial communication interface circuits, and a device which controls ignition
coil currents.
3.2.3
Software Architecture
The 68HC16Z2 microcontroller is the main computing unit of the PCM. The 68HC11D3 and K4
microcontrollers control fuel and spark respectively. They handle the critical timing requirements
of their tasks, communicating with the Z2 using high level commands.
The Z2 operating system is the heart of the software and was written expressly for this PCM.
Every 500 microseconds the Z2 interrupts what it is doing to perform periodic tasks such as
updating sensor inputs values and checking for the occurrence of a crank position pulse. If this
pulse is observed, a program known as the decision maker is executed and performs high priority
tasks such as fuel and spark calculations, and RPM processing. Low priority tasks (SCI and CCD
communications) are executed during the time between crank pulses.
The Z2 software is divided into a main oeprating strategy and three separate calibration areas.
The main strategy contains information specific to the various engines and transmissions
supported by this PCM. Once installed, the information contained in this area is fixed for a given
engine and transmission. Changes to this data, if required, can be performed only by computer
programming personnel. The calibration areas (engine and transmission) contain information
relating to emissions, fuel economy and driveability and can be altered directly by calibration
personnel.
3.2.4
Spark Control
The K4 microcomputer controls the generation and timing of spark pulses. The spark advance
and dwell characteristics are determined by: engine speed, throttle position, MAP, coolant
temperature, barometric air pressure, air temperature, and vehicle speed.
3.2.5
Fuel Control
The PCM controls the air/fuel ratio of the enigne by varying fuel injector on time. Mass air flow is
calculated using the speed density method using engine speed, manifold absolute pressure, and
air charge temperature.
Different fuel calculation strategies are used dependent on the operational state of the engine.
During crank mode, a prime shot fuel pulse is delivered followed by fuel pulses determined by a
crank time strategy. Cold engine operation is determined via an open loop strategy until O2
sensors have reached operating temperature. At this point, the strategy enters a closed loop
mode where fuel requirements are based upon the state of the O2 sensors, engine speed, MAP,
throttle position, air temperature, battery voltage, and coolant temperature.
2
Additional factors can influence fuel pulse width. Asynchronous acceleration enrichment is a
technique whereby the duration of injector “on” time can be increased for injectors already firing,
providing improved acceleration response.
The D3 microcomputer controls fuel injector timing in response to high level commands from the
Z2 microcomputer. Injector timing, with respect to engine position, is determined by the D3 and
is transparent to the Z2.
3.2.6
On Board Diagnostics
The PCM has been programmed to monitor many different circuits of the fuel injection system.
This monitoring is called “on-board diagnosis.”
Certain criteria, or “arming conditions,” must be met for a trouble code to be entered into the PCM
memory. The criteria may be a range of: engine rpm, engine temperature, and/or input voltage to
the PCM. If a problem is sensed with a monitored circuit, and all of the criteria or arming conditions
are met, a trouble code will be stored in the PCM.
It is possible that a trouble code for a monitored circuit may not be entered into the PCM memory
even though a malfunction has occurred. This may happen because one of the trouble code
criteria (arming conditions) has not been met.
The PCM compares input signal voltages from each input device with specifications (the
established high and low limits of the range) that are programmed into it for that device. If the input
voltage is not within specifications and other trouble code criteria (arming conditions) are met, a
trouble code will be stored in the PCM memory.
3.2.7
Transmission Control (4.0L - XJ Body Only)
Control of the transmission on this vehicle is done by a separate Transmission Control Module
(TCM). The TCM is also called an AW4 TCM. Diagnostics for this TCM are found in another
diagnostic manual called, the AW4 Powertrain Diagnostic Manual.
3.2.8
Other Controls
Cruise Control
The PCM controls vehicle speed by operation of the speed control servo vacuum and vent
solenoids. Energizing the vacuum solenoid applies vacuum to the servo to increase throttle
position. Operation of the vent solenoid slowly releases the vacuum allowing throttle position to
decrease. A special dump solenoid allows immediate release of throttle position caused by
braking, cruise control turned off, or ignition key off.
Fuel Vapor Recovery System (Duty Cycle Purge Control)
Duty Cycle Purge is a system that feeds fuel gases from the purge canister and gasoline tank into
the throttle body for mixing with incoming air. Metering of the gases is performed by duty cycling
the purge solenoid by the PCM.
The system is disabled during wide open throttle conditions and while the engine is below a
specified coolant temperature. When engine temperature becomes greater than a calibrated
parameter, duty cycle purge is delayed for a calibrated time. Once purge delay is over, purge will
be ramped into soften the effect of dumping additional fuel into the engine.
The PCM provides a modulated 5 hz signal (at closed throttle) or 10 hz signal (at open throttle)
to control this sytem. Modulation of the signal is based upon a calculated air flow (based upon
known fuel flow through the injector at a given pulsewidth and RPM) and is adjusted to
compensate for changes in flow due to varying engine vacuum.
3
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
3.2.9
PCM Operating Modes
As input signals to the PCM change, the PCM adjusts its response to output devices. For
example, the PCM must calculate a different injector pulse width and ignition timing for idle than
it does for wide open throttle. There are several different modes of operation that determine how
the PCM responds to the various input signals.
There are two types of engine control operation: open loop and closed loop.
In open loop operation, the PCM receives input signals and responds according to preset
programming. Inputs from the heated oxygen sensors are not monitored.
In closed loop operation, the PCM monitors the inputs from the heated oxygen sensors. This input
indicates to the PCM whether or not the calculated injector pulse width results in the ideal air-fuel
ratio of 14.7 parts air to 1 part fuel. By monitoring the exhaust oxygen content through the oxygen
sensor, the PCM can fine tune injector pulse width. Fine tuning injector pulse width allows the
PCM to achieve optimum fuel economy combined with low emissions.
The engine start-up (crank), engine warm-up, and wide open throttle modes are open loop
modes. Under most operating conditions, the acceleration, deceleration, and cruise modes, with
the engine at operating temperature, are closed loop modes.
Ignition Switch On (Engine Off) Mode
When the ignition switch activates the fuel injection system, the following actions occur:
1.
The PCM determines atmospheric air pressure from the MAP sensor input to
determine basic fuel strategy.
2.
The PCM monitors the engine coolant temperature sensor and throttle position
sensor input. The PCM modifies fuel strategy based on this input.
When the Ignition key is in the “on” position and the engine is not running (zero rpm), the auto
shutdown relay and fuel pump relay are not energized. Therefore, voltage is not supplied to the
fuel pump, ignition coil, and fuel injectors.
Engine Start-Up Mode —This is an open loop mode. The following actions occur when the
starter motor is engaged:
1.
The auto shutdown and fuel pump relays are energized. If the PCM does not
receive the camshaft and crankshaft signals within approximately one second,
these relays are de-energized.
2.
The PCM energizes all fuel injectors until it determines crankshaft position from
the camshaft and crankshaft signals. The PCM determines crankshaft position
within one engine revolution. After the crankshaft position has been determined,
the PCM energizes the fuel injectors in sequences. The PCM adjusts the injector
pulse width and synchronizes the fuel injectors by controlling the fuel injectors’
ground paths.
Once the auto shutdown and fuel pump relays have been energized, the PCM determines the fuel
injector pulse width based on the following:
–
–
–
–
–
engine coolant temperature
manifold absolute pressure
intake air temperature
engine revolutions
throttle position
The PCM determines the spark advance based on the following:
–
–
–
engine coolant temperature
crankshaft position
camshaft position
4
–
–
–
intake air temperature
manifold absolute pressure
throttle position
Engine Warm-Up Mode — This is an open loop mode. The PCM adjusts injector pulse width and
controls injector synchronization by controlling the fuel injectors’ ground paths. The PCM adjusts
ignition timing and engine idle speed. The PCM adjusts the idle speed by controlling the idle air
control motor.
Cruise or Idle Mode — When the engine is at normal operating temperature, this is a closed
loop mode. During certain idle conditions, the PCM may enter into a variable idle speed strategy.
At this time, the PCM adjusts engine speed based on the following inputs:
–
–
–
throttle position
battery voltage
engine coolant temperature
Acceleration Mode — This is a closed loop mode. The PCM recognizes an increase in throttle
position and a decrease in Manifold Vacuum as engine load increases. In response, the PCM
increases the injector pulse width to meet the increased load.
Deceleration Mode — This is a closed loop mode. The PCM recognizes a decrease in throttle
position and an increase in Manifold Vacuum as engine load decreases. In response, the PCM
decreases the injector pulse width to meet the decreased load.
Wide Open Throttle Mode — This is an open loop mode. The throttle position sensor notifies the
PCM of a wide open throttle condition. The PCM adjusts injector pulse width to supply a
predetermined amount of additional fuel.
3.2.10
Non-Monitored Circuits
The PCM does not monitor the following circuits, systems, and conditions even though they could
have malfunctions that result in driveability problems. A diagnostic code may not be displayed for
the following conditions. However, problems with these systems may cause a diagnostic code to
be displayed for other systems. For example, a fuel pressure problem will not register a diagnostic
code directly, but could cause a rich or lean condition. This could cause an oxygen sensor, fuel
system, or misfire monitor trouble code to be stored in the PCM.
Engine Timing — The PCM cannot detect an incorrectly indexed timing chain, camshaft
sprocket, or crankshaft sprocket. The PCM also cannot detect an incorrectly indexed distributor.
(*)
Fuel Pressure — Fuel pressure is controlled by the fuel pressure regulator. The PCM cannot
detect a clogged fuel pump inlet filter, clogged in-line fuel filter, or a pinched fuel supply. (*)
Fuel Injectors — The PCM cannot detect if the fuel injector is clogged, the pintle is sticking, or
the wrong injectors are installed. (*)
Fuel Requirements — Poor quality gasoline can cause problems such as hard starting, stalling,
and stumble. Use of methanol-gasoline blends may result in starting and driveability problems.
(See individual symptoms and their definitions in Section 12.0 (Glossary of Terms) at the back of
this book.)
PCM Grounds — The PCM cannot detect a poor system ground. However, a diagnostic trouble
code may be stored in the PCM as a result of this condition.
Throttle Body Air Flow — The PCM cannot detect a clogged or restricted air cleaner inlet or filter
element.(*)
Exhaust System — The PCM cannot detect a plugged, restricted, or leaking exhaust system.(*)
Cylinder Compression — The PCM cannot detect uneven, low, or high engine cylinder
compression.(*)
5
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
Excessive Oil Consumption — Although the PCM monitors the exhaust stream oxygen content
through the oxygen sensor when the system is in a closed loop, it cannot determine excessive oil
consumption.
(*)NOTE: Any of these conditions could result in a rich or lean condition causing an oxygen sensor
trouble code to be stored in the PCM, or the vehicle may exhibit one or more of the driveability
symptoms listed in TEST NTC−1A − No Trouble Code Test Menu.
3.2.11
SKIS OVERVIEW
The Sentry Key Immobilizer System (SKIS) is an immobilizer system designed to prevent
unauthorized vehicle operation. The system consists of a Sentry Key Immobilizer Module (SKIM),
ignition key(s) equipped with a transponder chip and powertrain controller. When the ignition
switch is turned on, the SKIM interrogates the ignition key. If the ignition key is “Valid” the SKIM
sends a CCD Bus message to the powertrain controller indicating the presence of a valid ignition
key. With a valid key presence, the PCM allows the engine to continue to operate.
3.2.12
SKIS OPERATION
When ignition power is supplied to the SKIM, the SKIM performs an internal self-test. After the
self-test is completed, the SKIM energizes the antenna (this activates the transponder chip) and
sends a challenge to the transponder chip. The transponder chip responds to the challenge by
generating an encrypted response message using the following:
Secret Key — This is an electronically stored value (identification number) that is unique to each
SKIS. The secret key is stored in the SKIM, PCM and all ignition key transponders.
Challenge —This is a random number that is generated by the SKIM at each ignition key cycle.
The secret key and challenge are plugged into an algorithm that produces the encrypted response
message. The transponder uses the crypto algorithm to receive, decode and respond to the
message sent by SKIM. After responding to the coded message, the transponder sends a
transponder ID message to the SKIM. The SKIM compares the transponder ID to the available
valid key codes in SKIM memory (8 key maximum). After validating the key the SKIM sends a
CCD Bus message called a “Seed Request” to the powertrain controller then waits for a
powertrain controller response. If the powertrain controller does not respond, the SKIM will send
the seed request again. After three failed attempts the SKIM will stop sending the seed request
and store a trouble code. If the powertrain controller sends a seed response, the SKIM sends a
valid/invalid key message to the powertrain controller. This is an encrypted message that is
generated using the following:
VIN — Vehicle Identification Number
Seed —This is a random number that is generated by the PCM at each ignition key cycle.
The VIN and seed are plugged into a rolling code algorithm that encrypts the “valid/invalid key”
message. The powertrain controller uses the rolling code algorithm to receive, decode and
respond to the valid/invalid key message sent by SKIM. After sending the valid/invalid key
message the SKIM waits 3.5 seconds for an EMS status message from the powertrain controller.
If the PCM does not respond with a valid key message to the SKIM, a fault is detected and a
trouble code stored.
The SKIS incorporates a yellow warning lamp located in the instrument cluster. The lamp is
illuminated when the SKIM sends a CCD Bus message to the instrument cluster requesting the
lamp on. The SKIM will request lamp operation for the following:
–
–
bulb check at ignition on
to alert the vehicle operator to a SKIS malfunction
For all faults except transponder faults and VIN mismatch, the lamp remains on steady. In the
event of a transponder fault the light flashes at the rate of 1Hz (once per second). If a fault is
present the lamp will remain on or flashing for the complete ignition cycle.
6
3.3
Diagnostic Trouble Codes
Each diagnostic trouble code is diagnosed by following a specific testing procedure. The
diagnostic test procedures contain step-by-step instructions for determining the cause of trouble
codes as well as no trouble code problems. It is not necessary to perform all of the tests in this
book to diagnose an individual code.
Always begin by reading the diagnostic trouble codes using the DRB. This procedure begins in
the DTC TEST Section 7.1 — Checking the System for Diagnostic Trouble Codes. This will direct
you to the specific test(s) that must be performed.
3.3.1
Hard Code
A diagnostic trouble code that returns within one cycle of the required parameters is a “hard” code.
This means that the defect is there every time the powertrain control module checks that circuit
or function. Procedures in this manual verify if the trouble code is a hard code at the beginning
of each test. When it is not a hard code, an “intermittent” test must be performed.
3.3.2
Intermittent Code
A diagnostic trouble code that is not there every time the powertrain control module checks the
circuit is an “intermittent” code. Most intermittent codes are caused by wiring or connector
problems. Defects that come and go like this are the most difficult to diagnose; they must be
looked for under specific conditions that cause them. The following checks may assist you in
identifying a possible intermittent problem.
•
•
•
Visually inspect related wire harness connectors. Look for broken, bent, pushed out, or
corroded terminals.
Visually inspect the related harnesses. Look for chafed, pierced, or partially broken wire.
Refer to any hotlines or technical service bulletins that may apply.
3.3.3
Reset Counter
The reset counter counts the number or times the vehicle has been started since codes were last
set, erased, or the battery was disconnected. The reset counter will count up to 255 start counts.
The number of starts helps determine when the trouble code actually happened. This is recorded
by the PCM and can be viewed on the DRB as the RESET COUNTER.
When there are no trouble codes stored in memory, the DRB will display “NO TROUBLE CODES
FOUND” and the reset counter will show “RESET COUNT = XXX.”
3.3.4
Handling No Trouble Code Problems
After reading Section 3.0 (System Description and Functional Operation), you should have a
better understanding of the theory and operation of the on-board diagnostics, and how this relates
to the diagnosis of a vehicle that may have a driveability-related symptom or complaint.
The “no code” system is broken down into two test methods:
–
–
3.4
No Code Complete Test
No Code Quick Individual Test
Using the DRBIIIT
Refer to the DRB user’s guide for instructions and assistance with reading trouble codes, erasing
trouble codes, and other DRB functions.
7
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
3.5
DRBIIIT Error Messages and Blank Screen
Under normal operation, the DRB will display one of only two error messages:
–
User-Requested WARM Boot or User-Requested COLD Boot
This is a sample of such an error message display:
ver: 2.14
date: 26 Jul93
file: key_itf.cc
line: 548
err: 0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.5.1
DRBIIIT Does Not Power Up
If the LED’s do not light or no sound is emitted at start up, check for loose cable connections or
a bad cable. Check the vehicle battery voltage (data link connector cavity 16). A minimum of 11
volts is required to adequately power the DRB.
If all connections are proper between the DRB and the vehicle or other devices, and the vehicle
battery is fully charged, an inoperative DRB may be the result of faulty cable or vehicle wiring. For
a blank screen, refer to the appropriate body diagnostics manual.
3.5.2
Display Is Not Visible
Low temperatures will affect the visibility of the display. Adjust the contrast to compensate for this
condition.
8
4.0
SYSTEM COMPONENT LOCATIONS
4.1
Powertrain Control Module
G
E
N
E
R
A
L
TJ BODY
I
N
F
O
R
M
A
T
I
O
N
CAV
CKT/COLOR
FUNCTION
CAV
CKT/COLOR
FUNCTION
A2
A4
A6
A7
A8
A10
A11
A12
F12 DB
K167 BR/YL
T41 BR/LB
K19 GY
K24 GY/BK
K60 YL/BK
K40 BR/WT
K10 DB/BR
B11
T23 OR/LG
A15
A16
A17
A18
K21 BK/RD
K2 TN/BK
K7 OR
K44 TN/YL
B12
B15
B16
B23
B27
B31
C1
C3
C4
K16 LG/BK
K12 TN
K14 LB/BR
G60 GY/YL
G7 WT/OR
K6 VT/OR
C13 DB/OR
K51 DB/YL
V36 TN/RD
A19
A20
A22
A23
A24
A25
K39 GY/RD
K59 VT/ BK
A14 RD/WT
K22 OR/DB
K41 BK/DG
K141 TN/WT
A27
A31
A32
B4
B5
B6
B10
K1 DG/RD
Z12 BK/TN
Z12 BK/TN
K11 WT/DB
K13 YL/WT
K15 PK/BK
K20 DG
Fused Ignition Switch Output
Sensor Ground
P/N Position Switch Sense
Ignition Coil Driver
Crank Position Sensor Signal
Idle Air Control #3 Driver
Idle Air Control #2 Driver
Power Steering Pressure Switch
Sense (2.5L)
Intake Air Temp Sensor Signal
ECT Sensor Signal
5-Volt Supply (Primary)
Camshaft Position Sensor
Signal
Idle Air Control #4 Driver
Idle Air Control #1 Driver
Fused B(+)
Throttle Position Sensor Signal
Upstream O2 Sensor Signal 1/1
Downstream O2 Sensor
Signal 1/2
MAP Sensor Signal
Ground
Ground
Injector #1 Driver
Injector #3 Driver
Injector #5 Driver
Generator Field Driver (-)
C5
C11
C12
C15
C19
C20
C22
C23
C24
C25
C26
C27
C28
C29
C30
C32
V35 LG/RD
V32 YL/RD
A142 DG/PK
K118 PK/YL
K31 BR
K52 PK/BK
C22 DB/WT
C90 LG
K29 WT/PK
K72 DG/OR
K226 DB/LG
D21 PK
D2 WT/BK
D20 LG
D1 VT/BR
V37 RD/LG
TCC Solenoid Control (ATX
ONLY)
Injector #6 Driver
Injector #2 Driver
Injector #4 Driver
Oil Pressure Sensor Signal
Vehicle Speed Sensor Signal
5-Volt Supply (Secondary)
A/C Comp Clutch Relay Control
Auto Shutdown Relay Control
Speed Control Vacuum Sol
Control
Speed Control Vent Sol Control
S/C 12-Volt Supply
Auto Shutdown Relay Output
Battery Temp Sensor Signal
Fuel Pump Relay Control
Evap Emission Solenoid Control
A/C Switch Sense
A/C Switch Output
Brake Switch Sense
Generator Field Source (+)
Fuel Level Sensor Signal
SCI Transmit
CCD Bus (-)
SCI Receive
CCD Bus (+)
S/C Switch Signal
9
G
E
N
E
R
A
L
4.1
Powertrain Control Module (Continued)
XJ BODY
I
N
F
O
R
M
A
T
I
O
N
CAV
CKT/COLOR
FUNCTION
CAV
CKT/COLOR
FUNCTION
A2
A4
A6
A6
A6
F12 DB/WT
K167 BR/YL
T41 BR/LB
Z1 BK
T41 BK/WT
A7
A8
A10
A11
A12
K19
K24
K60
K40
K10
A15
A16
A17
A18
A19
A20
A22
A23
A24
A25
A27
A31
A32
B4
B5
B6
K21 BK/RD
K2 TN/BK
K7 OR
K44 TN/YL
K39 GY/RD
K59 VT/BK
A61 DG/BK
K22 OR/DB
K41 BK/DG
K141 TN/WT
K1 DG/RD
Z12 BK/TN
Z12 BK/TN
K11 WT/DB
K13 YL/WT
K15 PK/BK
Fused Ignition Switch Output
Sensor Ground
PNP Switch Sense (2.5L A/T)
Ground (2.5L M/T)
Transmission Range Switch
Sense (4.0L A/T)
Ign Coil Driver
CKP Sensor Signal
Idle Air Control #3 Driver
Idle Air Control #2 Driver
Power Steering Pressure Switch
(2.5L)
IAT Signal
ECT Sensor Signal
5-Volt Supply (Primary)
CMP Sensor Signal
Idle Air Control #4 Driver
Idle Air Control #1 Driver
Fused B(+)
TP Sensor Signal
O2 Sensor 1/1 Signal
O2 Sensor 1/2 Signal
MAP Sensor Signal
Ground
Ground
Injector #1 Driver
Injector #3 Driver
Injector #5 Driver
B10
B11
B12
B15
B16
B23
B27
B31
C1
C2
C3
C4
C5
C11
C12
C15
C19
C20
C22
C23
C24
C25
C26
C27
C28
C29
C30
C32
K20 DG
K54 OR/BK
K16 LG/BK
K12 TN
K14 LB/BR
G60 GY/YL
G7 WT/OR
K6 VT/OR
C13 DB/OR
C27 DB/PK
K51 DB/YL
V36 TN/RD
V35 LG/RD
V32 YL/RD
A142 DG/OR
K118 PK/YL
K31 BR
K52 PK/BK
C22 DB/WT
C90 LG
K29 WT/PK
K72 DG/OR
K226 DB/LG
D21 PK
D2 WT/BK
D20 LG/BK
D1 VT/BR
V37 RD/LG
Generator Field Driver (-)
TCC Solenoid Control (2.5L A/T)
Injector #6 Driver
Injector #2 Driver
Injector #4 Driver
Oil Press Sensor Signal
Vehicle Speed Sensor Signal
5-Volt Supply (Secondary)
A/C Comp Clutch Relay Control
Rad Fan Relay Control
ASD Relay Control
S/C Vacuum Solenoid Control
S/C Vent Solenoid Control
S/C 12-Volt Supply
ASD Relay Output
Batt Temp Sensor Signal
Fuel Pump Rly Ctrl
EVAP Sol Control
A/C Pressure Switch Output
A/C Select Input
Brake Switch Sense
Generator Field Source (+)
Fuel Level Sensor
SCI Transmit
CCD Bus (-)
SCI Receive
CCD Bus (+)
S/C SW Signal
GY
GY/BK
YL/BK
BR/WT
DB/BR
10
4.2
Controls & Solenoids
TJ BODY
XJ BODY
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
TJ/XJ BODY
TJ/XJ 2.5L
TJ/XJ 4.0L
TJ/XJ BODY
11
G
E
N
E
R
A
L
4.2
Controls & Solenoids (Continued)
TJ/XJ 2.5L BODY
TJ/XJ 4.0L
TJ/XJ 2.5L
TJ/XJ 4.0L
TJ/XJ 2.5L
TJ/XJ 4.0L
I
N
F
O
R
M
A
T
I
O
N
12
TJ BODY
XJ BODY
TJ BODY
XJ BODY
TJ/XJ BODY
13
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
4.3
Data Link Connector
TJ BODY
TJ BODY
XJ BODY
XJ BODY
I
N
F
O
R
M
A
T
I
O
N
4.4
Sensors
TJ/XJ BODY
TJ/XJ BODY
14
TJ/XJ BODY
TJ/XJ BODY
TJ/XJ 2.5L & 4.0L
TJ/XJ BODY
TJ/XJ 2.5L & 4.0L
TJ BODY
15
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
4.4
Sensors (Continued)
XJ BODY
TJ/XJ 2.5L
TJ/XJ 4.0L
TJ BODY
XJ BODY
TJ/XJ BODY
I
N
F
O
R
M
A
T
I
O
N
16
TJ 2.5L & 4.0L 1/1
XJ 2.5L & 4.0L 1/1
TJ 2.5L & 4.0L 1/2
TJ BODY 1/1
TJ BODY 1/2
17
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
4.4
Sensors (Continued)
XJ BODY 1/1
XJ BODY 1/2
TJ/XJ 2.5L
TJ/XJ 4.0L
TJ/XJ BODY
TJ/XJ BODY
I
N
F
O
R
M
A
T
I
O
N
18
4.5
Fuel System
TJ BODY
XJ BODY
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
TJ BODY
4.6
XJ BODY
Relays
TJ BODY
XJ BODY
19
G
E
N
E
R
A
L
4.6
Relays (Continued)
TJ BODY
XJ BODY
TJ BODY
XJ BODY
TJ BODY
XJ BODY
I
N
F
O
R
M
A
T
I
O
N
20
G
E
N
E
R
A
L
XJ BODY
4.7
I
N
F
O
R
M
A
T
I
O
N
Switches
TJ/XJ BODY
TJ BODY
XJ BODY
TJ/XJ BODY
21
G
E
N
E
R
A
L
4.7
Switches (Continued)
TJ/XJ
I
N
F
O
R
M
A
T
I
O
N
XJ BODY 4.0L
TJ/XJ 2.5L
TJ/XJ 2.5L
22
5.0
DISCLAIMERS, SAFETY, WARNINGS
5.1
Disclaimers
All information, illustrations, and specifications contained in this manual are based on the latest
information available at the time of publication. The right is reserved to make changes at any time
without notice.
5.2
Safety and Warnings
5.2.1
Technician Safety Information
WARNING: Engines produce carbon monoxide that is odorless, causes slower reaction
time, and can lead to serious injury. When the engine is operating, keep service areas
WELL VENTILATED or attach the vehicle exhaust system to the shop exhaust removal
system.
WARNING: Before performing any secondary ignition testing with open sparks, insure
there are no fuel leaks or vapors present in the immediate area.
Set the parking brake and block the wheels before testing or repairing the vehicle. It is especially
important to block the wheels on front-wheel drive vehicles; the parking brake does not hold the
drive wheels.
When servicing a vehicle, always wear eye protection, and remove any metal jewelry such as
watchbands or bracelets that might make an inadvertent electrical contact.
When diagnosing a body system problem, it is important to follow approved procedures where
applicable. These procedures can be found in General Information Section 9.0 (Specifications) or
in service manual procedures. Following these procedures is very important to the safety of
individuals performing diagnostic tests.
5.2.2
Vehicle Preparation for Testing
Make sure the vehicle being tested has a fully charged battery. If it does not, false diagnostic
codes or error messages may occur.
5.2.3
Servicing Sub-Assemblies
Some components of the powertrain system are intended to be serviced in assembly only.
Attempting to remove or repair certain system sub-components may result in personal injury
and/or improper system operation. Only those components with approved repair and installation
procedures in the service manual should be serviced.
5.2.4
DRBIIIT Safety Information
WARNING: Exceeding the limits of the DRBIIIT multimeter is dangerous. It can expose you
to serious or possibly fatal injury. Carefully read and understand the cautions and the
specification limits.
•
Follow the vehicle manufacturer’s service specifications at all times.
•
Do not use the DRB if it has been damaged.
•
Do not use the test leads if the insulation is damaged or if metal is exposed.
•
To avoid electrical shock, do not touch the test leads, tips, or the circuit being tested.
•
Choose the proper range and function for the measurement. Do not try voltage or current
measurements that may exceed the rated capacity.
23
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
•
Do not exceed the limits shown in the table below:
FUNCTION
INPUT LIMIT
Volts
0 - 500 peak volts AC
0 - 500 volts DC
Ohms (resistance)*
0 - 1.12 megohms
Frequency Measured
Frequency Generated
0 - 10 kHz
Temperature
-58 - 1100° F
-50 - 600° C
* Ohms cannot be measured if voltage is
present. Ohms can be measured only in a
non-powered circuit.
•
Voltage between any terminal and ground must not exceed 500v DC or 500v peak AC.
•
Use caution when measuring voltage above 25v DC or 25v AC.
•
The circuit being tested must be protected by a 10A fuse or circuit breaker.
•
Use the low current shunt to measure circuits up to 10A. Use the high current clamp to
measure circuits exceeding 10A.
•
When testing for the presence of voltage or current, make sure the meter is functioning
correctly. Take a reading of a known voltage or current before accepting a zero reading.
•
When measuring current, connect the meter in series with the load.
•
Disconnect the live test lead before disconnecting the common test lead.
•
When using the meter function, keep the DRB away from spark plug or coil wires to avoid
measuring error from outside interference.
5.3
Warnings and Cautions
5.3.1
Vehicle Damage Warnings
Before disconnecting any control module, make sure the ignition is ‘‘off’’. Failure to do so could
damage the module.
When testing voltage or continuity at the powertrain control module, use the terminal side (not the
wire end) of the connector. Do not probe a wire through the insulation; this will damage it and
eventually cause it to fail because of corrosion.
Be careful when performing electrical tests so as to prevent accidental shorting of terminals. Such
mistakes can damage fuses or components. Also, a second code could be set, making diagnosis
of the original problem more difficult.
5.3.2
Road Testing a Complaint Vehicle
Some complaints will require a test drive as part of the repair verification procedure. The purpose
of the test drive is to try to duplicate the diagnostic code or symptom condition.
CAUTION: Before road testing a vehicle, be sure that all components are reassembled.
During the test drive, do not try to read the DRBIIIT screen while in motion. Do not hang the
DRB from the rear view mirror or operate it yourself. Have an assistant available to operate
the DRBIIIT.
24
7.0
DIAGNOSTIC INFORMATION AND PROCEDURES
7.1
GENERAL
TROUBLESHOOTING
25
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
DTC TEST
CHECKING THE SYSTEM FOR DIAGNOSTIC TROUBLE CODES
NOTE: For all component locations, REFER TO GENERAL INFORMATION sections 4.0 in this
manual.
NOTE: The battery must be fully charged for any test in this manual.
1. Attempt to start the engine. Crank for up to 10 seconds if necessary.
2. Connect the DRB to the engine diagnostic connector. Write down the trouble codes that are
displayed.
3. If the DRB screen displays ‘‘No Response’’, go to the TEST NS-SEL.
4. If the DRB screen is blank or has a DRB message, go to General Information Section 3.5 in
this manual.
5. If trouble code messages are displayed, refer to the trouble code list below and on the next
page for the appropriate test.
6. If there are no trouble codes displayed, refer to one of the following:
For
For
For
For
For
SKIS problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SK-1A
Driveability problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-1A
No Start problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-SEL
Speed Control problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .SC-1A
Charging problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .CH-1A
NOTE: The decimal test numbers for these trouble codes were derived from the hexadecimal codes
as set in the PCM. Therefore, some test numbers will be missing because all codes are not
applicable to the vehicles covered in this manual.
TROUBLE CODE
TEST #
DESCRIPTION
DTC
HEX
A/C CLUTCH RELAY CIRCUIT
AISIN AW4 TRANS (TCM) DTC PRESENT
AUTO SHUTDOWN RELAY CONTROL CIRCUIT
BATTERY TEMP SENSOR VOLTAGE TOO HIGH
BATTERY TEMP SENSOR VOLTAGE TOO LOW
CHARGING SYSTEM VOLTAGE TOO HIGH
CHARGING SYSTEM VOLTAGE TOO LOW
1/2 02S VOLTS SHORTED TO GND
1/2 02S SHORTED TO VOLTAGE
ECT SENSOR VOLTAGE TOO HIGH
ECT SENSOR VOLTAGE TOO LOW
ENGINE IS COLD TOO LONG
EVAP PURGE SOLENOID CIRCUIT
FUEL LEVEL SENDING UNIT NO CHANGE OVER TIME
FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
FUEL LEVEL SENDING UNIT VOLTS TOO LOW
FUEL PUMP RELAY CONTROL CIRCUIT
FUEL SYSTEM LEAN 1/1 LEAN
FUEL SYSTEM RICH 1/1 RICH
GENERATOR FIELD NOT SWITCHING PROPERLY
IDLE AIR CONTROL MOTOR CIRCUIT
IGNITION COIL #1 PRIMARY CIRCUIT
INJECTOR #1 CONTROL CIRCUIT
INJECTOR #2 CONTROL CIRCUIT
INJECTOR #3 CONTROL CIRCUIT
INJECTOR #4 CONTROL CIRCUIT
INJECTOR #5 CONTROL CIRCUIT
INJECTOR #6 CONTROL CIRCUIT
TC-16
**
TC-10
TC-153
TC-153
TC-6
TC-5
TC-156
TC-126
TC-31
TC-30
**
TC-18
TC-151
TC-150
TC-149
TC-101
TC-119
TC-118
TC-11
TC-25
TC-43
TC-21
TC-21
TC-21
TC-21
TC-21
TC-21
26
10
89
0A
9A
99
06
05
9C
7E
1F
1E
21
12
F4
96
95
65
77
76
0B
19
2B
15
14
13
3D
45
46
SCAN
TOOL
N/A
P 0700
N/A
P 1492
P 1493
N/A
N/A
P 0137
P 0138
P 0118
P 0117
P 1281
P 0443
P 0461
N/A
N/A
N/A
P 0171
P 0172
N/A
P 0505
P 0351
P 0201
P 0202
P 0203
P 0204
P 0205
P 0206
DTC TEST
CONTINUED - CHECKING THE SYSTEM FOR DIAGNOSTIC TROUBLE CODES
TROUBLE CODE
TEST #
DESCRIPTION
DTC
SCAN
TOOL
HEX
INTAKE AIR TEMP SENSOR VOLTAGE HIGH
INTAKE AIR TEMP SENSOR VOLTAGE LOW
INTERMITTENT LOSS OF CMP OR CKP
INTERNAL CONTROLLER FAILURE
*MAP SENSOR VOLTAGE TOO HIGH
*MAP SENSOR VOLTAGE TOO LOW
NO 5 VOLTS TO MAP SENSOR
NO ASD RELAY OUTPUT VOLTAGE AT PCM
NO CAM SIGNAL AT PCM
NO CCD BUS MESSAGE RECEIVED FROM TCM
NO CCD BUS MESSAGE RECEIVED FROM MIC
NO CCD BUS MESSAGE RECEIVED FROM SKIM
NO CHANGE IN MAP FROM START TO RUN
NO CRANK REFERENCE SIGNAL AT PCM
NO VEHICLE SPEED SENSOR SIGNAL
OIL PRESSURE SENSOR LOW EXCEEDED
OIL PRESSURE SENSOR HIGH EXCEEDED
P/N SWITCH STUCK IN PARK OR IN GEAR
PCM FAILURE EEPROM WRITE DENIED
PCM FAILURE SPI COMMUNICATIONS
POWER STEERING SWITCH FAILURE
RADIATOR FAN CONTROL RELAY CIRCUIT
SPEED CONTROL POWER RELAY OR S/C 12V DRIVER CKT
SPEED CONTROL SOLENOIDS CIRCUITS
SPEED CONTROL SWITCH ALWAYS HIGH
SPEED CONTROL SWITCH ALWAYS LOW
*THROTTLE POSITION SENSOR VOLTAGE HIGH
*THROTTLE POSITION SENSOR VOLTAGE LOW
TORQ CONV CLU, NO RPM DROP AT LOCKUP
TORQUE CONVERTER CLUTCH SOLENOID/TRANS RELAY CKT
*TPS VOLTAGE DOES NOT AGREE WITH MAP
1/1 O2S VOLTAGE SHORTED TO GROUND
1/1 O2 SENSOR SHORTED TO VOLTAGE
WRONG OR INVALID KEY MSG RECEIVED FROM SKIM
TC-58
TC-57
TC-157
**
TC-37
TC-36
TC-36
TC-44
TC-1
**
TC-225
TC-226
TC-39
TC-40
TC-35
TC-235
TC-236
TC-114
TC-49
**
TC-115
TC-14
TC-82
TC-15
TC-86
TC-87
TC-27
TC-26
TC-148
TC-12
TC-132
TC-155
TC-62
TC-232
3A
39
9D
02
25
24
87
2C
01
60
E1
E2
27
28
23
EB
EC
72
31
44
73
OE
52
OF
56
57
1B
1A
94
0C
84
9B
3E
E8
P 0113
P 0112
P 1391
P 0601
P 0108
P 0107
P 1296
P 1389
P 0340
P 1698
P 1687
P 1686
P 1297
P 0320
P 0500
P 0522
P 0523
P 1899
P 1696
P 0600
P 0551
P 1491
N/A
N/A
P 1596
N/A
P 0123
P 0122
P 0740
P 0743
P 0121
P 0131
P 0132
P 1685
* = These DTC’s can be set by Low Fuel Level, add fuel to 1/4 tank and test for DTC to set again.
** = Trouble code information on last page of DTC test.
For an AISIN TRANS (TCM) DTC PRESENT trouble code, use the appropriate Transmission
diagnostic manual, with the DRB read transmission DTC’s.
For an ENGINE IS COLD TOO LONG trouble code, the engine does not warm to 176°F while driving
for at least 20 minutes after a start. See the service manual for cooling system repair (Thermostat).
For an INTERNAL CONTROLLER FAILURE, replace the Powertrain control module and perform
Verification TEST VER-2A.
For a NO CCD/PCI BUS MESSAGE FROM TCM trouble code, use the appropriate trans diagnostic
manual for testing and repair.
For a PCM FAILURE SPI COMMUNICATIONS trouble code, replace the Powertrain control module
and perform Verification TEST VER-2A.
27
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-1A
REPAIRING - NO CAM SIGNAL AT PCM
Perform TEST DTC Before Proceeding
C
O
D
E
T
E
S
T
S
TJ/XJ BODY
FIG. 1
28
TEST TC-1A
T
R
O
U
B
L
E
REPAIRING - NO CAM SIGNAL AT PCM
Perform TEST DTC Before Proceeding
START TEST
TC-1A.
KEY ON. USING THE
DRB, ERASE TROUBLE
CODES.
C
O
D
E
ATTEMPT TO START
THE ENGINE. IF IT
DOES NOT START,
CRANK FOR AT LEAST
15 SECONDS.
USING THE DRB,
READ ALL TROUBLE
CODES.
DID THE CODE "NO
CAM SIGNAL AT PCM"
RETURN?
NO
PERFORM TEST
TC-1C.
YES
REPAIR AS
NECESSARY.*
YES
KEY OFF,
DISCONNECT THE
CAMSHAFT POSITION
SENSOR
CONNECTOR.**
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT OR
MISWIRED?
NO
USING AN OHMMETER,
MEASURE THE CMP
SENSOR GROUND
CIRCUIT...
BETWEEN THE CMP
SENSOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE CMP
SENSOR GROUND
CIRCUIT TO THE
HARNESS SPLICE FOR
AN OPEN.*
YES
KEY ON. USING A
VOLTMETER, MEASURE
THE 5-VOLT SUPPLY
CIRCUIT...
AT THE CAM SENSOR
HARNESS CONNECTOR.
IS THE VOLTAGE
ABOVE 4.0 VOLTS?
NO
FIG. 1
REPAIR THE 5-VOLT
SUPPLY CIRCUIT FOR
AN OPEN.*
YES
CONNECT ONE END OF
A JUMPER WIRE TO
THE CMP SENSOR
SIGNAL CIRCUIT.
FIG. 1
USING THE DRB,
MONITOR CMP COUNT
WHILE TAPPING THE
END OF THE JUMPER
TO SENSOR GROUND.
DOES THE CURRENT
CMP COUNT CHANGE?
YES
PERFORM TEST
TC-1B.
NO
CONTINUE TEST
TC-1A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
29
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-1A
CONTINUED - REPAIRING - NO CAM SIGNAL AT PCM
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
30
TEST TC-1A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - NO CAM SIGNAL AT PCM
TEST TC-1A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
C
O
D
E
T
E
S
T
S
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
CMP SENSOR SIGNAL
CIRCUIT...
BETWEEN THE CMP
SENSOR CONNECTOR
AND THE PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE CMP
SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
FIG. 1
YES
MEASURE THE
RESISTANCE OF THE
CMP SENSOR SIGNAL
CIRCUIT...
BETWEEN THE CMP
SENSOR CONNECTOR AND
THE SENSOR GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
FIG. 1
REPAIR THE CMP
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO THE
SENSOR GROUND.*
NO
MEASURE THE
RESISTANCE OF THE
CMP SENSOR SIGNAL
CIRCUIT...
BETWEEN THE CMP
SENSOR CONNECTOR
AND GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE CMP
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
FIG. 1
NO
MEASURE THE
RESISTANCE BETWEEN
THE CMP SENSOR
SIGNAL CIRCUIT AND
THE...
5-VOLT SUPPLY
CIRCUIT AT THE CMP
SENSOR CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
FIG. 1
YES
REPAIR THE CMP
SENSOR SIGNAL
CIRCUIT FOR A SHORT
TO THE 5-VOLT SUPPLY
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
31
T
R
O
U
B
L
E
TEST TC-1B
REPAIRING - NO CAM SIGNAL AT PCM
C
O
D
E
T
E
S
T
S
FIG. 1
32
TEST TC-1B
T
R
O
U
B
L
E
REPAIRING - NO CAM SIGNAL AT PCM
START TEST
TC-1B.
KEY OFF.
C
O
D
E
REMOVE DISTRIBUTOR
CAP AND ROTOR.
INSPECT THE PULSE
RING FOR DAMAGE OR
MISALIGNMENT.
IS THE PULSE RING
OKAY?
NO
REPAIR OR REPLACE
THE DISTRIBUTOR AND
OR THE PULSE RING AS
NECESSARY.*
FIG. 1
YES
REPLACE THE
CAMSHAFT POSITION
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
33
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-1C
REPAIRING - NO CAM SIGNAL AT PCM
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
34
TEST TC-1C
REPAIRING - NO CAM SIGNAL AT PCM
START TEST
TC-1C.
ATTEMPT TO START
THE ENGINE IF NOT
ALREADY RUNNING.
DOES THE ENGINE
START?
NO
PERFORM NO
START TEST
NS-SEL.
C
O
D
E
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GEN INFO
3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
35
T
R
O
U
B
L
E
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-5A
REPAIRING - CHARGING SYSTEM VOLTAGE TOO LOW
Perform TEST DTC Before Proceeding
C
O
D
E
T
E
S
T
S
TJ/XJ BODY
TJ/XJ BODY
FIG. 1
36
TEST TC-5A
T
R
O
U
B
L
E
REPAIRING - CHARGING SYSTEM VOLTAGE TOO LOW
Perform TEST DTC Before Proceeding
START TEST
TC-5A.
NOTE: BATTERY MUST
BE FULLY CHARGED.
C
O
D
E
NOTE: GENERATOR
BELT TENSION AND
CONDITION MUST BE
CHECKED BEFORE
CONTINUING.
START THE ENGINE.
USING THE DRB,
READ THE TARGET
CHARGING VOLTAGE.
IS THE TARGET
CHARGING VOLTAGE
ABOVE 15.1 VOLTS?
NO
CONTINUE TEST
TC-5A ON THE
NEXT PAGE.
YES
CONTINUE TEST
TC-5A ON THE
NEXT PAGE.
NO
REPLACE POWERTRAIN
CONTROL MODULE.*
YES
USING THE DRB,
READ THE BATTERY
TEMP SENSOR
TEMPERATURE.
USING A
THERMOMETER,
MEASURE UNDER HOOD
TEMPERATURE NEAR
THE BATTERY.
IS THE TEMPERATURE
0
WITHIN -12 C
0
(10 F) OF BATTERY
TEMPERATURE?
NO
DISCONNECT THE
BATTERY
TEMPERATURE SENSOR
CONNECTOR.**
CONNECT A JUMPER
ACROSS TERMINALS OF
THE BATTERY
TEMPERATURE SENSOR.
FIG. 1
USING THE DRB,
READ BATTERY
TEMPERATURE SENSOR
VOLTAGE.
IS THE VOLTAGE
READING EQUAL TO
ZERO?
YES
REPLACE THE
BATTERY
TEMPERATURE
SENSOR.*
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
37
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-5A
CONTINUED - REPAIRING - CHARGING VOLTAGE TOO LOW
C
O
D
E
T
E
S
T
S
FIG. 1
38
TEST TC-5A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - CHARGING VOLTAGE TOO LOW
TEST TC-5A
CONTINUED FROM
THE PREVIOUS
PAGE.
USE A VOLTMETER IN
THE FOLLOWING
STEP.
C
O
D
E
MEASURE BETWEEN THE
GENERATOR (12V) B+
TERMINAL AND THE
BATTERY (+) SIDE.
FIG. 1
CAUTION: ENSURE
ALL WIRES ARE
CLEAR OF THE
ENGINE’S MOVING
PARTS.
T
E
S
T
S
IS THE VOLTAGE
ABOVE 0.4 VOLT?
START THE ENGINE.
YES
REPAIR THE B (+)
CIRCUIT FOR HIGH
RESISTANCE BETWEEN
THE GENERATOR AND
THE BATTERY.*
NO
IGNITION KEY OFF.
USE A VOLTMETER IN
THE FOLLOWING
STEP.
MEASURE BETWEEN THE
GENERATOR CASE AND
BATTERY (-) SIDE.
FIG. 1
CAUTION: ENSURE
ALL WIRES ARE
CLEAR OF THE
ENGINE’S MOVING
PARTS.
IS THE VOLTAGE
ABOVE 0.1 VOLT?
START THE ENGINE.
YES
REPAIR GENERATOR
GROUND FOR HIGH
RESISTANCE
GENERATOR CASE TO
BATTERY (-) SIDE.*
NO
MANUALLY SET ENGINE
SPEED TO 1600 RPM.
WITH DRB, READ
TARGET CHARGING AND
VOLTAGE SENSE.
COMPARE THE TWO
READINGS.
IS THERE MORE THAN
A 1.0 VOLT
DIFFERENCE?
YES
CONTINUE TEST
TC-5B ON THE
NEXT PAGE.
NO
ALLOW THE ENGINE
TO RETURN TO IDLE
SPEED.
TURN ENGINE OFF.
(IGNITION KEY ON.)
*Perform Verification TEST VER-3A.
ERASE TROUBLE
CODES.
PERFORM TEST
CH-1A.
**Check connectors - Clean / repair as necessary.
39
T
R
O
U
B
L
E
TEST TC-5B
REPAIRING - CHARGING SYSTEM VOLTAGE TOO LOW
Perform TEST TC-5A Before Proceeding
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
40
TEST TC-5B
T
R
O
U
B
L
E
REPAIRING - CHARGING SYSTEM VOLTAGE TOO LOW
Perform TEST TC-5A Before Proceeding
START TEST
TC-5B.
DISCONNECT THE
GENERATOR FIELD
DRIVER HARNESS
CONNECTOR.**
C
O
D
E
KEY ON. USING A
DRB, ACTUATE THE
GENERATOR FIELD.
USING A TEST LIGHT
CONNECTED TO GROUND,
PROBE GENERATOR
SOURCE (+) CIRCUIT.
FIG. 2
DOES THE TEST
LIGHT ILLUMINATE.
NO
REPAIR THE OPEN IN
THE ASD RELAY
OUTPUT CIRCUIT.*
YES
REPAIR OR REPLACE
THE GENERATOR AS
NECESSARY.*
YES
NOTE: THE
GENERATOR FIELD
STILL ACTUATING.
USING A TEST LIGHT
CONNECTED TO
GENERATOR SOURCE (+)
CKT, PROBE GEN FIELD
DRV CKT. FIG. 2
DOES THE TEST
LIGHT FLASH ON AND
OFF?
NO
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USING A OHMMETER,
MEASURE RESISTANCE
OF THE GENERATOR
FIELD DRIVER CKT.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE GENERATOR
FIELD DRIVER
CIRCUIT.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
41
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-6A
REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
Perform TEST DTC Before Proceeding
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
42
TEST TC-6A
T
R
O
U
B
L
E
REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-6A
DISCONNECT THE
GENERATOR FIELD
DRIVER HARNESS
CONNECTOR.**
WITH THE DRB,
ACTUATE THE
GENERATOR FIELD
DRIVER.
C
O
D
E
USING A TEST LIGHT
CONNECTED TO
BATTERY (+)...
PROBE THE
GENERATOR FIELD
DRIVER CIRCUIT.
FIG. 1
DOES THE TEST
LIGHT FLASH ON AND
OFF?
YES
PERFORM TEST
TC-6B.
NO
WITH THE DRB, STOP
THE GENERATOR
FIELD DRIVER
ACTUATION.
TURN IGNITION OFF.
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
*Perform Verification TEST VER-3A.
CONTINUE TEST
TC-6A ON THE
NEXT PAGE.
**Check connectors - Clean / repair as necessary.
43
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-6A
CONTINUED - REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
FIG. 2
XJ BODY
FIG. 3
44
TEST TC-6A
CONTINUED - REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
TEST TC-6A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING AN OHMMETER,
MEASURE GEN FIELD
DRIVER CKT FROM PCM
HARNESS CONN TO GND.
FIG. 2 OR 3
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
GENERATOR FIELD
DRIVER CIRCUIT
SHORTED TO
GROUND.*
NO
MEASURE THE
RESISTANCE BETWEEN
THE FIELD DRIVER
OR GEN SOURCE (+)
TERMINALS...
AND THE GENERATOR
CASE.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR OR REPLACE
THE SHORTED
GENERATOR AS
NECESSARY.*
FIG. 1
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
45
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-6B
REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
Perform TEST TC-6A Before Proceeding
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
46
TEST TC-6B
REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
Perform TEST TC-6A Before Proceeding
START TEST
TC-6B.
WITH THE DRB, STOP
THE GENERATOR FIELD
DRIVER ACTUATION.
READ THE TARGET
CHARGING VOLTAGE.
IS THE TARGET
CHARGING VOLTAGE
ABOVE 13.0 VOLTS?
YES
CONTINUE TEST
TC-6B ON THE
NEXT PAGE.
C
O
D
E
NO
USING THE DRB TEMP
PROBE, MEASURE
TEMP NEAR
AMBIENT/BATT TEMP
SENSOR.
WITH THE DRB, READ
THE BATTERY TEMP
SENSOR
TEMPERATURE.
IS THE BATTERY
TEMPERATURE
WITHIN
O
o
-12 C (10 F) OF
THE UNDER HODD
TEMPERATURE?
YES
CONTINUE TEST
TC-6B ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.
NO
DISCONNECT THE
AMBIENT/BATTERY TEMP
SENSOR HARNESS CONN
AND INSPECT THE
TERMINALS.
ARE ANY TERMINALS
FOUND TO BE
CORRODED, DAMAGE,
PUSH OUT, OR
MISWIRED?
NO
IS THIS A XJ
VEHICLE?
NO
REPAIR THE BATTERY
TEMPERATURE
SENSOR.*
YES
ARE THERE ANY
AMBIENT/BATTERY
TEMP SENSOR
TROUBLE CODES?
USING THE DRB
UNDER BODY, READ
TROUBLE CODES.
YES
REFER TO BODY
DIAGNOSTIC
PROCEDURE
MANUAL.
NO
REPLACE THE
AMBIENT/BATTERY
TEMPERTURE
SENSOR.*
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
47
T
R
O
U
B
L
E
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-6B
CONTINUED - REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
NOTES
C
O
D
E
T
E
S
T
S
48
TEST TC-6B
CONTINUED - REPAIRING - CHARGING SYSTEM VOLTAGE TOO HIGH
TEST TC-6B
CONTINUED FROM
THE PREVIOUS
PAGE.
START THE ENGINE.
T
R
O
U
B
L
E
C
O
D
E
MANUALLY SET THE
ENGINE SPEED TO
1600 RPM.
COMPARE THE
"TARGET" TO THE
"VOLT" READING.
WITH THE DRB, READ
BOTH THE VOLTAGE
SENSE AND THE
TARGET CHARGING
VOLTAGE.
T
E
S
T
S
WATCH FOR UP TO 5
MINUTES, IF
NECESSARY FOR A 1.0
VOLT DIFFERENCE OR
MORE.
WAS THERE MORE
THAN A 1.0 VOLT
DIFFERENCE?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
ALLOW THE ENGINE
TO RETURN TO IDLE
SPEED.
TURN ENGINE OFF.
IGNITION KEY ON.
*Perform Verification TEST VER-3A.
ERASE TROUBLE
CODES.
PERFORM TEST
CH-1A.
**Check connectors - Clean / repair as necessary.
49
T TEST TC-10A REPAIRING - AUTO SHUTDOWN RELAY CONTROL CIRCUIT
R
O Perform TEST DTC Before Proceeding
TJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
50
TEST TC-10A
REPAIRING - AUTO SHUTDOWN RELAY CONTROL CIRCUIT
Perform TEST DTC Before Proceeding
START TEST
TC-10A.
USING THE DRB,
ACTUATE THE AUTO
SHUTDOWN (ASD)
RELAY.
IS THE ASD RELAY
CLICKING?
NO
CONTINUE TEST
TC-10A ON THE
NEXT PAGE.
C
O
D
E
YES
THE CONDITION
REQUIRED TO SET
THE TROUBLE CODE
IS NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
START THE ENGINE.
WIGGLE THE WIRING
HARNESS FROM THE
RELAY TO THE
POWERTRAIN CONTROL
MODULE.
DID THE ENGINE
STALL WHEN
WIGGLING THE
WIRES?
YES
REPAIR CIRCUIT AS
NECESSARY WHERE
WIGGLING CAUSED
THE ENGINE TO
STALL.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
51
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-10A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - AUTO SHUTDOWN RELAY CONTROL CIRCUIT
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
52
TEST TC-10A
CONTINUED - REPAIRING - AUTO SHUTDOWN RELAY CONTROL CIRCUIT
TEST TC-10A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE
AUTO SHUTDOWN
(ASD) RELAY.**
T
R
O
U
B
L
E
C
O
D
E
KEY ON. USING A
VOLTMETER, MEASURE
THE FUSED IGN SWITCH
OUTPUT CKT AT RELAY.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUSED
IGNITION SWITCH
OUTPUT CIRCUIT FOR
AN OPEN.*
YES
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE BETWEEN
TERMINALS 85 AND
86 OF THE ASD
RELAY. FIG. 3 OR 4
IS THE RESISTANCE
BETWEEN 65 AND 85
OHMS?
NO
REPLACE ASD
RELAY.*
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE ASD
RLY CONTROL
CIRCUIT AT PCM TO
GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE ASD
RELAY CONTROL CKT
FOR A SHORT TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
ASD RELAY CONTROL
CIRCUIT...
BETWEEN THE RELAY
AND THE PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE ASD
RELAY CONTROL CKT
FOR AN OPEN.*
FIG. 1 OR 2
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
53
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-11A
REPAIRING - GENERATOR FIELD NOT SWITCHING PROPERLY
Perform TEST DTC Before Proceeding
TJXJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
54
TEST TC-11A
T
R
O
U
B
L
E
REPAIRING - GENERATOR FIELD NOT SWITCHING PROPERLY
Perform TEST DTC Before Proceeding
START TEST
TC-11A.
DISCONNECT THE
GENERATOR FIELD
HARNESS
CONNECTOR.**
USING THE DRB,
ACTUATE THE
GENERATOR FIELD
DRIVER CIRCUIT.
C
O
D
E
USING A TEST LIGHT
CONNECTED TO
GROUND...
PROBE THE
GENERATOR FIELD
SOURCE (+) CKT.
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE
GENERATOR FIELD
SOURCE (+) CIRCUIT
FOR AN OPEN.*
FIG. 1
YES
USING A TEST LIGHT
CONNECTED TO
BATTERY (+)
VOLTAGE...
PROBE THE GEN FIELD
DRIVER CIRCUIT.
NOTES: DRB STILL
ACTUATING.
FIG. 1
DOES THE TEST
LIGHT FLASH ON AND
OFF?
NO
CONTINUE TEST
TC-11A ON THE
NEXT PAGE.
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 2
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
WITH THE DRB, READ
CODES. NOTE:
ACTUATOR TEST
SHOULD STILL BE
RUNNING.
DOES THE GENERATOR
FIELD NOT SWITCH
PROPERLY CODE
RETURN?
WIGGLE WIRING
HARNESS FROM THE
GENERATOR TO PCM.
YES
REPAIR AS
NECESSARY WHERE
WIGGLING CAUSED
PROBLEM TO
APPEAR.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFOMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-3A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
55
T
E
S
T
S
T
R
O
U
B
L
E
TEST TC-11A
CONTINUED - REPAIRING - GENERATOR FIELD NOT SWITCHING PROPERLY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
56
TEST TC-11A
CONTINUED - REPAIRING - GENERATOR FIELD NOT SWITCHING PROPERLY
TEST TC-11A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
STOP THE GENERATOR
FIELD DRIVER
ACTUATION.
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
KEY OFF.
DISCONNECT THE
POWERTRAIN CONTROL
MODULE.**
USE A OHMMETER IN
THE FOLLOWING
STEPS.
MEASURE RESISTANCE
OF THE GEN FIELD
DRIVER CKT, BETWEEN
GEN FIELD CONN TO
PCM CONN. FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR GENERATOR
FIELD DRIVER
CIRCUIT FOR AN
OPEN.*
YES
MEASURE RESISTANCE
ACROSS THE GENERATOR
FIELD TERMINALS AT
GENERATOR.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR OR REPLACE
THE GENERATOR AS
NECESSARY.*
YES
MEASURE THE GEN
FIELD DRIVER CIRCUIT
AT GENERATOR HARNESS
CONN TO GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
GENERATOR FIELD
DRIVER CIRCUIT FOR
A SHORT TO
GROUND.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
57
T TEST TC-12A REPAIRING TORQUE CONVERTER CLUTCH/TRANS RELAY CKT (TJ/XJ BODY WITH
3SPD AUTO TRANS)
R
Perform
TEST
DTC
Before Proceeding
O
TJ/XJ BODY WITH 3 SPD AUTO TRANS
U
B
L
E
C
O
D
E
T
E
S
T
S
TJ/XJ BODY WITH 3
SPD AUTO TRANS
FIG. 1
TJ/XJ BODY WITH 3
SPD AUTO TRANS
FIG. 2
58
REPAIRING TORQUE CONVERTER CLUTCH/TRANS RELAY CKT (TJ/XJ BODY WITH
3SPD AUTO TRANS)
Perform TEST DTC Before Proceeding
TEST TC-12A
IS THIS VEHICLE
EQUIPPED WITH A 4
SPEED AISIN
TRANSMISSIONS?
START TEST
TC-12A.
YES
REFER TO THE
APPORPERITE
TRANSMISSION
DIAGNOSTIC
MANUAL.
C
O
D
E
NO
DISCONNECT THE
TORQUE CONVERTER
CLUTCH
CONNECTOR.**
KEY ON.
T
E
S
T
S
MEASURE THE VOLTAGE
AT THE FUSED
IGNITION SWITCH
OUTPUT CIRCUIT.
FIG. 1
IS THE VOLTAGE
BELOW 10.0 VOLTS?
YES
REPAIR FUSED
IGNITON SWITCH
OUTPUT FOR AN
OPEN.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE THE
RESISTANCE BETWEEN
THE TCC SOLENOID
CONTROL CIRCUIT...
AND GROUND.
IS RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE TCC
SOLENOID CONTROL
CIRCUIT FOR A
SHORT TO GROUND.*
FIG. 1
NO
MEASURE THE
RESISTANCE OF THE
TCC SOLENOID
CONTROL CIRCUIT
FROM...
THE POWERTRAIN
CONTROL MODULE TO
THE TCC SOLENOID
HARNESS CONNECTORS.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR TCC
SOLENOID CONTROL
CIRCUIT FOR AN
OPEN.*
YES
CONNECT THE TCC
SOLENOID HARNESS
CONNECTOR.
KEY ON.
T
R
O
U
B
L
E
MEASURE THE VOLTAGE
OF THE TCC SOLENOID
CONTROL CIRCUIT AT
PCM CONNECTOR.
FIG. 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPLACE TCC
SOLENOID.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
59
T TEST TC-14A REPAIRING - RADIATOR FAN RELAY CIRCUIT
R
O Perform TEST DTC Before Proceeding
XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
60
TEST TC-14A
REPAIRING - RADIATOR FAN RELAY CIRCUIT
Perform TEST DTC Before Proceeding
START TEST
TC-14A.
USING THE DRB,
ACTUATE THE
RADIATOR FAN.
IS THE FAN CYCLING
ON AND OFF?
NO
CONTINUE TEST
ON THE NEXT
PAGE
C
O
D
E
YES
THE CONDITION TO SET
THE TROUBLE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
WIGGLE THE WIRING
HARNESS FROM THE
RELAY TO THE PCM.
NOTE: THE DRB MUST
STILL BE ACTUATING
THE FAN RELAY.
DID THE WIGGLING
INTERUPT THE FAN
CYCLING?
YES
REPAIR AS
NECESSARY WHERE
WIGGLING CAUSED
FAN CYCLING TO BE
INTERUPTED.*
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETED.*
**Check connectors - Clean / repair as necessary.
61
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-14A
R
O
XJ BODY
U
B
L
E
CONTINUED - REPAIRING - RADIATOR FAN RELAY CIRCUIT
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
XJ BODY
FIG. 3
62
TEST TC-14A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - RADIATOR FAN RELAY CIRCUIT
TEST TC-14A
CONTINUED FROM
THE PREVIOUS
PAGE.
REMOVE THE
RADIATOR FAN
RELAY.**
C
O
D
E
TURN IGNITION ON.
USING A VOLTMETER,
MEASURE THE FUSED
IGNITION SWITCH
OUTPUT CIRCUIT.
FIG. 1
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUSED
IGNITION SWITCH
OUTPUT CIRCUIT FOR
AN OPEN.*
YES
TURN THE IGNITION
OFF. USE AN
OHMMETER IN THE
FOLLOWING STEPS.
MEASURE THE
RESISTANCE BETWEEN
TERMINALS 85 AND
86 OF THE RADIATOR
FAN RELAY FIG. 2
IS THE RESISTANCE
BETWEEN 60 TO 80
OHMS?
NO
REPLACE THE
RADIATOR FAN
RELAY.*
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE THE
RESISTANCE BETWEEN
GND AND CAV 85 OF
THE RELAY HARNESS
CONNECTOR. FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
RADIATOR FAN
CONTROL RELAY
CIRCUIT FOR A
SHORT TO GROUND.*
NO
MEASURE THE
RESISTANCE OF THE
RADIATOR FAN RELAY
CONTROL CIRCUIT...
FROM THE RELAY
CONNECTOR TO PCM
HARNESS CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR OPEN
RADIATOR FAN RELAY
CONTROL CIRCUIT.*
FIG. 3
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
63
T
E
S
T
S
T TEST TC-15A REPAIRING - SPEED CONTROL CIRCUITS
R
O Perform TEST DTC Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
XJ BODY
FIG. 2
FIG. 3
TJ BODY
XJ BODY
FIG. 4
FIG. 5
64
TEST TC-15A
T
R
O
U
B
L
E
REPAIRING - SPEED CONTROL CIRCUITS
Perform TEST DTC Before Proceeding
START TEST
TC-15A.
A MISAJUSTED BRAKE
SWITCH CAN CAUSE
THIS CODE TO SET.
CHECK BRAKE SWITCH
ADJUSTMENT BEFORE
CONTINUING.
C
O
D
E
DISCONNECT THE
SPEED CONTROL
SERVO 4-WAY
HARNESS
CONNECTOR.**
USING A VOLTMETER,
MEASURE THE S/C
BRAKE SWITCH
OUTPUT CIRCUIT
AT...
NOTE: ENSURE THE
BRAKE PEDAL IS NOT
DEPRESSED DURING
THE FOLLOWING
STEPS.
ENGINE OFF.
TURN IGNITION ON.
SPEED CONTROL
SWITCH ON.
THE SPEED CONTROL
SERVO HARNESS
CONNECTOR.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
T
E
S
T
S
YES
PERFORM TEST
TC-15B.
YES
CONTINUE TEST
TC-15A ON NEXT
PAGE.
FIG. 1
NO
DISCONNECT THE
BRAKE LAMP SWITCH
CONNECTOR.**
USING A VOLTMETER,
MEASURE THE
12-VOLT SUPPLY
CIRCUIT.
FIG. 2 OR 3
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE
12-VOLT SUPPLY
CIRCUIT TO GROUND.
FIG. 2 OR 3
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
12-VOLT SUPPLY
CIRCUIT.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
12-VOLT SUPPLY
CIRCUIT. FIG. 4 OR 5
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE 12-VOLT SUPPLY
CIRCUIT.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
65
T TEST TC-15A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL CIRCUITS
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
66
TEST TC-15A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL CIRCUITS
TEST TC-15A
CONTINUED FROM
THE PREVIOUS
PAGE.
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
C
O
D
E
MEASURE BETWEEN
BRAKE LAMP SWITCH
HARNESS CONNECTOR
CAVITY 4 AND GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
S/C BRAKE SWITCH
OUTPUT CIRCUIT.*
NO
MEASURE THE
RESISTANCE OF THE
S/C BRAKE SWITCH
OUTPUT CIRCUIT.
FIG. 3 OR 4
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE BRAKE
LAMP SWITCH.*
NO
REPAIR THE OPEN IN
THE S/C BRAKE
SWITCH OUTPUT
CIRCUIT.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
67
T
E
S
T
S
T TEST TC-15B REPAIRING - SPEED CONTROL CIRCUITS
R
O Perform TEST TC-15A Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
68
TEST TC-15B
T
R
O
U
B
L
E
REPAIRING - SPEED CONTROL CIRCUITS
Perform TEST TC-15A Before Proceeding
START TEST
TC-15B.
TURN IGNITION OFF.
C
O
D
E
USING AN OHMMETER,
MEASURE THE GROUND
CIRCUIT AT...
THE S/C SERVO 4-WAY
HARNESS CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
SERVO GROUND
CIRCUIT.*
FIG. 1
YES
WITH AN OHMMETER,
PERFORM THE
FOLLOWING
MEASUREMENTS TO
GROUND.
SPEED CONTROL VENT
SOL CKT AND SPEED
CONTROL VACUUM SOL
CKT.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS FOR
EITHER
MEASUREMENT?
YES
REPAIR THE
CIRCUIT(S) THAT
MEASURED BELOW 5.0
OHMS FOR A SHORT
TO GROUND.*
NO
RECONNECT THE S/C
SERVO HARNESS
CONNECTOR.
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE BETWEEN PCM
HARNESS CONNECTOR
CAVITIES C11 AND C5.
IS THE RESISTANCE
BETWEEN
NO
CONTINUE TEST
TC-15B ON THE
NEXT PAGE.
NO
CONTINUE TEST
TC-15B ON THE
NEXT PAGE.
35.0 AND 55.0
OHMS?
FIG. 2
YES
MEASURE BETWEEN PCM
HARNESS CONNECTOR
CAVITIES C11 AND C4.
IS THE RESISTANCE
BETWEEN
FIG. 2
35.0 AND 55.0
OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
69
T
E
S
T
S
T TEST TC-15B
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL CIRCUITS
C
O
D
E
T
E
S
T
S
FIG. 1
70
TEST TC-15B
T
R
O
U
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL CIRCUITS
TEST TC-15B
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE S/C
SERVO 4-WAY
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE THE S/C
VACUUM SOLENOID
CONTROL CIRCUIT...
BETWEEN THE S/C
SERVO AND PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
S/C VACUUM
SOLENOID CONTROL
CIRCUIT.*
FIG. 1
YES
USING AN OHMMETER,
MEASURE THE S/C
VENT SOLENOID
CONTROL CIRCUIT...
BETWEEN THE S/C
SERVO AND PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REAPIR THE OPEN
S/C VENT SOLENOID
CONTROL CIRCUIT.*
YES
REPLACE THE SPEED
CONTROL SERVO.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
71
T
E
S
T
S
T TEST TC-16A REPAIRING - A/C CLUTCH RELAY CIRCUIT
R
O Perform TEST DTC Before Proceeding
TJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
72
TEST TC-16A
REPAIRING - A/C CLUTCH RELAY CIRCUIT
Perform TEST DTC Before Proceeding
START TEST
TC-16A.
KEY ON. USING THE
DRB, ACTUATE THE
A/C CLUTCH RELAY.
IS THE A/C CLUTCH
RELAY CLICKING?
NO
CONTINUE TEST
TC-16A ON THE
NEXT PAGE.
YES
THE CONDITION
REQUIRED TO SET
THE TROUBLE CODE
IS NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
WIGGLE THE WIRING
HARNESS FROM THE
RELAY TO THE
POWERTRAIN CONTROL
MODULE.
NOTE: THE DRB MUST
STILL BE ACTUATING
THE A/C CLUTCH
RELAY.
DID THE WIGGLING
INTERRUPT THE
CLICKING?
YES
REPAIR AS
NECESSARY WHERE
WIGGLING CAUSED
THE CLICKING TO BE
INTERRUPTED.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
73
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-16A
R
O
TJ BODY
U
B
L
E
CONTINUED - REPAIRING A/C CLUTCH RELAY CIRCUIT
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
FIG. 3
74
TEST TC-16A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - A/C CLUTCH RELAY CIRCUIT
TEST TC-16A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE A/C
CLUTCH RELAY.**
C
O
D
E
KEY ON. USING A
VOLTMETER, MEASURE
THE FUSED IGN
SWITCH OUTPUT CKT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUSED
IGNITION SWITCH
OUTPUT CIRCUIT FOR
AN OPEN.*
NO
REPLACE THE A/C
CLUTCH RELAY.*
YES
KEY OFF. USE AN
OHMMETER IN THE
FOLLOWING STEP.
MEASURE THE
RESISTANCE BETWEEN
TERMINALS 85 AND 86
OF THE A/C CLUTCH
RELAY. FIG. 3
IS THE RESISTANCE
BETWEEN 70 AND 90
OHMS?
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE A/C
CLUTCH CONTROL CKT
AT PCM TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE A/C
CLUTCH RELAY
CONTROL CIRCUIT
FOR A SHORT TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
A/C CLUTCH RELAY
CONTROL CIRCUIT...
BEWTEEN THE RELAY
AND THE PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE A/C
CLUTCH RELAY
CONTROL CIRCUIT
FOR AN OPEN.*
FIG. 1 OR 2
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
75
T
E
S
T
S
T TEST TC-18A REPAIRING - EVAP PURGE SOLENOID CIRCUIT
R
O Perform TEST DTC Before Proceeding
XJ BODY
U TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
TJ BODY
XJ BODY
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
76
TEST TC-18A
REPAIRING - EVAP PURGE SOLENOID CIRCUIT
Perform TEST DTC Before Proceeding
START TEST
TC-18A.
USING THE DRB,
ACTUATE THE EVAP
SLOENOID.
IS THE EVAP
SOLENOID CLICKING?
YES
CONTINUE TEST
TC-18A ON THE
NEXT PAGE.
C
O
D
E
NO
DISCONNECT THE
EVAP SOLENOID
HARNESS
CONNECTOR.**
KEY ON. USING A
VOLTMETER, MEASURE
THE FUSED IGNITION
SW OUTPUT CIRCUIT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN IN
THE FUSED IGNITION
SWITCH OUTPUT
CIRCUIT.*
YES
NOTE: DRB STILL
ACTUATING THE EVAP
SOLENOID.
USING A TEST LIGHT,
CONNECT ONE END OF
THE TEST LIGHT TO
THE FUSED IGN SW
OUTPUT CIRCUIT ...
THE OTHER END TO THE
EVAP SOL CONTROL CKT
AT THE EVAP SOLENOID
HARNESS CONNECTOR.
FIG. 1 OR 2
DOES THE TEST
LIGHT FLASH ON AND
OFF?
YES
CONTINUE TEST
TC-18A ON THE
NEXT PAGE.
NO
STOP THE SOLENOID
FROM ACTUATING.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF EVAP
SOLENOID CONTROL
CKT. FIG. 3 OR 4
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE EVAP SOLENOID
CONTROL CIRCUIT.*
YES
USING AN OHMMETER,
MEASURE THE EVAP
SOLENOID CONTROL
CKT TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
EVAP SOLENOID
CONTROL CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
77
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-18A
R
O
U
B
L
E
CONTINUED - REPAIRING - EVAP PURGE SOLENOID CIRCUIT
C
O
D
E
T
E
S
T
S
FIG. 1
78
TEST TC-18A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - EVAP PURGE SOLENOID CIRCUIT
TEST TC-18A
CONTINUED FROM
THE PREVIOUS
PAGE.
STOP ACTUATION OF
THE EVAP SOLENOID.
DISCONNECT THE
VACUUM HOSES FROM
THE EVAP SOLENOID.
BLOW LIGHT AIR
INTO THE TOP
VACUUM PORT OF THE
EVAP SOLENOID.
FIG. 1
C
O
D
E
DOES THE AIR BLOW
OUT THE BOTTOM
VACUUM PORT?
YES
REPLACE THE EVAP
SOLENOID.*
NO
REPLACE THE EVAP
SOLENOID.
NO
USING THE DRB,
ACTUATE THE EVAP
SOLENOID.
BLOW LIGHT AIR
INTO THE TOP
VACUUM PORT OF THE
EVAP SOLENOID.
FIG. 1
DOES THE AIR BLOW
OUT THE BOTTOM
VACUUM PORT?
YES
INSPECTED THE EVAP
LINES FOR BEING
PLUGGED, PINCHED,
CUTS, MISROUTING.
ARE THE EVAP LINES
OK?
NO
REPAIR AS
NECESSARY.*
YES
CONTINUE TEST
TC-18A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
79
T
E
S
T
S
T TEST TC-18A
R
O
U
B
L
E
CONTINUED - REPAIRING - EVAP PURGE SOLENOID CIRCUIT
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
XJ BODY
80
TEST TC-18A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - EVAP PURGE SOLENOID CIRCUIT
TEST TC-18A
CONTINUED.FROM
THE PREVIOUS
PAGE.
RECONNECT THE
VACUUM HOSES.
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
REFER TO GEN INFO
3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEM
FOUND?
C
O
D
E
YES
REPAIR AS
NECESSARY.*
NO
WITH THE DRB, READ
CODES. NOTE:
ACTUATE THE EVAP
SOLENOID.
WIGGLE WIRING
HARNESS FROM THE
SOLENOID TO THE
PCM.
DOES THE EVAP
SOLENOID EVER STOP
ACTUATING.
YES
REPAIR AS
NECESSARY WHERE
WIGGLING CAUSED
PROBLEM TO APPEAR.
NO
TEST COMPLETE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
81
T
E
S
T
S
T TEST TC-19A REPAIRING - INJECTOR #3 CONTROL CIRCUIT
R
O Perform TEST TC-21A Before Proceeding
4.0L
U 2.5L
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
2.5L
4.0L
FIG. 3
FIG. 4
82
TEST TC-19A
T
R
O
U
B
L
E
REPAIRING - INJECTOR #3 CONTROL CIRCUIT
Perform TEST TC-21A Before Proceeding
START TEST
TC-19A
KEY OFF.
DISCONNECT THE
INJECTOR #3
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE RESISTANCE
OF INJECTOR #3.
IS THE RESISTANCE
BETWEEN 10.0 AND
16.0 OHMS?
NO
REPLACE THE FUEL
INJECTOR.*
YES
KEY ON. USING THE
DRB, ACTUATE THE
AUTO SHUTDOWN
RELAY.
USING A TEST LIGHT
CONNECTED, PROBE
THE ASD RELAY
OUTPUT CIRCUIT.
FIG. 1 OR 2
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
WITH THE ASD RELAY
STILL ACTUATING,
USING A VOLTMETER
MEASURE THE INJECTOR
DRIVER CIRCUIT...
BETWEEN THE
INJECTOR HARNESS
CONNECTOR AND
GROUND.
IS THE VOLTAGE
ABOVE 1.0 VOLTS?
YES
REPAIR THE INJECTOR
#3 DRIVER CIRCUIT
FOR A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
INJECTOR #3 DRIVER
CIRCUIT TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
INJECTOR #3 DRIVER
CIRCUIT FOR A
SHORT TO GROUND.*
NO
WITH AN OHMMETER,
MEASURE ACROSS THE
INJECTOR #3 DRIVER
CIRCUIT.
FIG. 3 OR 4
FROM THE
POWERTRAIN CONTROL
MODULE TO THE
INJECTOR
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
INJECTOR #3 DRIVER
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
83
T
E
S
T
S
T TEST TC-20A REPAIRING - INJECTOR #2 CONTROL CIRCUIT
R
O Perform TEST TC-21A Before Proceeding
4.0L
U 2.5L
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
2.5L
4.0L
FIG. 3
FIG. 4
84
TEST TC-20A
T
R
O
U
B
L
E
REPAIRING - INJECTOR #2 CONTROL CIRCUIT
Perform TEST TC-21A Before Proceeding
START TEST
TC-20A
KEY OFF.
DISCONNECT THE
INJECTOR #2
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE RESISTANCE
OF INJECTOR #2.
IS THE RESISTANCE
BETWEEN 10.0 AND
16.0 OHMS?
NO
REPLACE THE FUEL
INJECTOR.*
YES
KEY ON. USING THE
DRB, ACTUATE THE
AUTO SHUTDOWN
RELAY.
USING A TEST LIGHT
CONNECTED TO GROUND,
PROBE THE ASD RELAY
OUTPUT CIRCUIT.
FIG. 1 OR 2
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
WITH THE ASD RELAY
STILL ACTUATED,USING
A VOLTMETER, MEASURE
THE INJECTOR DRIVER
CIRCUIT...
BETWEEN THE
INJECTOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 1.0 VOLTS?
YES
REPAIR THE INJECTOR
#2 DRIVER CIRCUIT
FOR A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
INJECTOR #2 DRIVER
CIRCUIT TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
INJECTOR # DRIVER
CIRCUIT FOR A
SHORT TO GROUND.*
NO
WITH AN OHMMETER,
MEASURE ACROSS THE
INJECTOR #2 DRIVER
CIRCUIT.
FIG. 3 OR 4
FROM THE
POWERTRAIN CONTROL
MODULE TO THE
INJECTOR
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
INJECTOR #2 DRIVER
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
85
T
E
S
T
S
T TEST TC-21A REPAIRING - INJECTOR CONTROL CIRCUITS
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
2.5L
4.0L
86
TEST TC-21A
T
R
O
U
B
L
E
REPAIRING - INJECTOR CONTROL CIRCUITS
Perform TEST DTC Before Proceeding
START TEST
TC-21A
KEY ON, ENGINE
OFF.
START THE ENGINE,
LET IDLE FOR AT
LEAST 20 SECOND.
C
O
D
E
DOES THE DRB
DISPLAY ANY
"INJECTOR CONTROL
CIRCUIT" CODE(S)?
WITH THE DRB, READ
TROUBLE CODES.
YES
CONTINUE TEST
TC-21A ON THE
NEXT PAGE.
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
START ENGINE.
WIGGLE WIRING
HARNESS FROM THE
INJECTOR TO THE
PCM.
DOES THE ENGINE
MISS OR STALL?
YES
REPAIR AS
NECESSARY WHERE
WIGGLING CAUSED
PROBLEM TO
APPEAR.*
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
87
T
E
S
T
S
T TEST TC-21A
R
O
U
B
L
E
CONTINUED - REPAIRING - INJECTOR CONTROL CIRCUITS
NOTES
C
O
D
E
T
E
S
T
S
88
TEST TC-21A
CONTINUED - REPAIRING - INJECTOR CONTROL CIRCUITS
Refer to the chart below and perform the diagnostic test that corresponds to the trouble code
displayed on the DRB.
TROUBLE CODE
INJECTOR
INJECTOR
INJECTOR
INJECTOR
INJECTOR
INJECTOR
#1
#2
#3
#4
#5
#6
DIAGNOSTIC TEST
CONTROL CIRCUIT
CONTROL CIRCUIT
CONTROL CIRCUIT
CONTROL CIRCUIT
CONTROL CIRCUIT
CONTROL CIRCUIT
TC-21B
TC-20A
TC-19A
TC-61A
TC-69A
TC-70A
89
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-21B REPAIRING - INJECTOR #1 CONTROL CIRCUIT
R
O Perform TEST TC-21A Before Proceeding
4.0L
U 2.5L
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
2.5L
4.0L
FIG. 3
FIG. 4
90
TEST TC-21B
T
R
O
U
B
L
E
REPAIRING - INJECTOR #1 CONTROL CIRCUIT
Perform TEST TC-21A Before Proceeding
START TEST
TC-21B
KEY OFF.
DISCONNECT THE
INJECTOR #1
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE RESISTANCE
OF INJECTOR #1.
IS THE RESISTANCE
BETWEEN 10.0 AND
16.0 OHMS?
NO
REPLACE THE FUEL
INJECTOR.*
YES
KEY ON. USING THE
DRB, ACTUATE THE
AUTO SHUTDOWN
RELAY.
USING A TEST LIGHT
CONNECTED TO GROUND,
PROBE THE ASD RELAY
OUTPUT CIRCUIT.
FIG. 1 OR 2
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
WITH THE ASD RELAY
STILL ACTUATED,
USING A VOLTMETER,
MEASURE THE INJECTOR
DRIVER CIRCUIT...
BETWEEN THE
INJECTOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 1.0 VOLTS?
YES
REPAIR THE INJECTOR
#1 DRIVER CIRCUIT
FOR A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
INJECTOR #1 DRIVER
CIRCUIT TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
INJECTOR #1 DRIVER
CIRCUIT FOR A
SHORT TO GROUND.*
NO
WITH AN OHMMETER,
MEASURE ACROSS THE
INJECTOR #1 DRIVER
CIRCUIT.
FIG. 3 OR 4
FROM THE
POWERTRAIN CONTROL
MODULE TO THE
INJECTOR
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
INJECTOR #1 DRIVER
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
91
T
E
S
T
S
T TEST TC-25A REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
R
O Perform TEST DTC Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
92
TEST TC-25A
T
R
O
U
B
L
E
REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
Perform TEST DTC Before Proceeding
START TEST
TC-25A
TURN IGNITION OFF
FOR 10 SECONDS.
START ENGINE,
ALLOW TO IDLE FOR
20 SECONDS.
C
O
D
E
NOTE:
IF ENGINE WILL NOT
IDLE, HOLD THROTTLE
OPEN SLIGHTLY TO
KEEP ENGINE RUNNING.
WITH THE DRB,
ACTUATE THE IDLE
AIR CONTROL MOTOR
TO 1400 RPM.
NOTE:
RELEASE THROTTLE.
NO
CONTINUE TEST
TC-25A ON THE
NEXT PAGE.
NO
CONTINUE TEST
TC-25A ON THE
NEXT PAGE.
IS THE ENGINE SPEED
1400 +/- 100 RPM?
YES
WITH THE DRB,
ACTUATE THE IDLE
AIR CONTROL MOTOR
TO 900 RPM.
IS THE ENGINE
SPEED 900 +/- 100
RPM?
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
START ENGINE. WITH
THE DRB IN SYSTEMS
TESTS, PERFORM THE
IAC WIGGLE TEST.
THE IDLE SPEED
SHOULD RAISE AND
LOWER WITH THE
DISPLAY.
DOES THE IDLE
SPEED RAISE AND
LOWER PROPERLY?
NO
CONTINUE TEST
TC-25A ON THE
NEXT PAGE.
YES
WIGGLE THE WIRING
HARNESS FROM THE
IAC MOTOR TO THE
PCM.
OBSERVE FOR THE
IAC MOTOR TO STOP
OPERATING.
DID THE IAC STOP
OPERATING AT ANY
TIME?
YES
REPAIR THE HARNESS
OR CONNECTORS AS
NECESSARY.*
NO
WITH THE DRB, STOP
THE IAC WIGGLE
TEST.
REFER TO GEN INFO
3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
93
T
E
S
T
S
T TEST TC-25A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
C
O
D
E
T
E
S
T
S
94
TEST TC-25A
CONTINUED - REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
TEST TC-25A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
STOP ALL TESTS.
T
R
O
U
B
L
E
C
O
D
E
TURN IGNITION OFF.
DISCONNECT IAC
MOTOR HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE BETWEEN...
..IAC DRIVER #1
AND GROUND.
T
E
S
T
S
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE IAC #1
DRIVER CIRCUIT
SHORTED TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE BETWEEN...
..IAC DRIVER #2
AND GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE IAC #2
DRIVER CIRCUIT
SHORTED TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE BETWEEN...
..IAC DRIVER #3
AND GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE IAC #3
DRIVER CIRCUIT
SHORTED TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE BETWEEN...
..IAC DRIVER #4
AND GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE IAC #4
DRIVER CIRCUIT
SHORTED TO
GROUND.*
NO
CONTINUE TEST
TC-25A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
95
T TEST TC-25A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
C
O
D
E
T
E
S
T
S
96
TEST TC-25A
CONTINUED - REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
TEST TC-25A
CONTINUED FROM
THE PREVIOUS
PAGE.
START ENGINE AND
LET IDLE.
T
R
O
U
B
L
E
C
O
D
E
USING A VOLTMETER,
MEASURE THE IAC
DRIVER #1 CIRCUIT.
WAS THE VOLTAGE
OVER 5.0 VOLTS AT
ANY TIME?
NO
PERFORM TEST
TC-25B
NO
PERFORM TEST
TC-25C
NO
PERFORM TEST
TC-25D
NO
PERFORM TEST
TC-25E
YES
USING A VOLTMETER,
MEASURE THE IAC
DRIVER #2 CIRCUIT.
WAS THE VOLTAGE
OVER 5.0 VOLTS AT
ANY TIME?
YES
USING A VOLTMETER,
MEASURE THE IAC
DRIVER #3 CIRCUIT.
WAS THE VOLTAGE
OVER 5.0 VOLTS AT
ANY TIME?
YES
USING A VOLTMETER,
MEASURE THE IAC
DRIVER #4 CIRCUIT.
WAS THE VOLTAGE
OVER 5.0 VOLTS AT
ANY TIME?
YES
CONTINUE TEST
TC-25A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
97
T
E
S
T
S
T TEST TC-25A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
C
O
D
E
T
E
S
T
S
98
TEST TC-25A
CONTINUED - REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
TEST TC-25A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF,
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
C
O
D
E
NO
THE FOLLOWING
STEPS ARE CHECKING
FOR A SHORT
BETWEEN THE DRIVER
CIRCUITS...
T
E
S
T
S
...USING AN
OHMMETER, MEASURE
THE RESISTANCE
BETWEEN THE ...
IS THE RESISTANCE
BELOW 5.0 OHMS ON
ANY OF THE
DRIVERS?
...IAC #1 DRIVER
AND #2,#3,#4
DRIVERS.
YES
REPAIR THE IAC
DRIVER CIRCUITS,
SHORTED TOGETHER.*
YES
REPAIR THE IAC
DRIVER CIRCUITS,
SHORTED TOGETHER.*
YES
REPAIR THE IAC
DRIVER CIRCUITS,
SHORTED TOGETHER.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE BETWEEN
THE ...
IS THE RESISTANCE
BELOW 5.0 OHMS ON
ANY OF THE
DRIVERS?
...IAC #2 DRIVER
AND #3,#4 DRIVERS.
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE BETWEEN
THE ...
...IAC #3 DRIVER
AND #4 DRIVER.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE IDLE
AIR CONTROL
MOTOR.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
99
T TEST TC-25B REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
R
O Perform TEST TC-25A Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
100
TEST TC-25B
REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
Perform TEST TC-25A Before Proceeding
START TEST
TC-25B.
KEY OFF,
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
C
O
D
E
NO
MEASURE RESISTANCE
OF THE IAC #1
DRIVER CIRCUIT
BETWEEN PCM & IAC.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE OPEN
IDLE AIR CONTROL
MOTOR DRIVER
CIRCUIT.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
101
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-25C REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
R
O Perform TEST TC-25A Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
102
TEST TC-25C
REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
Perform TEST TC-25A Before Proceeding
START TEST
TC-25C.
KEY OFF, DISCONNECT
THE POWERTRAIN
CONTROL MODULE
HARNESS CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
C
O
D
E
NO
MEASURE RESISTANCE
OF THE IAC #2
DRIVER CIRCUIT
BETWEEN PCM & IAC.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE OPEN
IDLE AIR CONTROL
MOTOR DRIVER
CIRCUIT.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
103
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-25D REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
R
O Perform TEST TC-25A Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
104
TEST TC-25D
REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
Perform TEST TC-25A Before Proceeding
START TEST
TC-25D.
KEY OFF, DISCONNECT
THE POWERTRAIN
CONTROL MODULE
HARNESS CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
C
O
D
E
NO
MEASURE RESISTANCE
OF THE IAC #3
DRIVER CIRCUIT
BETWEEN PCM & IAC.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE OPEN
IDLE AIR CONTROL
MOTOR DRIVER
CIRCUIT.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
105
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-25E REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
R
O Perform TEST TC-25A Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
106
TEST TC-25E
REPAIRING - IDLE AIR CONTROL MOTOR CIRCUITS
Perform TEST TC-25A Before Proceeding
START TEST
TC-25E.
KEY OFF, DISCONNECT
THE POWERTRAIN
CONTROL MODULE
HARNESS CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
C
O
D
E
NO
MEASURE RESISTANCE
OF THE IAC #4
DRIVER CIRCUIT
BETWEEN PCM & IAC.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE OPEN
IDLE AIR CONTROL
MOTOR DRIVER
CIRCUIT.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
107
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-26A REPAIRING - THROTTLE POSITION SENSOR VOLTAGE LOW
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
108
TEST TC-26A
REPAIRING - THROTTLE POSITION SENSOR VOLTAGE LOW
Perform TEST DTC Before Proceeding
START TEST
TC-26A.
KEY ON. USING THE
DBR, READ THE
THROTTLE POSITION
(TP) SENSOR
VOLTAGE.
IS THE TP SNESOR
VOLTAGE BELOW 0.2
VOLTS?
YES
CONTINUE TEST
TC-26A ON THE
NEXT PAGE.
C
O
D
E
NO
OBSERVING THE DRB,
SLOWLY OPEN AND
CLOSE THE
THROTTLE.
IS THE TP SENSOR
VOLTAGE CHANGE
SMOOTH?
NO
REPLACE THE
THROTTLE POSITION
SENSOR.*
YES
WIGGLE THE TP
SENSOR CONNECTORS
AND WIRING
HARNESS.
WAS THERE ANY
CHANGE IN THROTTLE
POSITION SENSOR
VOLTAGE WHEN
WIGGLED?
OBSERVE THE DRB
DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
START THE ENGINE.
WIGGLE THE TP
SENSOR CONNECTORS
AND HARNESS.
WAS THERE ANY
CHANGE IN THE
ENGINE RPM WHILE
WIGGLEING THE TP
SENSOR HARNESS?
MONITOR THE ENGINE
RPM.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE ENGINE
RPM TO CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
THE PROBLEM DOES
NOT EXSIST AT THIS
TIME.
FIG. 1
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
109
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-26A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - THROTTLE POSITION SENSOR VOLTAGE LOW
C
O
D
E
T
E
S
T
S
FIG. 1
110
TEST TC-26A
CONTINUED - REPAIRING - THROTTLE POSITION SENSOR VOLTAGE LOW
TEST TC-26A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF. DISCONNECT
THE THROTTLE
POSITION (TP) SENSOR
HARNESS CONNECTOR.**
T
R
O
U
B
L
E
C
O
D
E
KEY ON. USE A
VOLTMETER IN THE
FOLLOWING STEP.
MEASURE THE TP
SENSOR 5 VOLT
SUPPLY CIRCUIT.
IS THE VOLTAGE
BELOW 4.0 VOLTS?
YES
REPAIR THE TP
SENSOR 5 VOLT
SUPPLY CIRCUIT FOR
AN OPEN.*
FIG. 1
NO
USING THE DRB,
READ THE TP SENSOR
VOLTAGE.
IS THE VOLTAGE
ABOVE 4.0 VOLTS?
YES
REPLACE THE
THROTTLE POSITION
SENSOR.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE BETWEEN THE
TP SENSOR SIGNAL
CIRCUIT AND GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
THROTTLE POSITION
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE...
BETWEEN THE SENSOR
SIGNAL CKT AND THE
SENSOR GROUND CKT.
IS THE RESISTANCE
BELOW 5.0 OHMS?
FIG. 1
YES
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO THE
SENSOR GROUND
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
111
T
E
S
T
S
T TEST TC-27A REPAIRING - THROTTLE POSITION SENSOR VOLTAGE HIGH
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
112
TEST TC-27A
REPAIRING - THROTTLE POSITION SENSOR VOLTAGE HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-27A.
USING THE DRB,
READ THE THROTTLE
POSITION SENSOR
VOLTAGE.
IS THE THROTTLE
POSITION SENSOR
VOLTAGE ABOVE 4.5
VOLTS?
YES
CONTINUE TEST
TC-27A ON THE
NEXT PAGE.
C
O
D
E
NO
OBSERVING THE DRB,
SLOWLY OPEN AND
CLOSE THE
THROTTLE.
IS THE VOLTAGE
CHANGE SMOOTH?
NO
REPLACE THE
THROTTLE POSITION
SENSOR.*
YES
WIGGLE THROTTLE
POSITON SENSOR
CONNECTORS AND
WIRING HARNESS.
WAS THERE ANY
CHANGE IN THROTTLE
POSITION SENSOR
VOLTAGE WHEN
WIGGLED?
MONITOR THE DRB
DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
113
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-27A
R
O
U
TJ/XJ BODY
B
L
E
CONTINUED - REPAIRING - THROTTLE POSITION SENSOR VOLTAGE HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
114
TEST TC-27A
CONTINUED - REPAIRING - THROTTLE POSITION SENSOR VOLTAGE HIGH
TEST TC-27A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE
THROTTLE POSITION
(TP) SENSOR.**
T
R
O
U
B
L
E
C
O
D
E
KEY ON. USE A
VOLTMETER IN THE
FOLLOWING STEP.
MEASURE THE TP
SENSOR SIGNAL
CIRCUIT VOLTAGE.
FIG. 1
IS THE VOLTAGE
ABOVE 5.5 VOLTS?
REPAIR THE TP SENSOR
YES SIGNAL CIRCUIT FOR A
SHORT TO VOLTAGE. IF
OK, REPLACE PCM.*
NO
CONNECT A JUMPER
WIRE BETWEEN THE TP
SENSOR SIGNAL CKT
AND SENSOR GND CKT.
FIG. 1
DOES THE TP SENSOR
VOLTAGE DROP FROM
5.0 TO LESS THAN
1.0 VOLTS?
YES
REPLACE THE
THROTTLE POSITION
SENSOR.*
NO
MOVE THE JUMPER WIRE
BETWEEN THE SENSOR
SIGNAL CIRCUIT AND
AN ENGINE GROUND.
FIG. 1
DOES THE TP SENSOR
VOLTAGE DROP FROM
5.0 TO LESS 1.0
VOLTS?
OBSERVE THE TP
SENSOR VOLTAGE.
YES
REPAIR THE TP
SENSOR GROUND
CIRCUIT FOR AN
OPEN.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE RESISTANCE
OF THE TP SENSOR
SIGNAL CKT FROM
PCM TO TP SENSOR
CONN. FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE TP
SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
115
T
E
S
T
S
T TEST TC-30A REPAIRING - ECT SENSOR VOLTAGE TOO LOW
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
116
TEST TC-30A
REPAIRING - ECT SENSOR VOLTAGE TOO LOW
Perform TEST DTC Before Proceeding
START TEST
TC-30A.
KEY ON. USING THE
DRB, READ THE
ENGINE COOLANT
TEMPERATURE (ECT)
SENSOR VOLTAGE.
IS THE ECT SENSOR
VOLTAGE BELOW
0.5 VOLTS?
YES
CONTINUE TEST
TC-30A ON THE
NEXT PAGE.
NO
WIGGLE THE ECT
SENSOR CONNECTOR
AND WIRING
HARNESS.
OBSERVE THE DRB
DISPLAY.
DID THE ECT SENSOR
VOLTAGE READING
CHANGE?
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
117
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-30A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - ECT SENSOR VOLTAGE TOO LOW
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
118
TEST TC-30A
CONTINUED - REPAIRING - ECT SENSOR VOLTAGE TOO LOW
TEST TC-30A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF. DISCONNECT
THE ENGINE COOLANT
TEMPERATURE (ECT)
SENSOR CONNECTOR.**
T
R
O
U
B
L
E
C
O
D
E
KEY ON. USING THE
DRB, READ THE ECT
SENSOR VOLTAGE.
IS THE ECT SENSOR
VOLTAGE ABOVE 4.0
VOLTS?
YES
REPLACE THE ENGINE
COOLANT
TEMPERATURE
SENSOR.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE ECT
SENSOR SIGNAL
CIRCUIT TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE BETWEEN
THE...
ECT SENSOR SIGNAL
CIRCUIT AND THE
SENSOR GROUND
CIRCUIT.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE ECT
SENSOR SIGNAL
CIRCUIT FOR A SHORT
TO THE SENSOR GROUND
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
119
T
E
S
T
S
T TEST TC-31A REPAIRING - ECT SENSOR VOLTAGE TOO HIGH
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
120
TEST TC-31A
REPAIRING - ECT SENSOR VOLTAGE TOO HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-31A.
KEY ON. USING THE
DRB, READ THE
ENGINE COOLANT
TEMPERATURE (ECT)
SENSOR VOLTAGE.
IS THE ECT SENSOR
VOLTAGE ABOVE 4.5
VOLTS?
YES
CONTINUE TEST
TC-31A ON THE
NEXT PAGE.
NO
WIGGLE THE ENGINE
COOLANT TEMP
SENSOR CONNECTOR &
HARNESS.
OBSERVE THE DRB
DISPLAY.
DID THE ECT SENSOR
VOLTAGE CHANGE?
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
121
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-31A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - ECT SENSOR VOLTAGE TOO HIGH
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
122
TEST TC-31A
CONTINUED - REPAIRING - ECT SENSOR VOLTAGE TOO HIGH
TEST TC-31A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE
ENGINE COOLANT
TEMPERATURE (ECT)
SENSOR.**
C
O
D
E
KEY ON. USING A
VOLTMETER, MEASURE
THE VOLTAGE OF THE
ECT SIGNAL CIRCUIT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 5.0 VOLTS?
YES
REPAIR ECT SIGNAL
CIRCUIT FOR A
SHORT TO B+
VOLTAGE. IF OK,
REPLACE PCM.*
NO
CONNECT A JUMPER
BETWEEN THE ECT
SENSOR SIGNAL AND
SENSOR GROUND CKT.
FIG. 1 OR 2
USING THE DRB,
READ THE ECT
SENSOR VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLT?
YES
REPLACE THE ENGINE
COOLANT
TEMPERATURE
SENSOR.*
NO
MOVE THE JUMPER
WIRE FROM THE
SENSOR GROUND TO
AN ENGINE GROUND.
FIG. 1 OR 2
USING THE DRB,
READ THE ECT
SENSOR VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLTS?
YES
REPAIR THE OPEN
SENSOR GROUND
CIRCUIT.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE THE
RESISTANCE OF THE
ECT SENSOR SIGNAL
CIRCUIT...
FIG. 3 OR 4
USE AN OHMMETER IN
THE FOLLOWING
STEP.
BETWEEN THE PCM
AND THE ECT
SENSOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE ECT
SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
123
T
E
S
T
S
T TEST TC-35A REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
124
TEST TC-35A
T
R
O
U
B
L
E
REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
Perform TEST DTC Before Proceeding
START TEST
TC-35A.
WARNING: BE SURE
TO KEEP HANDS AND
FEET CLEAR OF
ROTATING WHEELS.
RAISE THE DRIVE
WHEELS OFF THE
GROUND.
C
O
D
E
PUT TRANSMISSION
IN ANY FORWARD
GEAR. ALLOW THE
WHEELS TO ROTATE.
START THE ENGINE.
WITH THE DRB, READ
THE VEHICLE SPEED
SENSOR.
DOES THE DRB
DISPLAY ABOVE ZERO
MPH?
NO
CONTINUED TEST
TC-35A ON THE
NEXT PAGE.
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
125
T
E
S
T
S
T TEST TC-35A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
C
O
D
E
T
E
S
T
S
FIG. 1
126
TEST TC-35A
CONTINUED - REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
TEST TC-35A
CONTINUED FROM
PREVIOUS PAGE.
WITH THE WHEELS
STILL ROLLING,
OBSERVE THE
SPEEDOMETER.
DOES THE
SPEEDOMETER READ
ABOVE ZERO MPH?
YES
PERFORM TEST
TC-35C.
C
O
D
E
NO
HOIST VEHICLE, CHECK
THE VSS ADAPTER FOR
PROPER SEATING AND
POSITIONING. REFER
TO SERVICE MANUAL.
WAS THE ADAPTER
POSITIONED AND
SEATED PROPERLY.
NO
REPAIR AS
NECESSARY.*
YES
KEY OFF.
DISCONNECT THE
VEHICLE SPEED
SENSOR (VSS)
CONNECTOR.**
KEY ON. MEASURE
THE VOLTAGE AT THE
5-VOLT SUPPLY
CIRCUIT.
FIG. 1
IS THE VOLTAGE
ABOVE 4.0 VOLTS?
NO
REPAIR THE OPEN
5-VOLT SUPPLY
CIRCUIT.*
NO
CONTINUE TEST
TC-35A ON THE
NEXT PAGE.
NO
CONTINUE TEST
TC-35B ON THE
NEXT PAGE.
YES
KEY ON. MEASURE THE
VOLTAGE AT THE
VEHICLE SPEED SENSOR
SIGNAL CIRCUIT.
FIG. 1
IS THE VOLTAGE
ABOVE 4.5 VOLTS?
YES
USING A JUMPER WIRE,
CONNECT ONE END TO
THE VSS SENSOR
SIGNAL CIRCUIT.
FIG. 1
USING THE DRB,
OBSERVE THE VSS
SIGNAL DISPLAY....
WHILE TAPPING THE
OTHER END OF THE
JUMPER WIRE TO THE
SENSOR GROUND
CIRCUIT.
DOES THE DRB
DISPLAY VSS SIGNAL
MORE THAN 0 MPH?
YES
REMOVE THE VEHICLE
SPEED SENSOR.
INSPECT THE
SPEEDOMETER PINION
GEAR.
IS THE PINION GEAR
OK?
NO
REPAIR AS
NECESSARY.*
YES
REPLACE THE
VEHICLE SPEED
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
127
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-35A
R
O
U
TJ/XJ BODY
B
L
E
CONTINUED - REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
128
TEST TC-35A
CONTINUED - REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
TEST TC-35A
CONTINUED FROM
THE PREVIOS
PAGE.
MEASURE THE
RESISTANCE OF THE
VEHICLE SPEED
SENSOR SIGNAL
CIRCUIT...
KEY ON. DISCONNECT
THE POWERTRAIN
CONTROL MODULE.**
C
O
D
E
FROM THE PCM
CONNECTOR AND THE
VSS CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
SPEED SENSOR
SIGNAL CIRCUIT.*
FIG. 2
YES
MEASURE THE
RESISTANCE BETWEEN
THE VSS SIGNAL
CIRCUIT AND GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SPEED
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
129
T
E
S
T
S
T TEST TC-35B REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
R
O Perform TEST TC-35A Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
130
TEST TC-35B
T
R
O
U
B
L
E
REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
Perform TEST TC-35A Before Proceeding
START TEST
TC-35B.
CONNECT ONE END OF
A JUMPER WIRE TO
THE VSS SENSOR
SIGNAL CIRCUIT.
FIG. 1
USING THE DRB,
READ THE VSS
SIGNAL.
C
O
D
E
WHILE OBSERING THE
DRB DISPLAY, TAP
THE OTHER END OF
THE JUMPER TO A
WELL KNOWN GROUND.
DOES THE DRB
DISPLAY THE VSS
ABOVE 0 MPH?
YES
REPAIR THE SENSOR
GROUND CIRCUIT FOR
AN OPEN.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
131
T
E
S
T
S
T TEST TC-35C REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
R
O Perform TEST TC-35A Before Proceeding
TJ/XJ BODY
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
132
TEST TC-35C
T
R
O
U
B
L
E
REPAIRING - NO VEHICLE SPEED SENSOR SIGNAL
Perform TEST TC-35A Before Proceeding
START TEST
TC-35C
KEY ON. DISCONNECT
THE PCM
CONNECTORS.**
DISCONNECT THE VSS
HARNESS CONNECTOR.
C
O
D
E
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE OF THE
VSS SIGNAL CIRCUIT
BETWEEN THE PCM AND
THE VSS. FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.
NO
REPAIR THE VSS
SIGNAL CIRCUIT FOR
AN OPEN.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
133
T
E
S
T
S
T TEST TC-36A REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO MAP SENSOR
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
134
TEST TC-36A
REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO MAP SENSOR
Perform TEST DTC Before Proceeding
START TEST
TC-36A.
START ENGINE AND
LET IDLE.
T
R
O
U
B
L
E
C
O
D
E
WITH THE DRB, READ
THE MAP SENSOR
VOLTAGE.
IS THE MAP SENSOR
VOLTAGE BELOW 0.2
VOLTS?
YES
CONTINUE TEST
TC-36A ON THE
NEXT PAGE.
YES
CONTINUE TEST
TC-36A ON THE
NEXT PAGE.
NO
TURN IGNITION ON.
(ENGINE OFF)
WITH THE DRB, READ
THE MAP SENSOR
VOLTAGE.
IS TNE MAP SENSOR
VOLTAGE BELOW 2.35
VOLTS?
NO
WIGGLE MAP SENSOR
CONNECTOR AND
HARNESS.
MONITOR THE DRB
DISPLAY.
WAS THERE ANY MAP
SENSOR VOLTAGE
CHANGE?
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1 OR 2
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
NO
REFER TO GEN INFO
3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
135
T
E
S
T
S
T TEST TC-36A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO MAP
SENSOR
C
O
D
E
T
E
S
T
S
FIG. 1
136
TEST TC-36A
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO MAP
SENSOR
TEST TC-36A
CONTINUED FROM
THE PREVIOUS
PAGE.
TURN ENGINE OFF
AND IGNITION ON IF
ENGINE IS RUNNING.
DISCONNECT THE MAP
SENSOR HARNESS
CONNECTOR.**
T
R
O
U
B
L
E
C
O
D
E
USING A VOLTMETER,
MEASURE THE VOLTAGE
OF THE MAP SENSOR
5-VOLT SUPPLY
CIRCUIT AT THE...
MAP SENSOR
CONNECTOR.
IS THE VOLTAGE
ABOVE 4.5 VOLTS?
NO
CONTINUE TEST
TC-36A ON THE
NEXT PAGE.
FIG. 1
YES
USE THE DRB TO
READ THE MAP
SENSOR VOLTAGE.
IS THE MAP SENSOR
VOLTAGE ABOVE 4.5
VOLTS?
YES
REPLACE THE MAP
SENSOR.*
NO
TURN IGNITION OFF.
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE BETWEEN
THE MAP SENSOR
SIGNAL CIRCUIT
AND...
THE MAP SENSOR
GROUND CIRCUIT AT
MAP SENSOR
CONNECTOR.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE MAP
SENSOR SIGNAL
CIRCUIT SHORTED TO
MAP SENSOR GROUND
CIRCUIT.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
MAP SENSOR SIGNAL
CIRCUIT...
AT MAP SENSOR
CONNECTOR TO
GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE MAP
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
FIG. 1
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
137
T
E
S
T
S
T TEST TC-36A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO MAP
SENSOR
C
O
D
E
T
E
S
T
S
FIG. 1
138
TEST TC-36A
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO LOW/NO 5 VOLTS TO MAP
SENSOR
TEST TC-36A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
MEASURE THE
RESISTANCE OF THE
MAP SENSOR 5-VOLT
SUPPLY CIRCUIT...
TURN IGNITION OFF.
C
O
D
E
T
E
S
T
S
USE AN OHMMETER IN
THE FOLLOWING
STEP.
FROM THE MAP SENSOR
CONNECTOR TO THE PCM
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
5-VOLT SUPPLY
CIRCUIT.*
FIG. 1
YES
WITH AN
OHMMETER...
T
R
O
U
B
L
E
MEASURE THE MAP
SENSOR 5-VOLT SUPPLY
CKT FOR RESISTANCE
TO GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE 5-VOLT
SUPPLY CIRCUIT FOR
A SHORT TO
GROUND.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
139
T TEST TC-37A REPAIRING - MAP SENSOR VOLTAGE TOO HIGH
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
140
TEST TC-37A
T
R
O
U
B
L
E
REPAIRING - MAP SENSOR VOLTAGE TOO HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-37A.
START THE ENGINE.
C
O
D
E
USING THE DRB,
READ THE MAP
SENSOR VOLTAGE.
IS THE MAP SENSOR
VOLTAGE ABOVE 4.6
VOLTS?
YES
CONTINUE TEST
TC-37A ON THE
NEXT PAGE.
NO
WIGGLE MAP SENSOR
CONNECTOR &
HARNESS.
OBSERVE THE DRB
DISPLAY.
WAS THE VOLTAGE
ABOVE 4.6 VOLTS
WHEN WIGGLED?
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
HARNESS AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
141
T
E
S
T
S
T TEST TC-37A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
142
TEST TC-37A
T
R
O
U
B
L
E
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO HIGH
TEST TC-37A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY ON, ENGINE
OFF.
DISCONNECT THE MAP
SENSOR HARNESS
CONNECTOR.**
C
O
D
E
USING A VOLTMETER,
MEASURE THE
VOLTAGE OF THE MAP
SENSOR SIGNAL
CIRCUIT...
AT THE MAP SENSOR
HARNESS CONNECTOR.
IS THE VOLTAGE
ABOVE 5.0 VOLTS?
YES
FIG. 1
REPAIR MAP SENSOR
SIGNAL FOR A SHORT
TO VOLTAGE. IF
OKAY, REPLACE THE
PCM.*
NO
KEY OFF. USING AN
OHMMETER, MEASURE
THE RESISTANCE OF
THE MAP SENSOR
SIGNAL CIRCUIT...
TO THE 5 VOLT
SUPPLY CIRCUIT.
IS RESISTANCE
BELOW 5.0 OHMS.
YES
FIG. 1
REPAIR THE MAP
SENSOR SIGNAL
CIRCUIT FOR A SHORT
TO THE 5 VOLT SUPPLY
CIRCUIT.*
NO
CONNECT A JUMPER
WIRE BETWEEN THE
SENSOR SIGNAL AND
SENSOR GROUND CKTS.
FIG. 1
KEY ON. USING THE
DRB, READ THE MAP
SENSOR VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLTS?
YES
REPLACE THE MAP
SENSOR.*
NO
MOVE THE JUMPER WIRE
FROM THE SENSOR
GROUND CIRCUIT TO
ENGINE GROUND.
FIG. 1
READ THE MAP
SENSOR VOLTAGE.
IS THE MAP SENSOR
VOLTAGE BELOW 1.0
VOLTS?
YES
REPAIR THE MAP
SENSOR GROUND
CIRCUIT FOR AN
OPEN.*
NO
CONTINUE TEST
TC-37A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
143
T
E
S
T
S
T TEST TC-37A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
144
TEST TC-37A
CONTINUED - REPAIRING - MAP SENSOR VOLTAGE TOO HIGH
TEST TC-37A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
T
R
O
U
B
L
E
C
O
D
E
MEASURE THE
RESISTANCE OF THE
MAP SENSOR SIGNAL
CIRCUIT BETWEEN...
THE PCM AND THE
MAP SENSOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1
NO
REPAIR THE MAP
SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
145
T
E
S
T
S
T TEST TC-39A REPAIRING - NO CHANGE IN MAP FROM START TO RUN
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
146
TEST TC-39A
REPAIRING - NO CHANGE IN MAP FROM START TO RUN
Perform TEST DTC Before Proceeding
START TEST
TC-39A.
WITH THE DRB, READ
CODES. IS "MAP
SENSOR VOLTAGE TOO
LOW" CODE SET?
TURN IGNITION ON,
ENGINE OFF.
YES
PERFORM TEST
TC-36A.
C
O
D
E
NO
WITH THE DRB,
ERASE CODES, START
ENGINE, AND ALLOW
ENGINE TO IDLE FOR
30 SECONDS.
DOES THE DRB
DISPLAY "NO CHANGE
IN MAP FROM START
TO RUN"?
WITH THE DRB, READ
CODES.
YES
CONTINUE TEST
TC-39A ON NEXT
PAGE.
NO
NOTE: THE ENGINE
IS STILL RUNNING.
WITH THE DRB, SET
THE ENGINE SPEED
TO 1500 RPM.
WITH THE ENGINE
RPM AT 1500, READ
MAP SENSOR
VOLTAGE.
WHILE MONITORING
THE VOLTAGE,
WIGGLE THE WIRING
FROM THE MAP
SENSOR TO THE PCM.
DID THE ENGINE
STALL OR VOLTAGE
BECOME ERRATIC?
YES
REPAIR THE WIRING
OR CONNECTOR
DEFECT BETWEEN THE
MAP SENSOR AND THE
PCM.*
NO
STOP ACTUATION.
WHILE MONITORING
THE DRB DISPLAY,
SNAP THE THROTTLE
OPEN AND CLOSED.
DID THE VACUUM
DROP RAPIDLY BELOW
1.0"?
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.TEST
COMPLETE.*
FIG. 1
NO
REMOVE MAP SENSOR
AND INSPECT
CONDITON OF VACUUM
PORT.
ALSO INSPECT
CONDITION OF
INTAKE MANIFOLD OR
THROTTLE BODY
VACUUM PORT.
IS THERE A
RESTRICTION OR
DEFECT IN THE
VACUUM PORTS?
YES
REPAIR THE
RESTRICTED OR
DEFECTIVE VACUUM
PORTS.*
NO
REPLACE THE MAP
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
147
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-39A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - NO CHANGE IN MAP FROM START TO RUN
C
O
D
E
T
E
S
T
S
FIG. 1
148
TEST TC-39A
CONTINUED - REPAIRING - NO CHANGE IN MAP FROM START TO RUN
TEST TC-39A
CONTINUED FROM
PREVIOUS PAGE.
IGNITION KEY ON,
ENGINE OFF.
T
R
O
U
B
L
E
C
O
D
E
REMOVE MAP SENSOR
AND INSPECT
CONDITON OF VACUUM
PORT.
ALSO INSPECT
CONDITON OF INTAKE
MANIFOLD OR
THROTTLE BODY
VACUUM PORT.
WAS THERE A
RESTRICTION?
YES
REMOVE THE
RESTRICTION AND
REINSTALL THE MAP
SENSOR.*
NO
USE A VOLTMETER IN
THE FOLLOWING
STEP.
MEASURE THE MAP
SENSOR 5-VOLT
SUPPLY CIRCUIT.
IS THE VOLTAGE
ABOVE 4.5 VOLTS?
NO
REPAIR THE OPEN
MAP SENSOR 5-VOLT
SUPPLY CIRCUIT.*
FIG. 1
YES
REPLACE THE MAP
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
149
T
E
S
T
S
T TEST TC-40A REPAIRING - NO CRANK REFERENCE SIGNAL AT PCM
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
150
TEST TC-40A
T
R
O
U
B
L
E
REPAIRING - NO CRANK REFERENCE SIGNAL AT PCM
Perform TEST DTC Before Proceeding
START TEST
TC-40A.
KEY ON. USING THE
DRB, ERASE TROUBLE
CODES.
C
O
D
E
ATTEMPT TO START
THE ENGINE. IF IT
DOES NOT START,
CRANK FOR AT LEAST
15 SECONDS.
USING THE DRB,
READ ALL TROUBLE
CODES.
DID THE CODE "NO
CRANK SIGNAL AT
PCM" RETURN?
NO
PERFORM TEST
TC-40B.
YES
REPAIR AS
NECESSARY.*
YES
KEY OFF,
DISCONNECT THE
CRANKSHAFT
POSITION SENSOR
CONNECTOR.**
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT OR
MISWIRED?
NO
USING AN OHMMETER,
MEASURE THE CKP
SENSOR GROUND
CIRCUIT...
BETWEEN THE CKP
SENSOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE CKP
SENSOR GROUND
CIRCUIT TO THE
HARNESS SPLICE FOR
AN OPEN.*
YES
KEY ON. USING A
VOLTMETER, MEASURE
THE 5-VOLT SUPPLY
CIRCUIT...
AT THE CKP SENSOR
HARNESS CONNECTOR.
IS THE VOLTAGE
ABOVE 4.0 VOLTS?
NO
FIG. 1
REPAIR THE 5-VOLT
SUPPLY CIRCUIT FOR
AN OPEN.*
YES
CONNECT ONE END OF
A JUMPER WIRE TO
THE CKP SENSOR
SIGNAL CIRCUIT.
FIG. 1
USING THE DRB,
MONITOR CMP COUNT
WHILE TAPPING THE
END OF THE JUMPER
TO SENSOR GROUND.
DOES THE CURRENT
CKP COUNT CHANGE?
YES
REPLACE THE CKP
SENSOR.*
NO
CONTINUE TEST
TC-40A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
151
T
E
S
T
S
T TEST TC-40A
R
O
U
TJ/XJ BODY
B
L
E
CONTINUED - REPAIRING - NO CRANK REFERNCE SIGNAL AT PCM
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
152
TEST TC-40A
CONTINUED - REPAIRING - NO CRANK REFERNCE SIGNAL AT PCM
TEST TC-40A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
CKP SENSOR SIGNAL
CIRCUIT...
BETWEEN THE CKP
SENSOR CONNECTOR
AND THE PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE CKP
SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
FIG. 2
YES
MEASURE THE
RESISTANCE OF THE
CKP SENSOR SIGNAL
CIRCUIT...
BETWEEN THE CKP
SENSOR CONNECTOR AND
THE SENSOR GROUND .
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
FIG. 1
REPAIR THE CKP
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO THE
SENSOR GROUND.*
NO
MEASURE THE
RESISTANCE OF THE
CKP SENSOR SIGNAL
CIRCUIT...
BETWEEN THE CKP
SENSOR CONNECTOR
AND GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE CKP
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
FIG. 1
NO
MEASURE THE
RESISTANCE BETWEEN
THE CKP SENSOR
SIGNAL CIRCUIT AND
THE...
5-VOLT SUPPLY
CIRCUIT AT THE CKP
SENSOR CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
FIG. 1
YES
REPAIR THE CKP
SENSOR SIGNAL
CIRCUIT FOR A SHORT
TO THE 5-VOLT SUPPLY
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
153
T TEST TC-40B REPAIRING - NO CRANK REFERENCE SIGNAL AT PCM
R
O Perform TEST TC-40A Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
TJ/XJ BODY
FIG. 1
154
TEST TC-40B
REPAIRING - NO CRANK REFERENCE SIGNAL AT PCM
Perform TEST TC-40A Before Proceeding
START TEST
TC-40B.
ATTEMPT TO START
THE ENGINE IF NOT
ALREADY RUNNING.
DOES THE ENGINE
START?
NO
PERFORM NO
START TEST
NS-SEL.
C
O
D
E
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GEN INFO
3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
155
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-43A REPAIRING - IGNITION COIL #1 PRIMARY CIRCUIT
R
O Perform TEST DTC Before Proceeding
U TJ BODY
XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
156
TEST TC-43A
T
R
O
U
B
L
E
REPAIRING - IGNITION COIL #1 PRIMARY CIRCUIT
Perform TEST DTC Before Proceeding
START TEST
TC-43A
KEY OFF.
DISCONNECT THE
COIL WIRE AT THE
DISTRIBUTOR.
C
O
D
E
CONNECT THE CABLE
TO A SPARK TESTER.
T
E
S
T
S
CONNECT SPARK
TESTER TO GROUND.
FIG. 1
KEY ON, ENGINE
OFF.
USING THE DRB,
ACTUATE IGNITION
COIL.
IS THERE STRONG,
STEADY SPARK?
NO
CONTINUE TEST
TC-43A ON THE
NEXT PAGE.
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 2
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
WIGGLE WIRING
HARNESS FROM THE
IGNITION COIL TO
THE POWERTRAIN
CONTROL MODULE.
DOES THE SPARK
BECOME ERRATIC OR
STOP?
YES
REPAIR AS
NECESSARY WHERE
WIGGLING CAUSED
PROBLEM TO
APPEAR.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
INFORMATION ON
INTERMITTENT
TROUBLE CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
157
T TEST TC-43A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - IGNITION COIL #1 PRIMARY CIRCUIT
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
FIG. 5
158
TEST TC-43A
CONTINUED - REPAIRING - IGNITION COIL #1 PRIMARY CIRCUIT
TEST TC-43A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE
IGNITION COIL
CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
NO
KEY ON. USING THE
DRB, ACTUATE
IGNITION COIL.
USING A TEST LIGHT,
PROBE THE ASD RELAY
OUTPUT CIRCUIT.
DOES THE TEST
LIGHT ILLUMINATE
BRIGHTLY?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
FIG. 1 OR 2
YES
KEY OFF.
DISCONNECT PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE IGNITION
COIL DRIVER CIRCUIT
TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
IGNITION COIL
DRIVER CIRCUIT FOR
A SHORT TO
GROUND.*
NO
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE OF THE
IGNITION COIL
DRIVER CIRCUIT
BETWEEN THE PCM...
AND THE IGNITION
COIL.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
IGNITION COIL
DRIVER CIRCUIT FOR
AN OPEN.*
FIG. 3 OR 4
YES
USING AN OHMMETER,
MEASURE BETWEEN
THE IGNITION COIL
DRIVER CIRCUIT
AND...
THE ASD RELAY
OUTPUT CIRCUIT AT
THE IGNITION COIL
CONNECTOR.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
IGNITION COIL
DRIVER SHORTED TO
THE ASD RELAY
OUTPUT CIRCUIT.*
NO
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE ACROSS THE
IGNITION COIL
PRIMARY CIRCUIT.
IS THE RESISTANCE
BELOW 2.0 OHMS?
NO
REPLACE THE
IGNITION COIL.*
FIG. 5
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
159
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-44A REPAIRING - NO ASD RELAY OUTPUT VOLTAGE AT PCM
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
160
TEST TC-44A
REPAIRING - NO ASD RELAY OUTPUT VOLTAGE AT PCM
Perform TEST DTC Before Proceeding
IS A TROUBLE CODE
ALSO SET FOR "AUTO
SHUTDOWN RELAY
CONTROL CIRCUIT"?
START TEST
TC-44A.
YES
PERFORM TEST
TC-10A.
C
O
D
E
NO
DOES THE ENGINE
START?
NO
CONTINUE TEST
TC-44A ON THE
NEXT PAGE.
YES
THE CONDITION
REQUIRED TO SET
THE TROUBLE CODE
IS NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
ERASE FAULT CODES.
START ENGINE AND
LET IDLE.
WIGGLE WIRING
HARNESS FROM ASD
RELAY TO THE PCM.
RE-CHECK FAULT
CODES.
DID WIGGLING CAUSE
THE FAULT CODE TO
APPEAR?
YES
REPAIR AS NECESSARY
WHERE WIGGLING
CAUSED THE VOLTAGE
TO VARY.*
NO
TEST COMPLETE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
161
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-44A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - NO ASD RELAY OUTPUT VOLTAGE AT PCM
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
162
TEST TC-44A
CONTINUED - REPAIRING - NO ASD RELAY OUTPUT VOLTAGE AT PCM
TEST TC-44A
CONTINUED FROM
THE PREVIOUS
PAGE.
T
R
O
U
B
L
E
C
O
D
E
DISCONNECT THE
AUTO SHUTDOWN
(ASD) RELAY.**
USING A VOLTMETER,
MEASURE THE FUSED
B(+) CIRCUIT.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUSED
B(+) CIRCUIT FOR
AN OPEN.*
YES
REPLACE THE
ORIGINAL AUTO
SHUTDOWN RELAY.*
FIG. 1 OR 2
YES
INSTALL A
SUBSTITUTE RELAY
FOR THE ASD RELAY.
ATTEMPT TO START
THE VEHICLE.
DID THE ENGINE
START?
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
ASD RELAY OUTPUT
CIRCUIT...
BETWEEN THE RELAY
AND THE PCM.
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
FIG. 1 OR 2
NO
MEASURE THE ASD
RELAY OUTPUT
CIRCUIT FROM THE
RELAY CONNECTOR...
TO GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1 OR 2
YES
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR A
SHORT TO GROUND.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
163
T
E
S
T
S
T TEST TC-49A REPAIRING - PCM FAILURE EEPROM WRITE DENIED
R
O Perform TEST DTC Before Proceeding
U
NOTES
B
L
E
C
O
D
E
T
E
S
T
S
164
TEST TC-49A
REPAIRING - PCM FAILURE EEPROM WRITE DENIED
Perform TEST DTC Before Proceeding
START TEST
TC-49A.
USING THE DRB,
PERFORM THE SRI
MEMORY TEST.
DOES THE DRB
DISPLAY "WRITE
REFUSED"?
NO
TEST COMPLETE.*
C
O
D
E
YES
USING THE DRB,
PERFORM THE SRI
MEMORY TEST A
SECOND TIME.
DOES THE DRB
DISPLAY "WRITE
REFUSED" AGAIN?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
TEST COMPLETE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
165
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-57A REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE LOW
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
166
TEST TC-57A
REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE LOW
Perform TEST DTC Before Proceeding
START TEST
TC-57A.
USING THE DRB,
READ THE INTAKE
AIR TEMPERATURE
SENSOR VOLTAGE.
IS THE INTAKE AIR
TEMPERATURE SENSOR
VOLTAGE BELOW 0.5
VOLT?
YES
CONTINUE TEST
TC-57A ON THE
NEXT PAGE.
C
O
D
E
NO
WIGGLE THE INTAKE
AIR TEMP SENSOR
CONNECTOR &
HARNESS.
WAS THERE ANY
INTAKE AIR
TEMPERATURE SENSOR
VOLTAGE CHANGE?
MONITOR THE DRB
DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDTIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
167
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-57A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE LOW
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
168
TEST TC-57A
CONTINUED - REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE LOW
TEST TC-57A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
INTAKE AIR
TEMPERATURE (IAT)
SENSOR.**
C
O
D
E
IS THE INTAKE AIR
TEMPERATURE SENSOR
VOLTAGE ABOVE 4.0
VOLTS?
USING THE DRB,
READ THE IAT
SENSOR VOLTAGE.
YES
REPLACE THE INTAKE
AIR TEMPERATURE
SENSOR.*
NO
KEY OFF.
DISCONNECT THE PCM
HANRESS
CONNECTORS.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE BETWEEN
THE SENSOR SIGNAL
AND SENSOR GND CKT.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO SENSOR
THE GROUND
CIRCUIT.*
NO
USING AN OHMMETER
MEASURE THE
RESISTANCE OF...
IAT SENSOR SIGNAL
CIRCUIT TO GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO
GROUND.*
FIG. 1 OR 2
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
169
T
E
S
T
S
T TEST TC-58A REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE HIGH
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
170
TEST TC-58A
REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-58A.
KEY ON. USING THE
DRB, READ THE
INTAKE AIR
TEMPERATURE SENSOR
VOLTAGE.
IS THE INTAKE AIR
TEMPERATURE SENSOR
VOLTAGE ABOVE 4.5
VOLTS?
YES
CONTINUE TEST
TC-58A ON THE
NEXT PAGE.
C
O
D
E
NO
WIGGLE THE INTAKE
AIR TEMP SENSOR
CONNECTOR &
HARNESS.
WAS THERE ANY
INTAKE AIR
TEMPERATURE SENSOR
VOLTAGE CHANGE?
MONITOR DRB
DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
171
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-58A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE HIGH
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
172
TEST TC-58A
CONTINUED - REPAIRING - INTAKE AIR TEMP SENSOR VOLTAGE HIGH
TEST TC-58A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
INTAKE AIR
TEMPERATURE (IAT)
SENSOR.**
T
R
O
U
B
L
E
C
O
D
E
USING A VOLTMETER,
MEASURE THE
VOLTAGE OF THE IAT
SIGNAL CIRCUIT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 6.0 VOLTS?
YES
REPAIR IAT SIGNAL
CIRCUIT FOR A
SHORT TO VOLTAGE.*
YES
REPLACE THE INTAKE
AIR TEMPERATURE
SENSOR.*
NO
CONNECT A JUMPER
WIRE ACROSS THE IAT
SIGNAL AND SENSOR
GROUND CIRCUITS.
FIG. 1 OR 2
USING THE DRB,
READ THE INTAKE
AIR TEMPERATURE
SENSOR VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLTS?
NO
MOVE THE JUMPER
WIRE FROM THE
SENSOR GROUND TO
AN ENGINE GROUND.
FIG. 1 OR 2
READ THE INTAKE
AIR TEMPERATURE
SENSOR VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLTS?
YES
REPAIR THE OPEN
SENSOR GROUND
CIRCUIT.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
IAT SENSOR
SIGNAL...
BETWEEN THE PCM
AND THE IAT
SENSOR.
IS THE RESISTANCE
BELOW 5.O OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 3 OR 4
NO
REPAIR THE INTAKE
AIR TEMPERATURE
SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
173
T
E
S
T
S
T TEST TC-61A REPAIRING - INJECTOR #4 CONTROL CIRCUIT
R
O Perform TEST TC-21A Before Proceeding
U 2.5L
4.0L
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
2.5L
4.0L
FIG. 3
FIG. 4
174
TEST TC-61A
T
R
O
U
B
L
E
REPAIRING - INJECTOR #4 CONTROL CIRCUIT
Perform TEST TC-21A Before Proceeding
START TEST
TC-61A
KEY OFF.
DISCONNECT THE
INJECTOR #4
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE RESISTANCE
OF INJECTOR #4.
IS THE RESISTANCE
BETWEEN 10.0 AND
16.0 OHMS?
NO
REPLACE THE FUEL
INJECTOR.*
YES
KEY ON. USING THE
DRB, ACTUATE THE
AUTO SHUTDOWN
RELAY.
USING A TEST LIGHT
CONNECTED TO GROUND,
PROBE THE ASD RELAY
OUTPUT CIRCUIT.
FIG. 1 OR 2
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
WITH THE ASD RELAY
STILL ACTUATED,
USING A VOLTMETER,
MEASURE THE INJECTOR
DRIVER CIRCUIT...
BETWEEN THE
INJECTOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 1.0 VOLTS?
YES
REPAIR THE INJECTOR
#4 DRIVER CIRCUIT
FOR A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
INJECTOR #4 DRIVER
CIRCUIT TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
INJECTOR #4 DRIVER
CIRCUIT FOR A
SHORT TO GROUND.*
NO
WITH AN OHMMETER,
MEASURE ACROSS THE
INJECTOR #4 DRIVER
CIRCUIT.
FIG. 3 OR 4
FROM THE
POWERTRAIN CONTROL
MODULE TO THE
INJECTOR
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
INJECTOR #4 DRIVER
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
175
T
E
S
T
S
T TEST TC-62A REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE
R
O Perform TEST DTC Before Proceeding
U TJ BODY
XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
176
TEST TC-62A
T
R
O
U
B
L
E
REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE
Perform TEST DTC Before Proceeding
START TEST
TC-62A.
START ENGINE, LET
IDLE FOR AT LEAST
5 MINUTES.
C
O
D
E
USING THE DRB,
READ THE 1/1 O2
SENSOR VOLTAGE.
IS THE 1/1 O2
SENSOR VOLTAGE
ABOVE 1.5 VOLTS?
YES
CONTINUE TEST
TC-62A ON THE
NEXT PAGE.
NO
WIGGLE THE 1/1 O2
SENSOR CONNECTOR
AND HARNESS.
DID THE 1/1 O2
SENSOR VOLTAGE GO
ABOVE 1.5 VOLTS AT
ANY TIME ?
WHILE WIGGLE THE
HARNESS, WATCH THE
DRB DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
HAS THE
INTERMITTENT SHORT
SHORT TO VOLTAGE.*
NO
AT THIS TIME, THE
CONDITIONS
REQUIRED TO SET
THE CODE ARE NOT
PRESENT. FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING.
WERE THERE ANY
PROBLEMS FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFOMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
177
T
E
S
T
S
T TEST TC-62A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
178
TEST TC-62A
CONTINUED - REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE
TEST TC-62A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY ON. MEASURE
THE 1/1 O2 SENSOR
SIGNAL CIRCUIT...
KEY OFF.
DISCONNECT THE 1/1
O2 SENSOR HARNESS
CONNECTOR.**
USE A VOLTMETER IN
THE FOLLOWING
STEP.
BETWEEN THE 1/1 O2
SENSOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1 OR 2
WAS THE VOLTAGE
BETWEEN 4.2 AND
5.2 VOLTS?
C
O
D
E
NO
CONTINUE TEST
TC-62A ON THE
NEXT PAGE.
YES
INSTALL A JUMPER
WIRE FROM THE 1/1
O2 SENSOR SIGNAL
CIRCUIT TO THE
SENSOR GROUND...
AT THE 1/1 O2 SENSOR
HARNESS CONNECTOR.
OBSERVE THE DRB.
DID THE 1/1 O2
SENSOR VOLTAGE
DROP BELOW 1.0
VOLTS?
YES
REPLACE THE 1/1 O2
SENSOR.*
YES
REPAIR THE SENSOR
GROUND CIRCUIT FOR
AN OPEN.*
FIG. 1 OR 2
NO
MOVE THE JUMPER
WIRE FROM THE
SENSOR GROUND...
DID THE 1/1 O2
SENSOR VOLTAGE
DROP BELOW 1.0
VOLTS?
TO AN ENGINE
GROUND. OBSERVE
THE DRB.
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
179
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-62A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
180
TEST TC-62A
CONTINUED - REPAIRING - 1/1 O2 SENSOR SHORTED TO VOLTAGE
TEST TC-62A
CONTINUED FROM
THE PREVIOUS
PAGE.
WAS THE VOLTAGE
ABOVE 5.2 VOLTS?
YES
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE
BLACK PCM HARNESS
CONNECTOR.**
MEASURE THE 1/1 O2
SENSOR CIRCUIT
FROM THE 1/1 O2
SENSOR HARNESS
CONNECTOR...
C
O
D
E
T
E
S
T
S
USE AN OHMMETER IN
THE FOLLOWING
STEP.
TO THE PCM HARNESS
CONNECTOR.
WAS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
AN OPEN.*
FIG. 1 OR 2
YES
REPLACE THE PCM.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
181
T TEST TC-69A REPAIRING - INJECTOR #5 CONTROL CIRCUIT
R
O Perform TEST TC-21A Before Proceeding
U
4.0L
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
4.0L
FIG. 2
182
TEST TC-69A
T
R
O
U
B
L
E
REPAIRING - INJECTOR #5 CONTROL CIRCUIT
Perform TEST TC-21A Before Proceeding
START TEST
TC-69A
KEY OFF.
DISCONNECT THE
INJECTOR #5
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE RESISTANCE
OF INJECTOR #5.
IS THE RESISTANCE
BETWEEN 10.0 AND
16.0 OHMS?
NO
REPLACE THE FUEL
INJECTOR.*
YES
KEY ON. USING THE
DRB, ACTUATE AUTO
SHUTDOWN RELAY.
USING A TEST
LIGHT, PROBE THE
ASD RELAY OUTPUT
CIRCUIT.
FIG. 1
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
WITH THE ASD RELAY
STILL ACTUATING.
USING A VOLTMETER,
MEASURE THE INJECTOR
DRIVER CIRCUIT...
BETWEEN THE
INJECTOR HARNESS
CONNECTOR AND
GROUND.
FIG.1
IS THE VOLTAGE
ABOVE 1.0 VOLTS?
YES
REPAIR THE INJECTOR
#5 DRIVER CIRCUIT
FOR A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
INJECTOR #5 DRIVER
CIRCUIT TO GROUND.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
INJECTOR #5 DRIVER
CIRCUIT FOR A
SHORT TO GROUND.*
NO
USING AN OHMMETER,
MEASURE ACROSS THE
INJECTOR #5 DRIVER
CIRCUIT.
FIG. 2
BETWEEN THE
POWERTRAIN CONTROL
MODULE AND THE
INJECTOR
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
INJECTOR #5 DRIVER
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
183
T
E
S
T
S
T TEST TC-70A REPAIRING - INJECTOR #6 CONTROL CIRCUIT
R
O Perform TEST TC-21A Before Proceeding
U
4.0L
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
4.0L
FIG. 2
184
TEST TC-70A
T
R
O
U
B
L
E
REPAIRING - INJECTOR #6 CONTROL CIRCUIT
Perform TEST TC-21A Before Proceeding
START TEST
TC-70A
KEY OFF.
DISCONNECT THE
INJECTOR #6
CONNECTOR.**
C
O
D
E
USING AN OHMMETER,
MEASURE RESISTANCE
OF INJECTOR #6.
IS THE RESISTANCE
BETWEEN 10.0 AND
16.0 OHMS?
NO
REPLACE THE FUEL
INJECTOR.*
YES
KEY ON. USING THE
DRB, ACTUATE AUTO
SHUTDOWN RELAY.
USING A TEST
LIGHT, PROBE THE
ASD RELAY OUTPUT
CIRCUIT.
FIG. 1
DOES THE TEST
LIGHT ILLUMINATE?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
WITH THE ASD RELAY
STILL ACTUATING.
USING A VOLTMETER,
MEASURE THE INJECTOR
DRIVER CIRCUIT...
BETWEEN THE
INJECTOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1
IS THE VOLTAGE
ABOVE 1.0 VOLTS?
YES
REPAIR THE INJECTOR
#6 DRIVER CIRCUIT
FOR A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
INJECTOR #6 DRIVER
CIRCUIT TO GROUND.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
INJECTOR #6 DRIVER
CIRCUIT FOR A
SHORT TO GROUND.*
NO
USING AN OHMMETER,
MEASURE ACROSS THE
INJECTOR #6 DRIVER
CIRCUIT.
FIG. 2
BETWEEN THE
POWERTRAIN CONTROL
MODULE AND THE
INJECTOR
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE
INJECTOR #6 DRIVER
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
185
T
E
S
T
S
T TEST TC-82A REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL 12V DRIVER
CIRCUIT
R
Perform
TEST
DTC
Before Proceeding
O
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
XJ BODY
FIG. 2
FIG. 3
TJ BODY
XJ BODY
FIG. 4
FIG. 5
186
REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL 12V DRIVER
CIRCUIT
Perform TEST DTC Before Proceeding
TEST TC-82A
START TEST
TC-82A.
KEY ON, ENGINE
OFF. USING THE
DRB, ACTUATE THE
S/C POWER RELAY.
DISCONNECT THE
SPEED CONTROL
SERVO CONNECTOR.**
NOTE: ENSURE THE
BRAKE PEDAL IS NOT
DEPRESSED DURING THE
FOLLOWING STEPS.
USE A VOLTMETER IN
THE FOLLOWING
STEPS.
USING A VOLTMETER
MEASURE THE S/C
BRAKE SWITCH
OUTPUT CIRCUIT.
FIG. 1
DOES THE VOLTAGE
CYCLE FROM 0 TO 12
VOLTS?
YES
CONTINUE TEST
TC-82A ON THE
NEXT PAGE.
NO
KEY OFF. USING AN
OHMMETER, MEASURE
RESISTANCE OF THE
S/C BRAKE SWITCH
OUTPUT CIRCUIT...
BETWEEN THE SERVO
CONNECTOR AND
GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
FIG. 1
REPAIR THE
SWITCHED S/C BRAKE
SWITCH OUTPUT
CIRCUIT FOR A
SHORT TO GROUND.*
NO
DISCONNECT THE BRAKE
SWITCH CONN.** KEY
ON, ENGINE OFF.
ACTUATE S/C VENT
SOLENOID.
MEASURE VOLTAGE OF
THE 12V SUPPLY
CIRCUIT AT BRAKE
SWITCH CONN.
FIG. 2 OR 3
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
YES
PERFORM TEST
TC-82B.
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE RESISTANCE
OF 12V SUPPLY
CIRCUIT, PCM TO
BRAKE SWITCH CONN.
FIG. 4 OR 5
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE 12V
SUPPLY CIRCUIT FOR
AN OPEN.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
187
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-82A
R
O
U
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL
12V DRIVER CIRCUIT
C
O
D
E
T
E
S
T
S
TJ/XJ BODY
TJ/XJ BODY
FIG. 1
FIG. 2
188
TEST TC-82A
CONTINUED - REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL
12V DRIVER CIRCUIT
START TEST
TC-82A.
TURN IGNITION OFF.
T
R
O
U
B
L
E
C
O
D
E
USING AN OHMMETER,
MEASURE THE GROUND
CIRCUIT AT...
THE SERVO 4-WAY
HARNESS CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
SERVO GROUND
CIRCUIT.*
FIG. 1
YES
WITH AN OHMMETER,
PERFORM THE
FOLLOWING
MEASUREMENTS TO
GROUND..
SPEED CONTROL VENT
SOL CKT AND SPEED
CONTROL VACUUM SOL
CKT.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS FOR
EITHER
MEASUREMENT?
YES
REPAIR THE
CIRCUIT(S) THAT
MEASURED BELOW 5.0
OHMS FOR A SHORT
TO GROUND.*
NO
RECONNECT THE S/C
SERVO HARNESS
CONNECTOR.
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
MEASURE BETWEEN PCM
HARNESS CONNECTOR
CAVITIES C11 AND C5.
IS THE RESISTANCE
BETWEEN
NO
CONTINUE TEST
TC-82A ON THE
NEXT PAGE.
NO
CONTINUE TEST
TC-82A ON THE
NEXT PAGE.
35.0 AND 55.0
OHMS?
FIG. 2
YES
MEASURE BETWEEN PCM
HARNESS CONNECTOR
CAVITIES C11 AND C4.
IS THE RESISTANCE
BETWEEN
FIG. 2
35.0 AND 55.0
OHMS?
YES
REPALCE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
189
T
E
S
T
S
T TEST TC-82A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL
12V DRIVER CIRCUIT
C
O
D
E
T
E
S
T
S
FIG. 1
190
TEST TC-82A
CONTINUED - REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL
12V DRIVER CIRCUIT
TEST TC-82A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING AN OHMMETER,
MEASURE THE S/C
VACUUM SOLENOID
CONTROL CIRCUIT...
DISCONNECT THE S/C
SERVO 4-WAY
CONNECTOR.**
C
O
D
E
BETWEEN THE S/C
SERVO AND PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
S/C VACUUM
SOLENOID CONTROL
CIRCUIT.*
FIG. 1
YES
USING AN OHMMETER,
MEASURE THE S/C
VENT SOLENOID
CONTROL CIRCUIT...
BETWEEN THE S/C
SERVO AND PCM.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REAPIR THE OPEN
S/C VENT SOLENOID
CONTROL CIRCUIT.*
FIG. 1
YES
REPALCE THE SPEED
CONTROL SERVO.*
*Perform Verification TEST VER-4A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
191
T
E
S
T
S
T TEST TC-82B REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL 12V DRIVER
CIRCUIT
R
Perform
TEST
TC-82A
Before Proceeding
O
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
192
REPAIRING - SPEED CONTROL POWER RELAY OR SPEED CONTROL 12V DRIVER
CIRCUIT
Perform TEST TC-82A Before Proceeding
TEST TC-82B
START TEST
TC-82B.
WITH AN OHMMETER,
MEASURE RESISTANCE
OF THE S/C BRAKE
SWITCH OUTPUT CKT
FROM THE BRAKE...
C
O
D
E
SWITCH CONNECTOR TO
S/C SERVO CONNECTOR.
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
FIG. 1 OR 2
REPAIR THE OPEN
S/C BRAKE SWITCH
OUTPUT CIRCUIT
FROM PCM TO S/C
SERVO.*
NO
USING SERVICE
MANUAL PROCEDURE,
CHECK BRAKE SWITCH
ADJUSTMENT.
WAS THE BRAKE
SWITCH ADJUSTMENT
OK?
NO
ADJUST THE BRAKE
SWITCH.*
YES
REPLACE THE BRAKE
SWITCH.*
*Perform Verification TEST VER-4A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
193
T
E
S
T
S
T TEST TC-86A REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
194
TEST TC-86A
T
R
O
U
B
L
E
REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-86A.
WITH THE DRB UNDER
I/O’S, READ THE
SPEED CONTROL
INPUTS.
C
O
D
E
MONITORING THE DRB,
PUSH THE SPEED
CONTROL ON/OFF
SWITCH SEVERAL
TIMES, LEAVE ON.
DID THE DRB
DISPLAY SPEED
CONTROL SWITCH OFF
AND ON?
YES
PERFORM TEST
TC-86B.
NO
DISCONNECT THE
SPEED CONTROL
ON/OFF SWITCH
2-WAY HARNESS
CONNECTOR ONLY.**
MEASURE THE S/C SW
SIGNAL CKT FOR
VOLTAGE AT THE
ON/OFF SWITCH 2-WAY
CONN.
FIG. 1
IS THE VOLTAGE
ABOVE 6.0 VOLTS?
YES
REPAIR THE S/C
SWITCH SIGNAL CKT
FOR A SHORT TO
VOLTAGE.*
NO
TURN THE IGNITION
KEY OFF.
WAIT ONE MINUTE.
USING AN OHMMETER,
MEASURE THE S/C
SWITCH GROUND CKT AT
THE ON/OFF SWITCH
2-WAY CONN.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
GROUND CKT TO
SPEED CONTROL
SWITCH.*
YES
DISCONNECT THE
PCM.** USE AN
OHMMETER IN ALL
THE FOLLOWING
STEPS.
MEASURE THE S/C
SWITCH SIGNAL CKT,
PCM TO SC ON/OFF
SWITCH CONNECTOR.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
CONTINUE TEST
TC-86A ON THE
NEXT PAGE.
YES
MEASURE THE
RESISTANCE ACROSS
THE S/C ON/OFF
SWITCH WITH SWITCH
PRESSED.
IS THE RESISTANCE
BELOW 1.0 OHM?
YES
REPLACE POWERTRAIN
CONTROL MODULE.*
NO
REPLACE THE ON/OFF
SWITCH.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
195
T
E
S
T
S
T TEST TC-86A
R
O
U
B
L
E
CONTINUED - REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
196
TEST TC-86A
CONTINUED - REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH
TEST TC-86A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
CLOCK SPRING
HARNESS
CONNECTOR.**
T
R
O
U
B
L
E
C
O
D
E
MEASURE RESISTANCE
OF S/C SWITCH SIGNAL
CIRCUIT FROM PCM TO
CLOCK SPRING CONN.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
S/C SWITCH SIGNAL
CIRCUIT PCM TO
CLOCK SPRING.*
YES
REPAIR THE OPEN
S/C SWITCH SIGNAL
CIRCUIT AT CLOCK
SPRING.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
197
T
E
S
T
S
T TEST TC-86B REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH
R
O Perform TEST TC-86A Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
198
TEST TC-86B
T
R
O
U
B
L
E
REPAIRING - SPEED CONTROL SWITCH ALWAYS HIGH
Perform TEST TC-86A Before Proceeding
START TEST
TC-86B
AT THIS TIME THE
CONDITION REQUIRED
TO SET THIS TROUBLE
CODE IS NOT PRESENT.
FIG. 1
C
O
D
E
WITH THE DRB, WATCH
SWITCH VOLTAGE WHILE
WIGGLING WIRING, PCM
TO SPEED CONTROL
ON/OFF SWITCH.
WAS VOLTAGE ABOVE
4.9 VOLTS AT ANY
TIME WHILE
WIGGLING?
YES
REPAIR THE WIRING
AT THE POINT WHERE
VOLTAGE FLUCTUATES
WHEN HARNESS IS
WIGGLED.*
NO
PROBLEM DOES NOT
EXIST AT THIS
TIME.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
199
T
E
S
T
S
T TEST TC-87A REPAIRING - SPEED CONTROL SWITCH ALWAYS LOW
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
TJ/XJ BODY
TJ/XJ BODY
FIG. 1
FIG. 2
200
TEST TC-87A
T
R
O
U
B
L
E
REPAIRING - SPEED CONTROL SWITCH ALWAYS LOW
Perform TEST DTC Before Proceeding
START TEST
TC-87A.
RECORD ALL DTC’S
AND FREEZE FRAME
DATA, NOW ERASE
CODES BEFORE
PROCEEDING.
C
O
D
E
USING THE DRB,
READ THE S/C
SWITCH VOLTS.
IS THE S/C SWITCH
VOLTAGE BELOW 1.0
VOLTS?
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE TROUBLE
CODE IS NOT
PRESENT.*
YES
DISCONNECT THE
ON/OFF SWITCH
HARNESS
CONNECTOR.**
DID THE S/C SWITCH
VOLTS CHANGE TO
5.0 VOLTS?
YES
REPLACE THE S/C
ON/OFF SWITCH.*
YES
REPLACE THE S/C
CANCEL SWITCH.*
YES
REPAIR S/C SIGNAL
CIRCUIT SHORTED TO
SENSOR GROUND.*
NO
DISCONNECT THE
RESUME/ACCEL/CANCEL
SWITCH HARNESS
CONNECTOR.**
DID THE S/C SWITCH
VOLTS CHANGE TO
5.0 VOLTS?
NO
KEY OFF. WAIT ONE
MINUTE. USING AN
OHMMETER, MEASURE
THE RESISTANCE
BETWEEN...
THE S/C SIGNAL
CIRCUIT AND THE
SENSOR GROUND
CIRCUIT.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE RESISTANCE
OF THE S/C SWITCH
SIGNAL CKT TO GND.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
YES
REPAIR S/C SWITCH
SIGNAL CIRCUIT FOR
A SHORT TO
GROUND.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
201
T
E
S
T
S
T TEST TC-101A REPAIRING - FUEL PUMP (SYSTEM) RELAY CONTROL CIRCUIT
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
202
TEST TC-101A
REPAIRING - FUEL PUMP (SYSTEM) RELAY CONTROL CIRCUIT
Perform TEST DTC Before Proceeding
START TEST
TC-101A.
KEY ON. USING THE
DRB, ACTUATE THE
FUEL PUMP RELAY.
IS THE FUEL PUMP
RELAY CLICKING?
NO
CONTINUE TEST
TC-101A ON THE
NEXT PAGE.
YES
THE CONDITION
REQUIRED TO SET
THE TROUBLE CODE
IS NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
USING THE DRB,
ACTUATE THE FUEL
PUMP RELAY.
WIGGLE THE WIRING
HARNESS FROM THE
RELAY TO THE
POWERTRAIN CONTROL
MODULE.
DID THE RELAY
CLICKING STOP OR
BECOME IRREGULAR
WHEN WIGGLING THE
WIRES?
YES
REPAIR CIRCUIT AS
NECESSARY WHERE
WIGGLING CAUSED THE
CLICKING TO STOP OR
BECOME IRREGULAR.
NO
TEST COMPLETE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
203
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-101A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - FUEL PUMP (SYSTEM) RELAY CONTROL CIRCUIT
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
TJ BODY
XJ BODY
FIG. 5
FIG. 6
204
TEST TC-101A
CONTINUED - REPAIRING - FUEL PUMP (SYSTEM) RELAY CONTROL CIRCUIT
TEST TC-101A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
FUEL PUMP RELAY.**
C
O
D
E
USING A VOLTMETER,
MEASURE THE FUSED
IGN SWITCH OUTPUT
CKT AT RELAY CONN.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUSED
IGN SWITCH OUTPUT
CIRCUIT FOR AN
OPEN.*
NO
REPLACE FUEL PUMP
RELAY.*
YES
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE BETWEEN
TERMINALS 85 AND 86
OF THE FUEL PUMP
RELAY. FIG. 3 OR 4
IS THE RESISTANCE
BETWEEN 70 TO 90
OHMS?
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE FUEL
PUMP RELAY CONTROL
CKT AT PCM TO GND.
FIG. 5 OR 6
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE FUEL
PUMP RELAY CONTROL
CIRCUIT FOR A
SHORT TO GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
FUEL PUMP RELAY
CONTROL CIRCUIT...
T
R
O
U
B
L
E
BETWEEN THE PCM AND
THE FUEL PUMP RELAY.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE FUEL
PUMP RELAY CONTROL
CIRCUIT FOR AN
OPEN.*
FIG. 5 OR 6
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
205
T
E
S
T
S
T TEST TC-114A REPAIRING - P/N SWITCH STUCK IN PARK OR GEAR
R
O Perform TEST DTC Before Proceeding
U XJ BODY (2.5L)
TJ BODY (2.5L AND 4.0L)
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY (4.0L)
FIG. 1
206
TEST TC-114A
T
R
O
U
B
L
E
REPAIRING - P/N SWITCH STUCK IN PARK OR GEAR
Perform TEST DTC Before Proceeding
START TEST
TC-114A.
KEY ON. USING THE
DRB, OBSERVE
PARK/NEUTRAL
SWITCH INPUT
STATE.
C
O
D
E
MOVE THE GEAR
SELECTOR FROM PARK
TO REVERSE WHILE
OBSERVING THE DRB
DISPLAY.
DID THE DRB
DISPLAY "P/N" AND
"D/R"?
NO
CONTINUE TEST
TC-114A ON THE
NEXT PAGE.
YES
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
INSPECT THE WIRING
AND CONNECTORS
RELATING TO PARK
NEUTRAL POSITION
SWITCH.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORAMTION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
207
T
E
S
T
S
T TEST TC-114A
R
O
U
ALL OTHERS
B
L
E
CONTINUED - REPAIRING - P/N SWITCH STUCK IN PARK OR IN GEAR
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY 4.0L
FIG. 2
208
TEST TC-114A
CONTINUED - REPAIRING - P/N SWITCH STUCK IN PARK OR IN GEAR
TEST TC-114A
CONTINUED FROM
PREVIOUS PAGE.
MOVE THE GEAR
SELECTOR TO THE
PARK POSITION. KEY
OFF.
T
R
O
U
B
L
E
C
O
D
E
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE BETWEEN
THE P/N SW SENSE
CIRCUIT AT THE PCM
AND GND. FIG. 1 OR 2
OBSERVE OHMMETER
DISPLAY WHILE MOVING
GEAR SELECTOR FROM
PARK TO REVERSE AND
BACK TO PARK.
T
E
S
T
S
DID THE RESISTANCE
CHANGE FROM BELOW
10.0 OHMS TO ABOVE
10.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
CONTINUE TEST
TC-114A ON THE
NEXT PAGE.
NO
WAS THE RESISTANCE
BELOW 10.0 OHMS AT
ALL TIMES?
YES
DISCONNECT THE P/N
POSITION SW
CONNECTOR (TRANS
RANGE SENSOR)
HARNESS CONN.
MEASURE THE
RESISTANCE BETWEEN
THE P/N SWITCH SENSE
CIRCUIT AND GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR P/N SWITCH
SENSE CKT FOR A
SHORT TO GROUND.*
NO
REPLACE
PARK/NEUTRAL
POSITION SW OR
(TRANSMISSION
RANGE SENSOR).*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
209
T TEST TC-114A
R
O
U
ALL OTHERS
B
L
E
CONTINUED - REPAIRING - P/N SWITCH STUCK IN PARK OR GEAR
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY 4.0L
FIG. 2
210
TEST TC-114A
CONTINUED - REPAIRING - P/N SWITCH STUCK IN PARK OR GEAR
TEST TC-114A
CONTINUED FROM
PREVIOUS PAGE.
DISCONNECT THE P/N
POSITION SW
CONNECTOR (TRANS
RANGE SENSOR).**
T
R
O
U
B
L
E
C
O
D
E
MEASURE THE
RESISTANCE OF THE
P/N SWITCH SENSE
CIRCUIT...
BETWEEN THE PCM
CONNECTOR AND THE
P/N SWITCH
CONNECTOR.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE OPEN
P/N SWITCH SENSE
CIRCUIT.*
NO
IS THIS VEHICLE
EQUIPPED WITH A
4-SPEED AISIN
TRANSMISSION?
NO
REPLACE THE
PARK/NEUTRAL
POSITION SWITCH OR
(TRANSMISSION
RANGE SENSOR).*
YES
USING AN OHMMETER,
MEASURE THE GROUND
CIRCUIT AT THE TRANS
RANGE HARNESS
CONNECTOR. FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE GROUND
CIRCUIT.*
YES
REPLACE THE
TRANSMISSION RANGE
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
211
T
E
S
T
S
T TEST TC-115A REPAIRING - POWER STEERING SWITCH FAILURE
R
O Perform TEST DTC Before Proceeding
U
2.5L TJ/XJ
B
L
E
C
O
D
E
T
E
S
T
S
212
TEST TC-115A
REPAIRING - POWER STEERING SWITCH FAILURE
Perform TEST DTC Before Proceeding
START TEST
TC-115A
START ENGINE. WITH
DRB, MONITOR THE
P/S SW. TURN THE
STEERING WHEEL TO
BOTH EXTREMES.
DID THE POWER
STEERING PRESSURE
SWITCH CHANGE
STATE?
NO
CONTINUE TEST
TC-115A ON THE
NEXT PAGE.
YES
USING THE
SCHEMATIC, INSPECT
THE WIRING AND
HARNESSES.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
WITH THE DRB
MONITOR THE P/S
SWITCH STATE,
WHILE WIGGLING THE
HARNESS.
DID THE POWER
STEERING SWITCH
CHANGE STATE?
YES
REPAIR THE HARNESS
AS NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
213
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-115A
R
O
U
2.5L TJ/XJ
B
L
E
CONTINUED - REPAIRING POWER STEERING SWITCH FAILURE
C
O
D
E
T
E
S
T
S
FIG. 1
2.5L TJ/XJ
FIG. 2
214
TEST TC-115A
CONTINUED - REPAIRING POWER STEERING SWITCH FAILURE
TEST TC-115A
CONTINUED FROM
THE PREVIOUS
PAGE.
ENGINE OFF, KEY
ON. DISCONNECT THE
POWER STEERING
PRESSURE SWITCH.**
CONNECT A JUMPER
WIRE TO THE POWER
STEERING PRESSURE
SWITCH CIRCUIT.
FIG. 1
T
R
O
U
B
L
E
C
O
D
E
WITH THE DRB,
MONITOR THE POWER
STEERING PRESSURE
SWITCH.
DID THE POWER
STEERING PRESSURE
SWITCH CHANGE
STATES?
TOUCH THE OTHER
END OF THE JUMPER
TO GROUND 5 TIMES.
YES
CONTINUE TEST
TC-115A ON THE
NEXT PAGE.
NO
DISCONNECT
POWERTRAIN CONTROL
MODULE.**
USING AN OHMMETER
MEASURE THE P/S
PRESSURE SW CKT
FROM THE PCM TO
THE CONN. FIG. 2
WAS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
POWER STEERING
PRESSURE SWITCH
CIRCUIT.*
YES
MEASURE THE P/S
PRESSURE SWITCH
CIRCUIT AT THE P/S
SWITCH TO GROUND.
FIG. 1
WAS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE POWER
STEERING PRESSURE
SWITCH CIRCUIT FOR
A SHORT TO
GROUND.*
NO
REPLACE POWERTRAIN
CONTROL MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
215
T
E
S
T
S
T TEST TC-115A
R
O
U
B
L
E
CONTINUED - REPAIRING - POWER STEERING SWITCH FAILURE
C
O
D
E
T
E
S
T
S
2.5L TJ/XJ
FIG. 1
216
TEST TC-115A
CONTINUED - REPAIRING - POWER STEERING SWITCH FAILURE
TEST TC-115A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING AN OHMMETER,
MEASURE THE GROUND
CKT AT PS PRESSURE
SWITCH CONNECTOR.
FIG. 1
IS RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR OPEN GROUND
CIRCUIT.*
C
O
D
E
YES
REPLACE POWER
STEERING PRESSURE
SWITCH.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
217
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-118A REPAIRING - FUEL SYSTEM RICH 1/1 RICH
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
218
TEST TC-118A
REPAIRING - FUEL SYSTEM RICH 1/1 RICH
Perform TEST DTC Before Proceeding
START TEST
TC-118A.
NOTE: REPAIR ALL
OTHER O2 SENSOR
RELATED TROUBLE
CODES AND T.S.B.’S
BEFORE PROCEEDING.
ARE THERE ANY
OTHER TROUBLE
CODES OR T.S.B.’S
THAT APPLY?
YES
PERFORM THE
DTC TEST OR
T.S.B.’S THAT
APPLY.
C
O
D
E
NO
NOTE:
REFER TO FIGURE 1
FOR POSSIBLE
TROUBLE CODE
CAUSES.
PERFORM O2 HEATER
TEST TC-103A.
DID TEST TC-103A
PASS?
NO
REPAIR AS
NECESSARY.*
NO
REPAIR AS
NECESSARY.*
YES
PERFORM
FUEL DELIVERY TEST
NTC-5A.
DID TEST NTC-5A
PASS?
YES
KEY ON, ENGINE
OFF. READ THE
1/1 O2 SENSOR LONG
TERM ADAPTIVE
MEMORY VALUE.
IS THE LONG TERM
ADAPTIVE MEMORY
BETWEEN
-18% TO -25%?
NO
THE CONDITION
REQUIRED TO SET THIS
TROUBLE CODE IS NO
LONGER PRESENT.
TEST COMPLETE.*
YES
PERFORM TEST
TC-118B.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
219
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-118B REPAIRING - FUEL SYSTEM RICH 1/1 RICH
R
O Perform TEST TC-118A Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
220
TEST TC-118B
REPAIRING - FUEL SYSTEM RICH 1/1 RICH
Perform TEST TC-118A Before Proceeding
Using the test schematic as a guide, make sure all the wiring and connectors are okay.
Perform each of the following tests in the order listed below. If a test passes, continue to the next
until the problem is found.
Fuel Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-5A
Coolant Temperature Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-6A
Throttle Position Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-7A
MAP Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-8A
Engine Mechanical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-13A
Evaporative Emission Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-17A
221
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-119A REPAIRING - FUEL SYSTEM LEAN 1/1 LEAN
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
222
TEST TC-119A
REPAIRING - FUEL SYSTEM LEAN 1/1 LEAN
Perform TEST DTC Before Proceeding
START TEST
TC-119A.
NOTE: VERY LOW FUEL
LEVEL COULD CAUSE
THIS TROUBLE CODE TO
SET. MAKE SURE TANK
IS AT LEAST 1/4 FULL
DID THE VEHICLE
RUN OUT OF FUEL
SHORTLY BEFORE
COMING IN?
YES
ERASE TROUBLE
CODES.
TEST COMPLETE.*
C
O
D
E
NO
REFER TO
FIGURE 1
FOR POSSIBLE
TROUBLE CODE
CAUSES.
ARE THERE ANY
OTHER TROUBLE
CODES OR T.S.B.’S
THAT APPLY?
WITH THE DRB, READ
ALL TROUBLE CODES.
YES
PERFORM THE
DTC TEST OR
THE T.S.B.’S
THAT APPLY.
NO
PERFORM
FUEL DELIVERY TEST
NTC-3A.
DID TEST NTC-3A
NO
REPAIR AS
NECESSARY.*
PASS?
YES
START THE ENGINE
AND ALLOW IT TO
REACH NORMAL
OPERATING
TEMPERATURE.
CHECK
SYSTEM
BETWEEN
THE O2
EXHAUST
FOR LEAKS
ENGINE AND
SENSORS.
ARE THERE ANY
EXHAUST LEAKS?
YES
REPAIR OR REPLACE
EXHAUST COMPONENTS
AS NECESSARY.*
NO
CYCLE KEY OFF,
THEN ON.
READ THE
1/1 O2 SENSOR LONG
TERM ADAPTIVE
MEMORY VALUES.
ARE ANY OF THE
LONG TERM ADAPTIVE
MEMORY BETWEEN
+20% AND +32%?
YES
THE CONDITION
REQUIRED TO SET THIS
TROUBLE CODE IS NO
LONGER PRESENT.
TEST COMPLETE.*
NO
PERFORM TEST
TC-119B.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
223
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-119B REPAIRING - FUEL SYSTEM LEAN 1/1 LEAN
R
O Perform TEST TC-119A Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
224
TEST TC-119B
REPAIRING - FUEL SYSTEM LEAN 1/1 LEAN
Perform TEST TC-119A Before Proceeding
Using the test schematic as a guide, make sure all the wiring and connectors are okay.
Perform each of the following tests in the order listed below. If a test passes, continue to the next
until the problem is found.
Fuel Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-5A
Coolant Temperature Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-6A
Throttle Position Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-7A
MAP Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-8A
Engine Mechanical Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .TEST NTC-13A
225
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-126A REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE
R
O Perform TEST DTC Before Proceeding
U TJ BODY
XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
226
TEST TC-126A
T
R
O
U
B
L
E
REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE
Perform TEST DTC Before Proceeding
START TEST
TC-126A.
START ENGINE, LET
IDLE FOR AT LEAST
5 MINUTES.
C
O
D
E
USING THE DRB,
READ THE 1/2 O2
SENSOR VOLTAGE.
IS THE 1/2 O2
SENSOR VOLTAGE
ABOVE 1.5 VOLTS?
YES
CONTINUE TEST
TC-126A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME, THE
CONDITIONS REQUIRED
TO SET THE CODE ARE
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING.
WERE THERE ANY
PROBLEMS FOUND?
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
227
T
E
S
T
S
T TEST TC-126A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
228
TEST TC-126A
CONTINUED - REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE
TEST TC-126A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE 1/2
O2 SENSOR HARNESS
CONNECTOR.**
USE A VOLTMETER IN
THE FOLLOWING
STEP.
T
R
O
U
B
L
E
C
O
D
E
KEY ON. MEASURE
THE 1/2 O2 SENSOR
SIGNAL CIRCUIT...
BETWEEN THE 1/2 O2
SENSOR HARNESS
CONNECTOR AND
GROUND.
FIG. 1 OR 2
WAS THE VOLTAGE
BETWEEN 4.0 AND
5.2 VOLTS?
NO
CONTINUE TEST
TC-126A ON THE
NEXT PAGE.
YES
INSTALL A JUMPER
WIRE FROM THE 1/2
O2 SENSOR SIGNAL
CIRCUIT TO THE
SNESOR GROUND...
AT THE 1/2 O2
SENSOR HARNESS
CONNECTOR. OBSERVE
THE DRB.
FIG. 1 OR 2
DID THE 1/2 O2
SENSOR VOLTAGE
DROP BELOW 1.0
VOLTS?
YES
REPLACE THE 1/2 O2
SENSOR.*
YES
REPAIR THE SENSOR
GROUND CIRCUIT FOR
AN OPEN.*
NO
MOVE THE JUMPER
WIRE FROM THE
SENSOR GROUND...
DID THE 1/2 O2
SENSOR VOLTAGE
DROP BELOW 1.0
VOLTS?
TO AN ENGINE
GROUND. OBSERVE
THE DRB.
NO
REPLACE THE PCM.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
229
T
E
S
T
S
T TEST TC-126A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
230
TEST TC-126A
CONTINUED - REPAIRING - 1/2 O2 SENSOR SHORTED TO VOLTAGE
TEST TC-126A
CONTINUED FROM
THE PREVIOUS
PAGE.
WAS THE VOLTAGE
ABOVE 5.2 VOLTS?
YES
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO
VOLTAGE. IF OKAY,
REPLACE PCM.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
MEASURE THE 1/2 O2
SENSOR CIRCUIT
FROM THE 1/2 O2
SENSOR HARNESS
CONNECTOR...
C
O
D
E
T
E
S
T
S
USE AN OHMMETER IN
THE FOLLOWING
STEP.
TO THE PCM HARNESS
CONNECTOR.
WAS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE SENSOR
SIGNAL CIRCUIT FOR
AN OPEN.*
FIG.1 OR 2
YES
REPLACE THE PCM.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
231
T TEST TC-132A REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
232
TEST TC-132A
REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP
Perform TEST DTC Before Proceeding
START TEST
TC-132A.
KEY ON, ENGINE
OFF.
USING THE DRB READ
TROUBLE CODES.
IS A MAP SENSOR
TROUBLE CODE
PRESENT?
YES
PERFORM "DTC
TEST".
C
O
D
E
NO
WITH THE DRB READ
THE MAP SENSOR
VOLTAGE.
IS MAP SENSOR
VOLTAGE BELOW 3.5
VOLTS?
YES
PERFORM TEST
NTC-6A.
NO
PERFORM TEST
NTC-6A.
NO
START ENGINE.
DID THE MAP SENSOR
VOLTAGE DROP FROM
ABOVE 3.5 VOLTS TO
BELOW 2.0 VOLTS?
WITH THE DRB READ
THE MAP SENSOR
VOLTAGE.
YES
NOTE: TO HAVE A
CLEAR
UNDERSTANDING OF
THIS TROUBLE CODE
READ. FIG. 1
*Perform Verification TEST VER-2A.
CONTINUE TEST
TC-132A ON THE
NEXT PAGE.
**Check connectors - Clean / repair as necessary.
233
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-132A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP
C
O
D
E
T
E
S
T
S
FIG. 1
234
TEST TC-132A
CONTINUED - REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP
TEST TC-132A
CONTINUED FROM
THE PREVIOUS
PAGE.
CHECK THROTTLE
PLATE AND LINKAGE
FOR A BINDING
CONDITION.
T
R
O
U
B
L
E
C
O
D
E
ENSURE THE
THROTTLE LINKAGE
IS AT THE IDLE
POSITION.
NOTE: TP SENSOR GND
CIRCUIT AND THE 5
VOLT SUPPLY CKT
SWITCHED WILL CAUSE
THIS CODE TO APPEAR.
T
E
S
T
S
DISCONNECT THE TP
SENSOR.**
INSPECT TP SENSOR
WIRE COLORS FOR
THE CORRECT
CAVITIES.**
FIG. 1
IS ANY TERMINAL
DAMAGED PUSHED OUT
OR CORRODED?
YES
CLEAN OR REPAIR
CONNECTOR AS
NECESSARY.*
NO
WITH A VOLTMETER
MEASURE THE 5 VOLT
SUPPLY CIRCUIT.
IS THE VOLTAGE
BELOW 5.0 VOLTS?
YES
REPAIR THE OPEN 5
VOLT SUPPLY
CIRCUIT TO TP
SENSOR.*
FIG. 1
NO
RECONNECT THROTTLE
POSITION SENSOR
CONNECTOR.
TURN IGNITION ON
(ENGINE OFF).
WITH THE DRB, READ
THE THROTTLE
POSITION SENSOR
VOLTAGE.
IS THE THROTTLE
POSITION SENSOR
VOLTAGE ABOVE 1.0
VOLTS?
YES
REPLACE THROTTLE
POSITION SENSOR.*
NO
CONTINUE TEST
TC-132A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
235
T TEST TC-132A
R
O
U
B
L
E
CONTINUED - REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP
C
O
D
E
T
E
S
T
S
236
TEST TC-132A
CONTINUED - REPAIRING - TPS VOLTAGE DOES NOT AGREE WITH MAP
TEST TC-132A
CONTINUED FROM
THE PREVIOUS
PAGE.
WHILE MONITORING
THE DRB, SLOWLY
OPEN AND CLOSE THE
THROTTLE PLATE.
T
R
O
U
B
L
E
C
O
D
E
NOTE: YOU MUST
MOVE LINKAGE VERY
SLOWLY WHILE
LOOKING FOR A JUMP
IN VOLTAGE.
IS THE VOLTAGE
CHANGE SMOOTH?
NO
REPLACE THROTTLE
POSITION SENSOR.*
NO
REPLACE THROTTLE
POSITION SENSOR.*
YES
REPAIR THE HARNESS
OR CONNECTORS AS
NECESSARY.*
YES
WHILE MONITORING
THE DRB, OPEN THE
THROTTLE PLATE TO
WIDE OPEN
THROTTLE.
IS THE THROTTLE
POSITION SENSOR
VOLTAGE ABOVE 3.5
VOLTS?
YES
USING THE SCHEMATIC
AS A GUIDE, WIGGLE
THE TP SENSOR
HARNESS AND
CONNECTORS TO PCM.
WHILE MONITORING
THE DRB, OBSERVE
FOR THE TP SENSOR
VOLTAGE TO CHANGE.
DID THE TP SENSOR
VOLTAGE CHANGE AT
ANY TIME?
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
237
T
E
S
T
S
T TEST TC-148A REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT LOCK-UP (TJ/XJ
BODY WITH 3 SPD AUTO TRANS)
R
Perform
TEST
DTC
Before Proceeding
O
U
TJ/XJ BODY WITH 3 SPD AUTO TRANSMISSION
B
L
E
C
O
D
E
T
E
S
T
S
TJ/XJ BODY WITH 3 SPD AUTO TRANSMISSION
238
REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT LOCK-UP (TJ/XJ
BODY WITH 3 SPD AUTO TRANS)
Perform TEST DTC Before Proceeding
TEST TC-148A
START TEST
TC-148A
IS THE THROTTLE
POSITION SENSOR
VOLTAGE TOO LOW
CODE SET?
USING THE DRB,
READ THE TROUBLE
CODES.
YES
PERFORM TEST
TC-26A.
C
O
D
E
NO
IS THE THROTTLE
POSITION SENSOR
VOLTAGE TOO HIGH
CODE SET?
YES
PERFORM TEST
TC-27A.
YES
PERFORM TEST
TC-49A.
YES
PERFORM TEST
TC-12A.
YES
PERFORM TEST
TC-40A.
NO
IS THE PCM FAILURE
EEPROM WRITE
DENIED CODE SET?
NO
IS THE TORQUE
CONVERTER CLUTCH
SOLENOID TROUBLE
CODE PRESENT?
NO
IS THE NO CRANK
REFERENCE SIGNAL
AT PCM TROUBLE
CODE PRESENT?
NO
CONTINUE TEST
TC-148A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
239
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-148A CONTINUED - REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT
LOCK-UP (TJ/XJ BODY WITH 3 SPD AUTO TRANS)
R
O
U
TJ/XJ BODY WITH 3 SPD AUTO TRANSMISSION
B
L
E
C
O
D
E
T
E
S
T
S
TJ/XJ BODY WITH 3 SPD AUTO TRANSMISSION
240
TEST TC-148A
CONTINUED - REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT
LOCK-UP (TJ/XJ BODY WITH 3 SPD AUTO TRANS)
START TEST
TC-148A.
CHECK TRANSMISSION
FLUID AND FOR ANY
DEBRIS.
IS THE FLUID LEVEL
OK AND CLEAR FROM
CONTAMINATION?
NO
REPAIR AS
NECESSARY.*
C
O
D
E
YES
ROAD TEST VEHICLE
WHILE MONITORING
TCC STATE AND
ENGINE RPM WITH
DRB.
DOES THE ENGINE
RPM DROP WHEN THE
TCC STATE GOES TO
ON?
YES
CONTINUE TEST
TC-148A ON THE
NEXT PAGE.
YES
REPAIR INTERNAL
TRANSMISSION
PROBLEM.*
NO
DOES THE PAN
CONTAIN EXCESSIVE
DEBRIS AND/OR IS
THE FLUID BURNT?
REMOVE OIL PAN AND
CHECK FOR DEBRIS
OR BURNT OIL.
NO
REPLACE TCC
SOLENOID.
ACCELERATE VEHICLE
TO 60 MPH
MAINTAINING A
CONSTANT 20 DEGREE
THROTTLE ANGLE.
ROAD TEST VEHICLE
WHILE MONITORING
THROTTLE ANGLE
USING THE DRB.
USING THE DRB,
CLEAR CODES.
REPEAT THE
ACCELRATION TEST 4
TIMES.
USING THE DRB,
READ DTC’S
DID THE CODE
RETURN DURING THE
ROAD TEST?
NO
TEST COMPLETE.*
YES
REPLACE TORQUE
CONVERTER.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
241
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-148A
R
O
U
B
L
E
CONTINUED - REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT
LOCK-UP (TJ/XJ BODY WITH 3 SPD AUTO TRANS)
NOTES
C
O
D
E
T
E
S
T
S
242
TEST TC-148A
CONTINUED - REPAIRING - TORQUE CONVERTER CLUTCH - NO RPM DROP AT
LOCK-UP (TJ/XJ BODY WITH 3 SPD AUTO TRANS)
TEST TC-148A
CONTINUED FROM
THE PREVIOUS
PAGE.
REMOVE OIL PAN AND
INSPECT FOR
EXCESSIVE DEBRIS
AND BURNT OIL.
IS THE OIL BURNT
OR DOES THE PAN
CONTAIN EXCESSIVE
DEBRIS?
YES
REPAIR INTERNAL
TRANSMISSION
PROBLEM.*
C
O
D
E
NO
AT THIS TIME THE
CONDITIONS
REQUIRED TO SET
THIS CODE ARE NOT
PRESENT.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
243
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-149A REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO LOW
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
244
TEST TC-149A
REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO LOW
Perform TEST DTC Before Proceeding
START TEST
TC-149A.
KEY ON. USING THE
DRB, READ THE FUEL
LEVEL SENDING UNIT
VOLTAGE.
IS THE FUEL LEVEL
SENDING UNIT
VOLTAGE BELOW
0.4 VOLT?
YES
CONTINUE TEST
TC-149A ON THE
NEXT PAGE.
C
O
D
E
NO
USING THE
SCHEMATIC, WIGGLE
THE FUEL PUMP
MODULE CONNECTOR &
HARNESS.
WAS THERE ANY FUEL
LEVEL SENDING UNIT
SENSOR VOLTAGE
CHANGE?
MONITOR THE DRB
DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
245
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-149A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO LOW
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
246
TEST TC-149A
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO LOW
TEST TC-149A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE
FUEL PUMP MODULE
HARNESS
CONNECTOR.**
C
O
D
E
KEY ON. USING THE
DRB, READ THE FUEL
LEVEL SENDING UNIT
VOLTAGE.
IS THE FUEL LEVEL
SENDING UNIT
VOLTAGE ABOVE 9.5
VOLTS?
YES
REPLACE THE FUEL
PUMP MODULE.*
NO
KEY OFF,
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONN.**
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
MEASURE THE
RESISTANCE OF THE
FUEL LEVEL SENSOR
SIGNAL CIRCUIT TO
GROUND. FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE FUEL
LEVEL SENSOR
SIGNAL CIRCUIT FOR
A SHORT TO
GROUND.*
NO
MEASURE THE
RESISTANCE BETWEEN
THE...
FUEL LEVEL SENSOR
SIGNAL CIRCUIT AND
THE SENSOR GROUND
CKT.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
REPAIR THE FUEL
YES LEVEL SENSOR SIGNAL
CIRCUIT FOR A SHORT
TO THE SENSOR GROUND
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
247
T
E
S
T
S
T TEST TC-150A REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
TJ/XJ BODY
FIG. 1
248
TEST TC-150A
REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-150A.
KEY ON. USING THE
DRB, READ THE FUEL
LEVEL SENDING UNIT
VOLTAGE.
IS THE FUEL LEVEL
SENDING UNIT
VOLTAGE ABOVE 9.9
VOLTS?
YES
CONTINUE TEST
TC-150A ON THE
NEXT PAGE.
NO
USE THE SCHEMATIC AS
A GUIDE AND WIGGLE
THE FUEL PUMP MODULE
CONNECTOR & HARNESS.
MONITOR THE DRB
DISPLAY.
WAS THERE ANY FUEL
LEVEL SENDING UNIT
VOLTAGE CHANGE?
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
249
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
T TEST TC-150A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
250
TEST TC-150A
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
TEST TC-150A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY ON. USING A
VOLTMETER, MEASURE
THE FUEL LEVEL
SENSOR SIGNAL
CIRCUIT...
KEY OFF.
DISCONNECT THE
FUEL PUMP MODULE
HARNESS
CONNECTOR.**
C
O
D
E
AT THE FUEL PUMP
MODULE HARNESS
CONNECTOR.
IS THE VOLTAGE
ABOVE 10.2 VOLTS?
YES
REPAIR THE FUEL
LEVEL SENSOR
CIRCUIT FOR A
SHORT TO VOLTAGE.*
YES
REPLACE THE FUEL
PUMP MODULE.*
YES
REPAIR THE SENSOR
GROUND CIRCUIT FOR
AN OPEN.*
FIG.1 OR 2
NO
CONNECT A JUMPER
BETWEEN FUEL LEVEL
SIGNAL AND SENSOR
GND CKT.
FIG. 1 OR 2
USING THE DRB,
READ THE FUEL
LEVEL SENDING UNIT
VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLT?
NO
MOVE THE JUMPER
WIRE FROM THE
SENSOR GROUND TO A
KNOWN GOOD GROUND.
FIG. 1 OR 2
USING THE DRB,
READ THE FUEL
LEVEL SENDING UNIT
VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLT?
NO
CONTINUE TEST
TC-150A ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
251
T
E
S
T
S
T TEST TC-150A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
252
TEST TC-150A
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT VOLTS TOO HIGH
TEST TC-150A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
T
R
O
U
B
L
E
C
O
D
E
MEASURE THE FUEL
LEVEL SENSOR
SIGNAL CIRCUIT.
BETWEEN THE PCM
AND THE FUEL PUMP
MODULE.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1 OR 2
NO
REPAIR THE FUEL
LEVEL SENSOR
SIGNAL CIRCUIT FOR
AN OPEN.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
253
T
E
S
T
S
T TEST TC-151A REPAIRING - FUEL LEVEL SENDING UNIT NO CHANGE OVER TIME
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
TJ/XJ BODY
FIG. 1
254
TEST TC-151A
REPAIRING - FUEL LEVEL SENDING UNIT NO CHANGE OVER TIME
Perform TEST DTC Before Proceeding
START TEST
TC-151A.
KEY ON. USING THE
DRB, READ THE FUEL
LEVEL SENDING UNIT
VOLTAGE.
IS THE FUEL LEVEL
SENDING UNIT
VOLTAGE BETWEEN
9.4 AND 9.95
VOLTS?
YES
COMTINUE TEST
TC-151A ON THE
NEXT PAGE.
C
O
D
E
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
255
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-151A
R
O
U TJ BODY
B
L
E
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT SENDING UNIT NO
CHANGE OVER TIME
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
256
TEST TC-151A
CONTINUED - REPAIRING - FUEL LEVEL SENDING UNIT SENDING UNIT NO
CHANGE OVER TIME
TEST TC-151A
CONTINUED FROM
PREVIOUS PAGE.
CONNECT A JUMPER
WIRE BETWEEN THE
FUEL LEVEL SENSOR
SIGNAL CIRCUIT
AND...
DISCONNECT THE
FUEL LEVEL SENDING
UNIT HARNESS
CONNECTOR.**
USING THE DRB,
MONITOR THE FUEL
LEVEL SENDING UNIT
VOLTAGE IN THE
FOLLOWING STEP.
A KNOWN GOOD
GROUND.
IS THE FUEL
SENDING UNIT
VOLTAGE BELOW 1.0
VOLT?
C
O
D
E
YES
REPLACE THE FUEL
PUMP MODULE.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1 OR 2
NO
DISCONNECT THE PCM
HARNESS CONNECTOR.**
USE AN OHMMETER IN
THE FOLLOWING STEP.
MEASURE FUEL LEVEL
SENSOR SIGNAL CKT
BETWEEN THE PCM AND
FUEL LEVEL SENDING
UNIT. FIG. 3 OR 4
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE FUEL
LEVEL SENSOR
CIRCUIT FOR HIGH
RESISTANCE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
257
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-153A REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO HIGH
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
258
TEST TC-153A
REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO HIGH
Perform TEST DTC Before Proceeding
START TEST
TC-153A.
KEY ON. USING THE
DRB, READ THE
BATTERY
TEMPERATURE SENSOR
(BTS) VOLTAGE.
IS THE BATTERY
TEMPERATURE SENSOR
VOLTAGE BELOW 0.5
VOLT?
YES
CONTINUE TEST
TC-153A ON THE
NEXT PAGE.
C
O
D
E
NO
IS THE BATTERY
TEMPERATURE
VOLTAGE ABOVE 4.9
VOLTS?
YES
PERFORM TEST
TC-153B.
NO
USE THE SCHEMATIC AS
A GUIDE AND WIGGLE
THE BATTERY TEMP
SENSOR CONNECTOR AND
HARNESS.
WAS THERE ANY
BATTERY TEMP
SENSOR VOLTAGE
CHANGE?
MONITOR THE DRB
DISPLAY.
YES
REPAIR THE
CONNECTOR OR
HARNESS THAT
CAUSED THE VOLTAGE
CHANGE.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
CONNECTORS AND
HARNESS WIRING.
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
259
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-153A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO HIGH
C
O
D
E
T
E
S
T
S
FIG. 1
260
TEST TC-153A
CONTINUED - REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO HIGH
TEST TC-153A
CONTINUED FROM
PREVIOUS PAGE.
KEY OFF.
DISCONNECT THE
BATTERY
TEMPERATURE SENSOR
(BTS) CONN.**
C
O
D
E
KEY ON. USING THE
DRB, READ THE
BATTERY TEMP
SENSOR VOLTAGE.
IS THE BATTERY
TEMPERATURE
VOLTAGE ABOVE 4.0
VOLTS?
YES
REPLACE THE
BATTERY
TEMPERATURE
SENSOR.*
NO
KEY OFF.
DISCONNECT THE PCM
HANRESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE BTS
SIGNAL CIRCUIT TO
GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE BTS
SIGNAL CIRCUIT FOR
A SHORT TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE BETWEEN
THE BTS SIGNAL
CIRCUIT...
AND SENSOR GROUND
CIRCUIT AT BTS
HANRESS CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1
YES
REPAIR THE SENSOR
SIGNAL FOR A SHORT
TO THE SENSOR
GROUND CIRCUIT.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
261
T
E
S
T
S
T TEST TC-153B REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO HIGH
R
O Perform TEST TC-153A Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
262
TEST TC-153B
REPAIRING - BATTERY TEMP SENSOR VOLTAGE TOO LOW/TOO HIGH
Perform TEST TC-153A Before Proceeding
START TEST
TC-153B.
KEY OFF. DISCONNECT
THE BATTERY
TEMPERATURE SENSOR
(BTS) CONNECTOR .**
T
R
O
U
B
L
E
C
O
D
E
KEY ON. USE A
VOLTMETER IN THE
FOLLOWING STEP.
MEASURE THE BTS
SIGNAL CIRCUIT AT
THE BTS HARNESS
CONNECTOR.
FIG. 1
IS THE VOLTAGE
ABOVE 5.5 VOLTS?
YES
REPAIR BTS SIGNAL
CIRCUIT FOR A
SHORT TO VOLTAGE.
IF OK, REPLACE
PCM.*
NO
CONNECT A JUMPER
WIRE ACROSS THE
SENSOR SIGNAL AND
THE SENSOR GND CKT.
FIG. 1
USING THE DRB,
READ THE BATTERY
TEMP SENSOR
VOLTAGE.
IS THE BATTERY
TEMPERATURE
VOLTAGE BELOW 1.0
VOLT?
YES
REPLACE THE
BATTERY
TEMPERATURE
SENSOR.*
NO
MOVE THE JUMPER
WIRE FROM THE
SENSOR GROUND TO
AN ENGINE GROUND.
FIG. 1
WITH THE DRB, READ
THE BTS VOLTAGE.
IS THE VOLTAGE
BELOW 1.0 VOLT?
YES
REPAIR THE SENSOR
GROUND CIRCUIT FOR
AN OPEN.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE BTS
SIGNAL CIRCUIT FROM
THE PCM TO THE BTS
CONN. FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE BATTERY
TEMP SENSOR SIGNAL
CIRCUIT FOR AN
OPEN.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
263
T
E
S
T
S
T TEST TC-155A REPAIRING - 1/1 O2 SENSOR SHORTED TO GROUND
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
XJ BODY
264
TEST TC-155A
T
R
O
U
B
L
E
REPAIRING - 1/1 O2 SENSOR SHORTED TO GROUND
Perform TEST DTC Before Proceeding
START TEST
TC-155A.
REFER TO THE FIGURE
FOR POSSIBLE TROUBLE
CODE CAUSES.
C
O
D
E
FIG. 1
IF ENGINE IS WARM,
TURN ENGINE OFF
FOR 15 MINUTES TO
ALLOW O2 SENSOR TO
COOL DOWN.
T
E
S
T
S
KEY ON, ENGINE
OFF.
USING THE DRB,
MONITOR THE 1/1 O2
SENSOR VOLTAGE.
IS THE 1/1 O2
SENSOR VOLTAGE
BELOW 0.16V?
YES
CONTINUE TEST
TC-155A ON THE
NEXT PAGE.
NO
NOTE: A SHORTED
LOW CONDITION DUE
TO WATER IN THE
SENSOR CONNECTOR,
MAY BE TEMPORARY.
WIGGLE THE 1/1 O2
SENSOR HARNESS AND
MONITOR THE
VOLTAGE.
DID THE 1/1 O2
SENSOR VOLTAGE
CHANGE WHILE
WIGGLING WIRE?
YES
REPAIR THE HARNESS
OR WIRING FOR AN
INTERMITTENT SHORT
TO GROUND.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
THE CONDITION
REQUIRED TO SET
THIS TROUBLE CODE
IS NOT PRESENT AT
THIS TIME.*
**Check connectors - Clean / repair as necessary.
265
T TEST TC-155A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - 1/1 O2 SENSOR SHORTED TO GROUND
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
266
TEST TC-155A
CONTINUED - REPAIRING - 1/1 O2 SENSOR SHORTED TO GROUND
CONTINUE TEST
TC-155A FROM
THE PREVIOUS
PAGE.
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT OR
MISWIRED?
DISCONNECT THE 1/1
O2 SENSOR.**
YES
REPAIR OR REPLACE
AS NECESSARY.*
C
O
D
E
NO
WITH THE DRB, READ
THE 1/1 O2 SENSOR
VOLTAGE.
IS THE VOLTAGE
BELOW 0.16 VOLTS?
NO
REPLACE THE 1/1 O2
SENSOR.*
YES
REPAIR OR REPLACE
AS NECESSARY.*
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT OR
MISWIRED?
NO
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE 1/1 O2
SENSOR SIGNAL
CIRCUIT FROM THE PCM
CONNECTOR TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE 1/1 O2
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
NO
MEASURE THE 1/1 O2
SENSOR SIGNAL TO
THE SENSOR GROUND
CIRCUIT...
AT THE 1/1 O2
SENSOR HARNESS
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1 OR 2
YES
REPAIR THE 1/1 O2
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO SENSOR
GROUND CIRCUIT.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
267
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-156A REPAIRING - 1/2 O2 SENSOR SHORTED TO GROUND
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
XJ BODY
268
TEST TC-156A
T
R
O
U
B
L
E
REPAIRING - 1/2 O2 SENSOR SHORTED TO GROUND
Perform TEST DTC Before Proceeding
START TEST
TC-156A.
REFER TO THE FIGURE
FOR POSSIBLE TROUBLE
CODE CAUSES.
C
O
D
E
FIG. 1
IF ENGINE IS WARM
TURN ENGINE OFF
FOR 15 MINUTES TO
ALLOW O2 SENSOR TO
COOL DOWN.
T
E
S
T
S
KEY ON, ENGINE
OFF.
WITH THE DRB,
MONITOR THE 1/2 O2
SENSOR VOLTAGE.
IS THE 1/2 O2
SENSOR VOLTAGE
BELOW 0.16V?
YES
CONTINUE TEST
TC-156A ON THE
NEXT PAGE.
NO
NOTE: A SHORTED
LOW CONDITION DUE
TO WATER IN THE
SENSOR CONNECTOR,
MAY BE TEMPORARY.
DID THE 1/2 O2
SENSOR VOLTAGE
CHANGE WHILE
WIGGLING THE
HARNESS?
WIGGLE THE 1/2 O2
SENSOR HARNESS AND
MONITOR VOLTAGE.
YES
REPAIR THE HARNESS
OR WIRING FOR AN
INTERMITTENT SHORT
TO GROUND.*
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
THE CONDITION
REQUIRED TO SET
THIS TROUBLE CODE
IS NOT PRESENT AT
THIS TIME.*
**Check connectors - Clean / repair as necessary.
269
T TEST TC-156A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - 1/2 O2 SENSOR SHORTED TO GROUND
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
270
TEST TC-156A
CONTINUED - REPAIRING - 1/2 O2 SENSOR SHORTED TO GROUND
CONTINUE TEST
TC-156A FROM
THE PREVIOUS
PAGE.
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT OR
MISWIRED?
KEY OFF.
DISCONNECT THE 1/2
O2 SENSOR.**
YES
REPAIR OR REPLACE
AS NECESSARY.*
C
O
D
E
NO
KEY ON. USING THE
DRB, READ THE 1/2
O2 SENSOR VOLTAGE.
IS THE VOLTAGE
BELOW 0.16 VOLTS?
NO
REPLACE THE 1/2 O2
SENSOR.*
YES
REPAIR OR REPLACE
AS NECESSARY.*
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT OR
MISWIRED?
NO
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE 1/2 O2
SENSOR SIGNAL
CIRCUIT FROM THE PCM
CONNECTOR TO GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE 1/2 O2
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO GROUND.*
NO
MEASURE THE 1/2 O2
SENSOR SIGNAL
CIRCUIT TO THE
SENSOR GROUND
CIRCUIT...
AT THE 1/2 O2
SENSOE HARNESS
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
FIG. 1 OR 2
YES
REPAIR THE 1/2 O2
SENSOR SIGNAL
CIRCUIT FOR A
SHORT TO SENSOR
GROUND.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
271
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-157A REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
R
O Perform TEST DTC Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
272
TEST TC-157A
T
R
O
U
B
L
E
REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
Perform TEST DTC Before Proceeding
START TEST
TC-157A.
SEE FIGURE 1 FOR
TROUBLE CODE
INFORMATION.
C
O
D
E
USING THE DRB, CHECK
THE DISTRIBUTOR
POSITION WITH SET
SYNC SIGNAL UNDER
MISC. FUNCTIONS.
IS THE DISTRIBUTOR
POSITION IN RANGE?
NO
SET DISTRIBUTOR
POSITION WITH DRB
USING STEPS GIVEN
IN TEST NTC-13A.*
YES
NOTE: CMP OR CKP
SIGNAL LOSS CAN BE
DETECTED BY A RPM
CHANGE, TROUBLE
CODE, OR...
DO YOU WANT TO
DIAGNOSE CMP OR
CKP SIGNAL LOSS
WITH AN
OSCILLOSCOPE?
PATTERN ON THE
OSCILLOSCOPE.
NO
PERFORM TEST
TC-157B.
NO
CONTINUE TEST
TC-157A ON THE
NEXT PAGE.
YES
AT THE CMP SENSOR
BACKPROBE THE
SENSOR SIGNAL CKT
WITH THE VOLTAGE
LEAD.
START THE ENGINE
AND OBSERVE THE
CMP SENSOR VOLTAGE
PATTERN ON THE
SCOPE.
ARE THERE ANY
CAMSHAFT POSITION
SENSOR SIGNALS
MISSING?
YES
KEY OFF.
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
DISCONNECT THE CMP
SENSOR
CONNECTOR.**
YES
REPAIR AS
NECESSARY.*
YES
REPAIR AS
NECESSARY.*
NO
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
NO
PERFORM TEST
TC-157C.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
273
T
E
S
T
S
T TEST TC-157A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
C
O
D
E
T
E
S
T
S
274
TEST TC-157A
CONTINUED - REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
TEST TC-157A
CONTINUED FROM
THE PREVIOUS
PAGE.
AT PCM BACKPROBE
CMP SENSOR SIGNAL
CKT WITH SCOPE’S
VOLTAGE
MEASUREMENT LEAD.
T
R
O
U
B
L
E
C
O
D
E
WHILE OBSERVING
THE SCOPE PATTERN,
WIGGLE CMP CKT
FROM SENSOR TO
PCM.
WERE ANY SIGNALS
MISSING WHEN THE
WIGGLE TEST WAS
CONDUCTED?
YES
NOTE WHERE
WIGGLING THE WIRES
CAUSED A MISSING
CMP SENSOR SIGNAL.
NO
KEY OFF.
WITH THE SCOPE’S
VOLTAGE
MEASUREMENT LEAD.
AT THE CRANKSHAFT
POSITION SENSOR,
BACKPROBE THE CKP
SENSOR SIGNAL
CIRCUIT...
REPAIR CAMSHAFT
AND CRANKSHAFT
WIRE HARNESS AS
NECESSARY.*
START THE ENGINE
AND OBSERVE THE
CKP SENSOR VOLTAGE
PATTERN ON THE
SCOPE.
ARE ANY CRANKSHAFT
POSITION SENSOR
SIGNALS MISSING?
NO
CONTINUE TEST
TC-157A ON THE
NEXT PAGE.
YES
KEY OFF.
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
DISCONNECT THE CKP
SENSOR.**
YES
REPAIR AS
NECESSARY.*
YES
REPAIR AS
NECESSARY.*
NO
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
NO
PERFORM TEST
TC-157D.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
275
T
E
S
T
S
T TEST TC-157A
R
O
U
B
L
E
CONTINUED - REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
276
TEST TC-157A
CONTINUED - REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
TEST TC-157A
CONTINUED FROM
THE PREVIOUS
PAGE.
AT PCM, BACKPROBE
CKP SENSOR SIGNAL
CKT WITH SCOPE’S
VOLTAGE
MEASUREMENT LEAD.
T
R
O
U
B
L
E
C
O
D
E
WHILE OBSERVING
THE SCOPE PATTERN,
WIGGLE CKP SENSOR
CIRCUIT FROM
SENSOR TO PCM.
WERE ANY CKP
SENSOR SIGNALS
MISSING WHEN THE
WIGGLE TEST WAS
CONDUCTED?
YES
NOTE WHERE
WIGGLING THE WIRES
CAUSED A MISSING
CKP SENSOR SIGNAL.
NO
*Perform Verification TEST VER-2A.
THE CONDITION
REQUIRED TO SET
THE TROUBLE CODE
IS NOT PRESENT.
FIG. 1
REPAIR THE
CAMSHAFT AND
CRANKSHAFT WIRE
HARNESS AS
NECESSARY.*
REFER TO GENERAL
INFO 3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
277
T
E
S
T
S
T TEST TC-157B REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
R
O Perform TEST TC-157A Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
278
TEST TC-157B
REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
Perform TEST TC-157A Before Proceeding
START TEST
TC-157B.
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
YES
REPAIR AS
NECESSARY.*
C
O
D
E
NO
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
DISCONNECT THE CMP
SENSOR
CONNECTOR.**
YES
REPAIR AS
NECESSARY.*
YES
REPAIR AS
NECESSARY.*
NO
IS ANY TERMINAL
CORRODED, DAMAGED,
PUSHED OUT, OR
MISWIRED?
DISCONNECT THE CKP
SENSOR
CONNECTOR.**
NO
RECONNECT THE PCM,
CKP AND CMP
CONNECTORS.
START THE ENGINE
AND LET IT IDLE.
WITH THE DRB,
MONITOR THE RPM
WHILE WIGGLING CMP
& CKP HARNESS
WIRING.
DOES THE ENGINE
SPEED CHANGE WHEN
WIGGLING THE WIRE
HARNESS?
YES
NOTE WHERE WIGGLING
WIRES CAUSED A ENG
SPEED CHANGE &
REPAIR WIRE HARNESS
AS NECESSARY.*
NO
YES
NO PROBLEM HAS
BEEN FOUND. DO YOU
WANT TO WIGGLE
ANOTHER WIRE
HARNESS SECTION?
NO
THE CONDITION
REQUIRED TO SET
THE TROUBLE CODE
IS NOT PRESENT
FIG. 1
REFER TO GENERAL
INFO 3.3.2 FOR
INFORMATION ON
INACTIVE TROUBLE
CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
279
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-157C REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
R
O Perform TEST TC-157A Before Proceeding
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
280
TEST TC-157C
T
R
O
U
B
L
E
REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
Perform TEST TC-157A Before Proceeding
START TEST
TC-157C.
REMOVE THE
DISTRIBUTOR CAP.
FIG. 1
C
O
D
E
INSPECT THE ROTOR
AND ROTOR DRIVE
SYSTEM FOR LOOSENESS
PER SERVICE MANUAL
INSTRUCTIONS.
IS THE ROTOR AND
ROTOR DRIVE SYSTEM
OK?
NO
REPAIR THE LOOSE
DISTRIBUTOR ROTOR
OR ROTOR DRIVE
SYSTEM AS
NECESSARY.*
YES
REPLACE THE
CAMSHAFT POSITION
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
281
T
E
S
T
S
T TEST TC-157D REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
R
O Perform TEST TC-157A Before Proceeding
TJ/XJ BODY 2.5L AND 4.0L
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
282
TEST TC-157D
T
R
O
U
B
L
E
REPAIRING - INTERMITTENT LOSS OF CMP OR CKP
Perform TEST TC-157A Before Proceeding
START TEST
TC-157D.
REMOVE THE
CRANKSHAFT
POSITION SENSOR.
FIG. 1
C
O
D
E
INSPECT THE
FLYWHEEL FOR
DAMAGE.
IS THE FLYWHEEL
DAMAGED?
YES
REPAIR AS
NECESSARY.*
NO
REPLACE THE
CRANKSHAFT
POSITION SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
283
T
E
S
T
S
T TEST TC-225A REPAIRING - NO CDD BUS MESSAGE FROM THE MIC
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
284
TEST TC-225A
T
R
O
U
B
L
E
REPAIRING - NO CDD BUS MESSAGE FROM THE MIC
Perform TEST DTC Before Proceeding
START TEST
TC-225A.
C
O
D
E
KEY ON.
USING THE DRB,
ERASE CODES.
CYCLE THE KEY ON AND
OFF SEVERAL TIMES.
KEY ON.
USING THE DRB,
READ CODES.
DID THE "NO
CCD/PCI BUS
MESSAGE FROM MIC"
RETURN?
YES
CONTINUE TEST
TC-225A ON THE
NEXT PAGE.
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
USING THE SCHEMATIC
AS A GUIDE, INSPECT
THE WIRING AND
CONNECTORS.
FIG. 1 OR 2
WERE ANY PROBLEMS
FOUND?
YES
REPAIR AS
NECESSARY.*
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
285
T
E
S
T
S
T TEST TC-225A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING NO CCD BUS MESSAGE FROM MIC
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
286
TEST TC-225A
T
R
O
U
B
L
E
CONTINUED - REPAIRING NO CCD BUS MESSAGE FROM MIC
TEST TC-225A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT PCM
HARNESS
CONNECTOR.**
KEY OFF.
C
O
D
E
DISCONNECT
INSTRUMENT CLUSTER
CONNECTOR.**
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
MEASURE THE
RESISTANCE OF THE
CCD(+) CKT BETWEEN
PCM HARNESS
CONNECTOR...
AND THE INSTRUMENT
CLUSTER HARNESS
CONNECTOR.
T
E
S
T
S
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE CCD(+)
CIRCUIT FOR AN
OPEN.*
NO
REPAIR THE CCD(-)
CIRCUIT FOR AN
OPEN.*
FIG. 1 OR 2
YES
MEASURE THE
RESISTANCE OF THE
CCD(-) CKT BETWEEN
THE PCM HARNESS
CONNECTOR...
AND THE INSTRUMENT
CLUSTER HARNESS
CONNECTOR
IS THE RESISTANCE
BELOW 5.0 OHMS?
FIG. 1 OR 2
YES
REPLACE THE
INSTRUMENT
CLUSTER.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
287
T TEST TC-226A REPAIRING - NO CCD BUS MESSAGE RECEIVED FROM SKIM
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
288
TEST TC-226A
T
R
O
U
B
L
E
REPAIRING - NO CCD BUS MESSAGE RECEIVED FROM SKIM
Perform TEST DTC Before Proceeding
KEY ON.
START TEST
TC-226A.
USING THE DRB,
ERASE CODES.
C
O
D
E
ATTEMPT TO START
THE ENGINE.
DOES THE DRB
DISPLAY THIS CODE?
READ CODES.
YES
CONTINUE TEST
TC-226A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
289
T
E
S
T
S
T TEST TC-226A
R
O
U
TJ BODY
B
L
E
CONTINUED - REPAIRING - NO CCD BUS MESSAGE RECEIVED FROM SKIM
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
290
TEST TC-226A
CONTINUED - REPAIRING - NO CCD BUS MESSAGE RECEIVED FROM SKIM
TEST TC-226A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
ATTEMPT TO
COMMUNICATE WITH
THE SKIM MODULE.
CAN YOU
COMMUNICATE WITH
THE SKIM?
NO
REFER TO
"SENTRY KEY
IMMOBILIZER"
SECTION
"TEST DTC".
C
O
D
E
YES
T
E
S
T
S
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
DISCONNECT THE
SKIM HARNESS
CONNECTOR.**
MEASURE THE CCD
BUS(+) CIRCUIT
BETWEEN THE PCM AND
THE SKIM MODULE.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
CCD BUS(+)
CIRCUIT.*
NO
REPAIR THE OPEN
CCD BUS(-)
CIRCUIT.*
YES
MEASURE THE CCD
BUS(-) CIRCUIT
BETWEEN THE PCM AND
THE SKIM MODULE.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-1A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
291
T TEST TC-232A REPAIRING - INVALID OR WRONG KEY MESSAGE FROM SKIM
R
O Perform TEST DTC Before Proceeding
U
TJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
292
TEST TC-232A
T
R
O
U
B
L
E
REPAIRING - INVALID OR WRONG KEY MESSAGE FROM SKIM
Perform TEST DTC Before Proceeding
START TEST
TC-232A.
WITH THE DRB,
ERASE CODES.
C
O
D
E
ATTEMPT TO START
AND IDLE THE
ENGINE FOR 1
MINUTE.
DOES THE DRB
DISPLAY THIS CODE?
READ CODES.
YES
CONTINUE TEST
TC-232A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
INSPECT THE WIRING
AND CONNECTORS
ASSOCIATED WITH
THE PCI BUS
CIRCUIT.
WERE ANY PROBLEMS
FOUND?
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
293
T
E
S
T
S
T TEST TC-232A
R
O
U
TJ BODY
B
L
E
REPAIRING - INVALID OR WRONG KEY MESSAGE FROM SKIM
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
294
TEST TC-232A
REPAIRING - INVALID OR WRONG KEY MESSAGE FROM SKIM
TEST TC-232A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
ATTEMPT TO
COMMUNICATE WITH
THE SKIM.
CAN YOU
COMMUNICATE WITH
THE SKIM?
NO
PERFORM
SK-TEST DTC.
C
O
D
E
YES
WITH THE DRB,
CHECK FOR SKIM
TROUBLE CODES.
ARE THERE ANY SKIM
TROUBLE CODES?
YES
PERFORM
SK-TEST DTC.
NO
WITH THE DRB
DISPLAY THE VIN
THAT IS PROGRAMMED
IN THE PCM.
IS THE CORRECT VIN
PROGRAMMED IN THE
PCM?
NO
REPLACE PCM
AND
PROGRAM CORRECT
VIN INTO PCM AND
RETEST.*
YES
KEY OFF.
CLEAR ALL CODES.
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
ATTEMPT TO START
AND IDLE THE
ENGINE.
USING THE DRB,
READ PCM TROUBLE
CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
REPLACE THE SKIM.*
NO
TEST COMPLETE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
295
T
R
O
U
B
L
E
T
E
S
T
S
T TEST TC-235A REPAIRING - OIL PRESSURE SENSOR LOW EXCEEDED
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
296
TEST TC-235A
T
R
O
U
B
L
E
REPAIRING - OIL PRESSURE SENSOR LOW EXCEEDED
Perform TEST DTC Before Proceeding
KEY ON.
START TEST
TC-235A.
USING THE DRB,
ERASE CODES.
C
O
D
E
CYCLE THE KEY ON
AND OFF SEVERAL
TIMES.
USING THE DRB,
READ CODES.
DID THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
TC-119A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE SCHEMATIC
AS A GUIDE, INSPECT
THE WIRING AND
CONNECTORS.
FIG. 2
WERE ANY PROBLEMS
FOUND?
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
297
T
E
S
T
S
T TEST TC-235A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - OIL PRESSURE SENSOR LOW EXCEEDED
C
O
D
E
T
E
S
T
S
FIG. 1
298
TEST TC-235A
CONTINUED - REPAIRING - OIL PRESSURE SENSOR LOW EXCEEDED
TEST TC-235A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE OIL
PRESSURE SENSOR
HARNESS
CONNECTOR.**
T
R
O
U
B
L
E
C
O
D
E
KEY ON.
USE A VOLTMETER IN
THE FOLLOWING
STEP.
MEASURE THE VOLTAGE
OF THE OIL PRESSURE
SENSOR SIGNAL.
IS THE VOLTAGE
BETWEEN 4.8 AND
5.3 VOLTS?
YES
REPLACE THE OIL
PRESSURE SENSOR.*
FIG. 1
NO
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
MEASURE THE
RESISTANCE OF
THE...
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
OIL PRESSURE
SENSOR SIGNAL
CIRCUIT TO GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
OIL PRESSURE
SENSOR SIGNAL
CIRCUIT.**
NO
MEASURE THE
RESISTANCE BETWEEN
THE...
OIL PRESSURE SENSOR
SIGNAL CKT AND THE
SENSOR GROUND CKT.
IS THE RESISTANCE
BELOW 5.0 OHMS?
FIG. 1
YES
REPAIR THE OIL
PRESSURE SENSOR
SIGNAL CIRCUIT FOR A
SHORT TO THE SENSOR
GROUND CIRCIUT.**
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
299
T
E
S
T
S
T TEST TC-236A REPAIRING OIL PRESSURE SENSOR HIGH EXCEEDED
R
O Perform TEST DTC Before Proceeding
U
TJ/XJ BODY
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
300
TEST TC-236A
T
R
O
U
B
L
E
REPAIRING OIL PRESSURE SENSOR HIGH EXCEEDED
Perform TEST DTC Before Proceeding
KEY ON.
START TEST
TC-236A.
USING THE DRB,
ERASE CODES.
C
O
D
E
CYCLE THE KEY ON AND
OFF SEVERAL TIMES.
KEY ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
TC-236A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME, THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE SCHEMATIC
AS A GUIDE, INSPECT
THE WIRING AND
CONNECTORS.
FIG. 2
WERE ANY PROBLEMS
FOUND?
NO
REFER TO GENERAL
INFO 3.3.2 FOR
ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-2A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
301
T
E
S
T
S
T TEST TC-236A
R
O
TJ/XJ BODY
U
B
L
E
CONTINUED - REPAIRING - OIL PRESSURE SENSOR HIGH EXCEEDED
C
O
D
E
T
E
S
T
S
FIG. 1
302
TEST TC-236A
CONTINUED - REPAIRING - OIL PRESSURE SENSOR HIGH EXCEEDED
TEST TC-236A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE OIL
PRESSURE SENSOR
HARNESS
CONNECTOR.**
KEY OFF.
T
R
O
U
B
L
E
C
O
D
E
KEY ON.
USE A VOLTMETER IN
THE FOLLOWING
STEPS.
MEASURE THE
VOLTAGE OF THE OIL
PRESSURE SENSOR
SIGNAL CIRCUIT.
FIG. 1
IS THE VOLTAGE
ABOVE 5.5 VOLTS?
NO
CONTINUE TEST
TC-236A ON THE
NEXT PAGE.
YES
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
KEY ON. MEASURE THE
VOLTAGE OF THE OIL
PRESSURE SENSOR
SIGNAL CIRCUIT.
FIG. 1
IS THE VOLTAGE
BELOW 0.5 VOLT?
NO
REPAIR THE SHORT
TO VOLTAGE IN THE
OIL PRESSURE
SENSOR SIGNAL
CIRCUIT.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
303
T
E
S
T
S
T TEST TC-236A
R
O
U
TJ/XJ BODY
B
L
E
CONTINUED - REPAIRING OIL PRESSURE SENSOR HIGH EXCEEDED
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
304
TEST TC-236A
CONTINUED - REPAIRING OIL PRESSURE SENSOR HIGH EXCEEDED
TEST TC-236A
CONTINUED FROM
PREVIOUS PAGE.
WAS THE VOLTAGE
MEASURED IN THE
PREVIOUS STEP
BETWEEN 4.8 AND
5.3 VOLTS?
YES
C
O
D
E
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF
THE...
IS THE RESISTANCE
BELOW 5.0 OHMS?
SENSOR GROUND
CIRCUIT TO GROUND.
NO
REPAIR THE OPEN IN
THE OIL PRESSURE
SENSOR GROUND
CIRCUIT.*
YES
REPLACE THE OIL
PRESSURE SENSOR.*
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF
THE...
OIL PRESSURE
SENSOR SIGNAL
CIRCUIT.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE OIL PRESSURE
SENSOR SIGNAL
CIRCUIT.*
FIG. 2
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
**Check connectors - Clean / repair as necessary.
305
T
E
S
T
S
S
E
N
T
R
Y
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
TEST SK-1A
IDENTIFYING SENTRY KEY IMMOBILIZER SYSTEM
Perform TEST DTC Before Proceeding
DIAGNOSTIC TROUBLE CODE (DTC) DISPLAYED
DIAGNOSTIC TEST
ANTENNA FAILURE
**
COP FAILURE
**
EEPROM FAILURE
**
EMS STATUS FAILURE
SK-2A
INTERNAL FAULT
**
RAM FAILURE
**
ROLLING CODE FAILURE
SK-3A
SERIAL LINK EXTENERAL FAULT
SK-4A
SERIAL LINK INTERNAL
**
STACK OVERFLOW FAILURE
**
TRANSPONDER COMMUNICATION FAILURE
SK-5A
TRANSPONDER CRC (CYCLE REDUNDANCY CHECK) FAILURE
SK-6A
TRANSPONDER ID MISMATCH
SK-7A
TRANSPONDER RESPONSE MISMATCH
SK-8A
VIN MISMATCH
SK-9A
**These trouble codes indicate an internal SKIM fault. Using the DRB, clear SKIM trouble code(s).
Perform several key cycles, leaving the key on for a minimum of 30 seconds per cycle. Using the
DRB, read SKIM trouble codes. If the trouble code is present, replace the SKIM.
NOTE: An intermittent start and stall condition accompanied with a transponder DTC can be caused
by the presence of a non-programmed key or key programmed to another vehicle, near the SKIM
antenna (ignition halo). This can occur if the customer has a key holder (ring) that contains more
than one key equipped with a transponder chip.
After replacement of the Sentry Key Immobilizer Module (SKIM) see GENERAL INFORMATION
SECTION 8.0 for SKIM initialization.
NOTE: For all component locations, REFER TO GENERAL INFORMATION Section 4.0 in this
manual.
306
TEST SK-1A
IDENTIFYING SENTRY KEY IMMOBILIZER SYSTEM
Perform TEST DTC Before Proceeding
NOTE: The Sentry Key Immobilizer System (SKIS) diagnosis may require usage of the customer’s
additional keys to verify the cause of the system failure. In the event that the Sentry Key Immobilizer
Module (SKIM) needs replacing, all of the keys previously programmed into the SKIM’s memory
must be programmed into the new SKIM. THEREFORE IT IS IMPORTANT THAT ALL OF THE
CUSTOMER’S KEYS PROGRAMMED FOR THE VEHICLE BE OBTAINED PRIOR TO BEGINNING VEHICLE DIAGNOSIS.
NOTE: It is necessary to obtain the four-digit Personal Identification Number (PIN) from the
customer or the vehicle invoice. The PIN is required to perform certain SKIM tasks using the DRB.
NOTE: It is very important that the PCM is programmed with the correct Vehicle Identification
Number (VIN). Incorrect VIN programming may result in incorrect diagnosis and unnecessary
component replacement. Use the DRB to verify the correct VIN and country code in the SKIM.
1. The battery must be fully charged for any test in this manual.
2. Attempt to start the engine. Crank for up to 10 seconds if necessary.
3. Connect the DRB to the diagnostic connector and select ‘‘Theft Alarm’’ then ‘‘SKIM’’.
If the DRB displays ‘‘No Response’’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .perform test 1B
NOTE: If the DRB screen is blank or has a DRB error message displayed, go to General
Information Section 3.5 in this manual.
4. With the DRB, read and record SKIM trouble codes.
5. If diagnostic trouble code(s) are displayed, refer to the diagnostic trouble code list on the next
page for the appropriate test.
307
S
E
N
T
R
Y
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
S
E
N
T
R
Y
TEST SK-1B
SKIM COMMUNICATION
Perform TEST SK-1A Before Proceeding
TJ BODY
XJ BODY
TJ BODY
XJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
FIG. 1
FIG. 2
308
TEST SK-1B
SKIM COMMUNICATION
Perform TEST SK-1A Before Proceeding
START TEST.
USING THE DRB,
ATTEMPT TO
COMMUNICATE WITH
THE PCM CONTROL
MODULE.
CAN YOU
COMMUNICATE WITH
THE PCM?
NO
REFER TO TEST
NS-6A TO
DIAGNOSE A NO
RESPONSE
CONDITION.
YES
TURN IGNITION OFF.
DISCONNECT THE
SKIM MODULE
HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE GROUND
CIRCUIT CAVS 2 AND
4 AT THE SKIM
CONN. FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS FOR
BOTH GROUND
CIRCUITS?
NO
REPAIR THE OPEN
GROUND CIRCUIT(S)
THAT DID NOT
MEASURE BELOW 5.0
OHMS.*
YES
USING A VOLTMETER,
MEASURE THE BATTERY
SUPPLY CIRCUIT.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN
BATTERY SUPPLY
CIRCUIT.*
S
E
N
T
R
Y
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
FIG. 1 OR 2
YES
TURN IGNITION ON.
USING A VOLTMETER,
MEASURE THE IGNITION
SUPPLY CIRCUIT.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN
IGNITION SUPPLY
CIRCUIT.*
NO
REPAIR THE OPEN
CCD BUS
CIRCUIT(S).*
NO
REPLACE THE SKIM
MODULE.*
FIG. 1 OR 2
YES
WAIT 2 MINUTES
BEFORE CONTINUING.
WITH THE IGNITION
STILL ON...
MEASURE BOTH CCD
BUS CIRCUITS AT
THE SKIM MODULE
HARNESS CONNECTOR.
FIG. 1 OR 2
IS THE VOLTAGE
BETWEEN 2.3 AND
2.6 FOR BOTH
MEASURES?
YES
TURN IGNITION OFF.
RECONNECT THE SKIM
HARNESS CONNECTOR.
KEY ON.
CAN YOU
COMMUNICATE WITH
THE SKIM MODULE?
ATTEMPT TO
COMMUNICATE WITH
THE SKIM MODULE.
YES
TEST COMPLETE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
309
S
Y
S
T
E
M
S
E
N
T
R
Y
TEST SK-2A
REPAIRING - PCM STATUS FAILURE
Perform TEST SK-1A Before Proceeding
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
XJ BODY
S
Y
S
T
E
M
FIG. 1
310
TEST SK-2A
S
E
N
T
R
Y
REPAIRING - PCM STATUS FAILURE
Perform TEST SK-1A Before Proceeding
START TEST
SK-2A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-2A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG.1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
311
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-2A
CONTINUED - REPAIRING - PCM STATUS FAILURE
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
XJ BODY
312
TEST SK-2A
S
E
N
T
R
Y
CONTINUED - REPAIRING - PCM STATUS FAILURE
TEST SK-2A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE SCHEMATIC
AS A GUIDE, INSPECT
THE CCD BUS CIRCUITS
BETWEEN THE PCM AND
SKIM MODULE.
TURN IGNITION OFF.
K
E
Y
CHECK THE WIRING
AND CONNECTORS FOR
POOR TERMINAL
CONTACT, CORROSION
OR DAMAGE.
ARE ANY OF THESE
CONDITIONS
PRESENT?
YES
REPAIR AS
NECESSARY.*
NO
REPLACE THE SKIM
MODULE.**
USING THE DRB,
ERASE CODES.
S
Y
S
T
E
M
SEE GENERAL INFO 8.0
DRIVE VEHICLE.
I
M
M
O
B
I
L
I
Z
E
R
USING THE DRB,
CHECK CODES.
DOES THIS CODE
APPEAR?
PERFORM SEVERAL
KEY CYCLES.
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
TEST COMPLETE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
313
S
E
N
T
R
Y
TEST SK-3A
REPAIRING - ROLLING CODE FAILURE
Perform TEST SK-1A Before Proceeding
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
XJ BODY
S
Y
S
T
E
M
FIG. 1
314
TEST SK-3A
S
E
N
T
R
Y
REPAIRING - ROLLING CODE FAILURE
Perform TEST SK-1A Before Proceeding
START TEST
SK-3A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-3A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG.1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
315
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-3A
CONTINUED - REPAIRING ROLLING CODE FAILURE
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
XJ BODY
S
Y
S
T
E
M
316
TEST SK-3A
S
E
N
T
R
Y
CONTINUED - REPAIRING ROLLING CODE FAILURE
TEST SK-3A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE SCHEMATIC
AS A GUIDE, INSPECT
THE CCD BUS CKT(S)
BETWEEN THE PCM AND
SKIM MODULE.
TURN IGNITION OFF.
K
E
Y
CHECK THE WIRING
AND CONNECTORS FOR
POOR TERMINAL
CONTACT, CORROSION
OR DAMAGE.
ARE ANY OF THESE
CONDITIONS
PRESENT?
YES
REPAIR AS
NECESSARY.*
NO
REPLACE THE SKIM
MODULE.**
USING DRB ERASE
CODES.
S
Y
S
T
E
M
SEE GENERAL INFO 8.0
DRIVE VEHICLE.
I
M
M
O
B
I
L
I
Z
E
R
USING THE DRB,
CHECK CODES.
DOES THIS CODE
APPEAR?
PERFORM SEVERAL
KEY CYCLES.
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
TEST COMPLETE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
317
S
E
N
T
R
Y
TEST SK-4A
REPAIRING - SERIAL LINK EXTERNAL FAILURE
Perform TEST SK-1A Before Proceeding
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
XJ BODY
S
Y
S
T
E
M
FIG. 1
318
TEST SK-4A
S
E
N
T
R
Y
REPAIRING - SERIAL LINK EXTERNAL FAILURE
Perform TEST SK-1A Before Proceeding
START TEST
SK-4A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-4A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG.1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
319
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-4A
CONTINUED - REPAIRING - SERIAL LINK EXTERNAL FAILURE
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
XJ BODY
320
TEST SK-4A
S
E
N
T
R
Y
CONTINUED - REPAIRING - SERIAL LINK EXTERNAL FAILURE
TEST SK-4A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE SCHEMATIC
AS A GUIDE, INSPECT
THE CCD BUS CKT(S)
BETWEEN THE PCM AND
SKIM MODULE.
TURN IGNITION OFF.
K
E
Y
CHECK THE WIRING
AND CONNECTORS FOR
POOR TERMINAL
CONTACT, CORROSION
OR DAMAGE.
ARE ANY OF THESE
CONDITIONS
PRESENT?
YES
REPAIR AS
NECESSARY.*
NO
REPLACE THE SKIM
MODULE.**
USING DRB ERASE
CODES.
S
Y
S
T
E
M
SEE GENERAL INFO 8.0
DRIVE VEHICLE.
I
M
M
O
B
I
L
I
Z
E
R
USING THE DRB,
CHECK CODES.
DOES THIS CODE
APPEAR?
PERFORM SEVERAL
KEY CYCLES.
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
TEST COMPLETE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
321
S
E
N
T
R
Y
TEST SK-5A
REPAIRING - TRANSPONDER COMMUNICATION FAILURE
Perform TEST SK-1A Before Proceeding
TJ BODY
XJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
FIG. 1
322
TEST SK-5A
S
E
N
T
R
Y
REPAIRING - TRANSPONDER COMMUNICATION FAILURE
Perform TEST SK-1A Before Proceeding
START TEST
SK-5A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-5A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
323
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-5A
CONTINUED - REPAIRING - TRANSPONDER COMMUICATION FAILURE
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
324
TEST SK-5A
CONTINUED - REPAIRING - TRANSPONDER COMMUICATION FAILURE
TEST SK-5A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
CLEAR CODES.
USING THE DRB,
ATTEMPT TO REPROGRAM
THE IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE IGNITION
KEY WITH A KNOWN
GOOD KEY.
USING THE DRB,
PROGRAM THE KNOWN
GOOD IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
USING THE DRB,
CLEAR CODES.
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE THE SKIM
MODULE.*
*Perform Verification TEST VER-1A.
S
E
N
T
R
Y
**Check connectors - Clean / repair as necessary.
325
S
E
N
T
R
Y
TEST SK-6A
REPAIRING - TRANSPONDER CRC (CYCLIC REDUNDANCY CHECK) FAILURE
Perform TEST SK-1A Before Proceeding
TJ BODY
XJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
FIG. 1
326
TEST SK-6A
REPAIRING - TRANSPONDER CRC (CYCLIC REDUNDANCY CHECK) FAILURE
Perform TEST SK-1A Before Proceeding
START TEST
SK-6A.
USING THE DRB,
ERASE CODES.
S
E
N
T
R
Y
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-6 ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
327
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-6A
CONTINUED - REPAIRING - TRANSPONDER CRC (CYCLIC REDUNDANCY CHECK)
FAILURE
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
328
TEST SK-6A
CONTINUED - REPAIRING - TRANSPONDER CRC (CYCLIC REDUNDANCY CHECK)
FAILURE
TEST SK-6A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
CLEAR CODES.
USING THE DRB,
ATTEMPT TO REPROGRAM
THE IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE IGNITION
KEY WITH A KNOWN
GOOD KEY.
USING THE DRB,
PROGRAM THE KNOWN
GOOD IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
USING THE DRB,
CLEAR CODES.
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE THE SKIM
MODULE.*
*Perform Verification TEST VER-1A.
S
E
N
T
R
Y
**Check connectors - Clean / repair as necessary.
329
S
E
N
T
R
Y
TEST SK-7A
REPAIRING - TRANSPONDER ID MISMATCH
Perform TEST SK-1A Before Proceeding
TJ BODY
XJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
FIG. 1
330
TEST SK-7A
S
E
N
T
R
Y
REPAIRING - TRANSPONDER ID MISMATCH
Perform TEST SK-1A Before Proceeding
START TEST
SK-7A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-7A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
331
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-7A
CONTINUED - REPAIRING - TRANSPONDER ID MISMATCH
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
332
TEST SK-7A
S
E
N
T
R
Y
CONTINUED - REPAIRING - TRANSPONDER ID MISMATCH
TEST SK-7A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
CLEAR CODES.
USING THE DRB,
ATTEMPT TO REPROGRAM
THE IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE IGNITION
KEY WITH A KNOWN
GOOD KEY.
USING THE DRB,
PROGRAM THE KNOWN
GOOD IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
USING THE DRB,
CLEAR CODES.
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
S
Y
S
T
E
M
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE THE SKIM
MODULE.*
*Perform Verification TEST VER-1A.
I
M
M
O
B
I
L
I
Z
E
R
**Check connectors - Clean / repair as necessary.
333
S
E
N
T
R
Y
TEST SK-8A
REPAIRING - TRANSPONDER RESPONSE MISMATCH
Perform TEST SK-1A Before Proceeding
TJ BODY
XJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
FIG. 1
334
TEST SK-8A
S
E
N
T
R
Y
REPAIRING - TRANSPONDER RESPONSE MISMATCH
Perform TEST SK-1A Before Proceeding
START TEST
SK-8A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-8A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG. 1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
335
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-8A
CONTINUED - REPAIRING - TRANSPONDER RESPONSE MISMATCH
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
336
TEST SK-8A
CONTINUED - REPAIRING - TRANSPONDER RESPONSE MISMATCH
TEST SK-8A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
CLEAR CODES.
USING THE DRB,
ATTEMPT TO REPROGRAM
THE IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE IGNITION
KEY WITH A KNOWN
GOOD KEY.
USING THE DRB,
PROGRAM THE KNOWN
GOOD IGNITION KEY TO
THE SKIM MODULE.
SEE GENERAL INFO 8.0
USING THE DRB,
CLEAR CODES.
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON
AND CHECK CODES.
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
DOES THIS CODE
SET?
NO
TEST COMPLETE.*
YES
REPLACE THE SKIM
MODULE.*
*Perform Verification TEST VER-1A.
S
E
N
T
R
Y
**Check connectors - Clean / repair as necessary.
337
S
E
N
T
R
Y
TEST SK-9A
REPAIRING - VIN MISMATCH
Perform TEST SK-1A Before Proceeding
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
XJ BODY
S
Y
S
T
E
M
FIG. 1
338
TEST SK-9A
S
E
N
T
R
Y
REPAIRING - VIN MISMATCH
Perform TEST SK-1A Before Proceeding
START TEST
SK-9A.
USING THE DRB,
ERASE CODES.
K
E
Y
TURN IGNITION OFF.
WAIT 10 SECONDS.
TURN IGNITION ON.
USING THE DRB,
READ CODES.
DOES THE DRB
DISPLAY THIS CODE?
YES
CONTINUE TEST
SK-9A ON THE
NEXT PAGE.
YES
REPAIR AS
NECESSARY.*
NO
AT THIS TIME THE
CONDITION REQUIRED
TO SET THE CODE IS
NOT PRESENT.
FIG.1
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
S
Y
S
T
E
M
NO
REFER TO GENERAL
INFORMATION 3.3.2
FOR ADDITIONAL
INFORMATION ON
INTERMITTENT CODES.
*Perform Verification TEST VER-1A.
TEST COMPLETE.*
**Check connectors - Clean / repair as necessary.
339
I
M
M
O
B
I
L
I
Z
E
R
S
E
N
T
R
Y
TEST SK-9A
CONTINUED - REPAIRING - VIN MISMATCH
TJ BODY
K
E
Y
I
M
M
O
B
I
L
I
Z
E
R
S
Y
S
T
E
M
XJ BODY
340
TEST SK-9A
S
E
N
T
R
Y
CONTINUED - REPAIRING - VIN MISMATCH
TEST SK-9A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING THE DRB,
SELECT "ENGINE"
SYSTEM FROM THE
MAIN MENU.
TURN IGNITION ON.
K
E
Y
DISPLAY AND RECORD
THE VEHICLE
IDENTIFICATION
NUMBER (VIN).
DOES THE VIN
RECORDED FROM THE
PCM MATCH THE VIN
OF THE VEHICLE?
YES
REPLACE THE SKIM
MODULE.*
NO
REPROGRAM THE
CORRECT VIN INTO
THE PCM.
NOTE: THE VIN
CANNOT BE
PROGRAMMED INTO
THE SKIM MODULE.
S
Y
S
T
E
M
USING THE DRB,
DISPLAY AND RECORD
THE VIN THAT IS
PROGRAMMED INTO
THE SKIM MODULE.
DOES THE VIN
RECORDED FROM THE
SKIM MODULE MATCH
THE VIN OF THE
VEHICLE?
NO
REPLACE THE SKIM
MODULE.*
YES
TEST COMPLETE.*
*Perform Verification TEST VER-1A.
I
M
M
O
B
I
L
I
Z
E
R
**Check connectors - Clean / repair as necessary.
341
N TEST NTC-1A
O
NO TROUBLE CODE TEST MENU
Perform TEST DTC Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
NOTE: For all component locations, REFER TO GENERAL INFORMATION SECTION 4.0 in this
manual.
First, check all Technical Service Bulletins that relate to this problem. Perform corrective actions if
indicated, otherwise continue.
Second, read Diagnostics Trouble Codes, and repair any Diagnostic Trouble codes before
continuing.
1. No Trouble Code Complete Test (non-monitored circuits and monitored circuits). Perform
Tests NTC-2A through NTC-19A in sequence for Driveability problem.
2. No Trouble Code Quick Individual Test. If you suspect a symptom is directly related to a
component or system perform the associated NTC-Test(s) individually. Symptom check cannot
be used properly unless the Driveability problem actually happens while the vehicle is being
tested. Review of the appropriate General Information sections is essential before attempting
to diagnose any symptom. Return to No Trouble Code Menu if driveability problem still exists,
or perform No Trouble Code Complete Test.
3. No Trouble Code Tests NTC-20A through NTC-27A are intended to be performed according
to the component or system malfunction.
NO TROUBLE CODE MENU
CHECKING SECONDARY IGNITION AND TIMING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-2A
CHECKING THE PCM POWER AND GROUND CIRCUITS . . . . . . . . . . . . . . . . . . . . . . . . .NTC-3A
CHECKING THE ENGINE VACUUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-4A
CHECKING THE FUEL DELIVERY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-5A
CHECKING THE COOLANT SENSOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-6A
CHECKING THE THROTTLE POSITION SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-7A
CHECKING THE MAP SENSOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-8A
CHECKING THE OXYGEN SENSOR SWITCHING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-10A
CHECKING THE OXYGEN SENSOR HEATER . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-11A
CHECKING THE IDLE AIR CONTROL MOTOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-12A
CHECKING ENGINE MECHANICAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-13A
CHECKING THE BATTERY TEMP SENSOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-15A
CHECKING THE EVAPORATIVE EMISSION SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-17A
CHECKING THE INTAKE AIR TEMP SENSOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-19A
CHECKING THE PARK/NEUTRAL POSITION SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-20A
CHECKING THE OIL PRESSURE SENDING UNIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-21A
CHECKING THE FUEL LEVEL SENSOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-25A
CHECKING THE A/C SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-26A
CHECKING THE RADIATOR FAN OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NTC-27A
342
TEST NTC-1A
NO TROUBLE CODE TEST MENU
Perform TEST DTC Before Proceeding
SYMPTOM
DIAGNOSTIC TEST ROUTINE
HARD START
NTC-4A, 5A, 6A, 7A, 8A, 9A, 10A, 12A, 13A, 17A,
18A, 19A
START AND STALL
NTC-3A, 5A, 6A, 7A, 8A, 9A, 12A
HESITATION/SAG/STUMBLE
NO TROUBLE CODE COMPLETE TEST (STEP 1)
SURGE
NTC-3A, 5A, 6A, 7A, 8A, 9A, 10A, 12A, 17A
LACK OF POWER/SLUGGISH
NTC-3A, 5A, 6A, 7A, 8A, 9A, 10A, 12A, 18A
SPARK KNOCK/
DETONATION
NTC-3A, 5A, 6A, 7A, 8A, 9A, 10A, 12A, 17A
CUT OUTS/MISSES
NTC-3A, 5A, 9A, 10A, 18A
BACKFIRE/POPBACK
NTC-3A, 5A, 8A, 9A, 10A, 18A
RUNS ROUGH/UNSTABLE/
ERRATIC IDLE
NO TROUBLE CODE COMPLETE TEST
(STEP 1)
POOR FUEL ECONOMY
NO TROUBLE CODE COMPLETE TEST
(STEP 1)
343
N
O
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
N TEST NTC-2A
O
CHECKING SECONDARY IGNITION AND TIMING
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
2.5L
C
O
D
E
T
E
S
T
S
FIG. 1
4.0L
FIG. 2
344
TEST NTC-2A
N
O
CHECKING SECONDARY IGNITION AND TIMING
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-2A.
CONNECT A SUITABLE
ENGINE ANALYZER TO
THE ENGINE.
T
R
O
U
B
L
E
KEY OFF.
NOTE: IF THE
ENGINE WILL NOT
IDLE, MAINTAIN A
CONSTANT RPM ABOVE
IDLE.
ALLOW THE ENGINE
TO IDLE.
NOTE: SET THE
SCOPE TO READ
DISPLAY OR PARADE
PATTERN.
C
O
D
E
T
E
S
T
S
FOLLOW THE EQUIPMENT
MANUFACTURER’S
PROCEDURE FOR
PATTERN ANALYSIS.
FIG. 1 OR 2
IS THE SECONDARY
IGNITION PATTERN
OK?
NO
REPAIR THE
INDICATED
COMPONENT IN THE
SECONDARY IGNITION
SYSTEM.*
YES
REMOVE ANY SPARK
PLUG WIRE.
IS THE OPEN
CIRCUIT SECONDARY
VOLTAGE AT LEAST
25KV?
OBSERVE THE
SECONDARY KV LINE.
NO
REPLACE THE
ELECTRONIC
IGNITION COIL.*
YES
SECONDARY
IGNITION AND
TIMING ADV
NORMAL.
TEST PASSED.
REINSTALL THE
SPARK PLUG WIRE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
345
N TEST NTC-3A
O
CHECKING - THE PCM POWER AND GROUND CIRCUITS
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ BODY
XJ BODY
TJ BODY
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
346
TEST NTC-3A
N
O
CHECKING - THE PCM POWER AND GROUND CIRCUITS
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-3A.
T
R
O
U
B
L
E
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USING AN OHMMETER,
PROBE CAVITY A31
AT THE PCM
CONNECTOR.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
C
O
D
E
NO
T
E
S
T
S
YES
WITH AN OHMMETER,
PROBE CAVITY A32
AT THE PCM
CONNECTOR.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE GROUND
CIRCUIT FOR AN
OPEN.*
NO
REPAIR THE FUSED
B(+) CIRCUIT FOR
AN OPEN.*
YES
USING A VOLTMETER,
MEASURE CAVITY A22
AT THE PCM
CONNECTOR.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
YES
KEY ON.
USING A VOLTMETER,
MEASURE CAVITY A2
AT THE PCM
CONNECTOR.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUSED
IGNITION SWITCH
OUTPUT CIRCUIT FOR
AN OPEN.*
YES
PCM POWER AND
GROUND CIRCUITS
ARE NORMAL.
RECONNECT THE
POWERTRAIN CONTROL
MODULE CONNECTOR.
TEST PASSED.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
347
N TEST NTC-4A
O
CHECKING THE ENGINE VACUUM
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
348
TEST NTC-4A
N
O
CHECKING THE ENGINE VACUUM
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-4A.
ALLOW THE ENGINE
TO IDLE.
T
R
O
U
B
L
E
CONNECT A VACUUM
GAUGE TO THE
ENGINE.
C
O
D
E
NOTE: THE NORMAL
VACUUM READING WILL
VARY ACCORDING TO
THE ALTITUDE.
FIG. 1
T
E
S
T
S
OBSERVE THE VACUUM
GAUGE READING AT
IDLE.
IS THE VACUUM
GAUGE READING
BETWEEN 13" AND
22" STEADY?
NO
PERFORM TEST
NTC-13A.
FIG. 1
YES
ENGINE VACUUM
NORMAL.
TEST PASSED.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
349
N TEST NTC-5A
O
CHECKING THE FUEL DELIVERY
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
350
TEST NTC-5A
N
O
CHECKING THE FUEL DELIVERY
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-5A.
RELIEVE FUEL
PRESSURE.
T
R
O
U
B
L
E
WARNING: THE FUEL
SYSTEM MUST BE
OPENED AND MAY BE
UNDER HIGH
PRESSURE.
C
O
D
E
CONNECT A FUEL
PRESSURE GAUGE TO
FUEL SYSTEM.
SEE GENERAL INFO 9.0
IGNITION KEY ON.
IS THE FUEL
PRESSURE
339kPa +/- 34 kPa
(49.2 +/- 5 PSI)?
WITH THE DRB,
ACTUATE THE FUEL
SYSTEM TEST.
YES
FUEL PRESSURE
IS NORMAL
TEST PASSED.
NO
RECORD THE FUEL
PRESSURE READING.
IS THE FUEL
PRESSURE ABOVE
54.2 PSI?
YES
PERFORM SERVICE
MANUAL FUEL SYSTEM
PRESSURE CHECK
SECTION 14 BEFORE
CONTINUING.
NO
USING THE DRB,
STOP THE FUEL
SYSTEM ACTUATION
TEST.
IGNITION KEY OFF.
INSPECT THE FUEL
LINES FOR KINKED
OR RESTRICTED
LINES.
ARE THERE ANY
KINKED OR
RESTRICTED LINES?
RELIEVE FUEL
YES PRESSURE AND REPAIR
AS NECESSARY.*
SEE GENERAL INFO 9.0
NO
PERFORM SERVICE
MANUAL FUEL SYSTEM
PRESSURE CHECK
SECTION 14 BEFORE
CONTINUING.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
351
T
E
S
T
S
N TEST NTC-6A
O
CHECKING THE COOLANT SENSOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
352
TEST NTC-6A
N
O
CHECKING THE COOLANT SENSOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-6A.
START THE ENGINE.
USING THE DRB,
READ THE ENGINE
COOLANT
TEMPERATURE SENSOR
VALUE.
KEY ON.
WHILE MONITORING
DRB, ALLOW ENGINE TO
REACH NORMAL
OPERATING TEMP 820C
1800F OR ABOVE.
WAS THE COOLANT
TEMPERATURE VALUE
INCREASE A SMOOTH
TRANSITION?
NOTE: IF VEHICLE
0
TEMP
IS ABOVE 82 C
0
(180 F, ALLOW ENGINE
TO COOL UNTIL 640C
(150oF) IS REACHED.
NO
NOTE: INSPECT FOR
MECHANICAL COOLING
PROBLEMS BEFORE
REPLACING THE
SENSOR.
YES
REPLACE THE ECT
SENSOR.*
DID THE COOLANT
TEMPERATURE REACH
820C (1800F) OR
ABOVE?
NO
NOTE: INSPECT FOR
MECHANICAL COOLING
PROBLEMS BEFORE
REPLACING THE
SENSOR.
YES
REPLACE THE ECT
SENSOR.*
ECT SENSOR
OPERATING
NORMALLY
TEST PASSED.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
353
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
N TEST NTC-7A
O
CHECKING THE THROTTLE POSITION SENSOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
TJ/XJ BODY
FIG. 1
354
TEST NTC-7A
N
O
CHECKING THE THROTTLE POSITION SENSOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-7A.
T
R
O
U
B
L
E
DISCONNECT THE TP
SENSOR
CONNECTOR.**
KEY ON.
USING A VOLTMETER,
MEASURE THE TP
SENSOR SIGNAL
CIRCUIT.
FIG. 1
IS THE VOLTAGE
ABOVE 4.5 VOLTS?
NO
REPAIR THE OPEN IN
THE TP SENSOR
SIGNAL CIRCIUT.*
YES
KEY OFF. RECONNECT
THE TP SENSOR
HARNESS CONNECTOR.
KEY ON. USING THE
DRB, READ TP SENSOR
VOLTAGE. THROTTLE
MUST BE AGAINST
THROTTLE STOP.
IS THE VOLTAGE .92
OR LESS WITH THE
THROTTLE CLOSED?
NO
REPLACE THE
THROTTLE POSITION
SENSOR.*
YES
WHILE MONITORING
THE DRB, SLOWLY
OPEN AND CLOSE THE
THROTTLE.
IS THE VOLTAGE
CHANGE SMOOTH?
NO
REPLACE THE
THROTTLE POSITION
SENSOR.*
YES
STOP MOVING
LINKAGE. WIGGLE
THROTTLE POSITION
SENSOR CONNECTOR
AND HARNESS.
WAS THERE ANY
CHANGE IN THROTTLE
POSITION SENSOR
VOLTAGE WHEN
WIGGLED?
MONITOR THE DRB
DISPLAY.
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE VOLTAGE
CHANGE.*
YES
REPAIR THE HARNESS
OR CONNECTOR THAT
CAUSED THE ENGINE
RPM TO CHANGE.*
YES
REPAIR AS
NECESSARY.*
NO
START ENGINE.
WIGGLE THROTTLE
POSITION SENSOR
CONNECTORS AND
HARNESS.
MONITOR ENGINE
RPM.
WAS THERE ANY
CHANGE IN ENGINE
RPM WHEN WIGGLED?
NO
USING THE
SCHEMATIC AS A
GUIDE, INSPECT THE
WIRING AND
CONNECTORS.
WERE ANY PROBLEMS
FOUND?
NO
TP SENSOR
OPERATING
NORMALLY.
TEST PASSED.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
355
C
O
D
E
T
E
S
T
S
N TEST NTC-8A
O
CHECKING THE MAP SENSOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
356
TEST NTC-8A
N
O
CHECKING THE MAP SENSOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-8A.
TEE IN A VACUUM
GAUGE TO A
MANIFOLD VACUUM
SOURCE.
T
R
O
U
B
L
E
KEY OFF.
C
O
D
E
START THE ENGINE.
T
E
S
T
S
ALLOW THE ENGINE
TO IDLE.
NOTE: IF ENGINE
WILL NOT IDLE,
MAINTAIN A
CONSTANT RPM ABOVE
IDLE.
IS THE READING
WITHIN 1" OF THE
TEED-IN VACUUM
GAUGE?
USING THE DRB,
READ THE MAP
SENSOR VACUUM.
YES
MAP SENSOR
OPERATING
NORMALLY.
TEST PASSED.
NO
NOTE: INSPECT
VACUUM SUPPLY FOR
CORRECT OPERATION
BEFORE REPLACE
SENSOR.
REPLACE THE MAP
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
357
N TEST NTC-10A
O
CHECKING THE OXYGEN SENSOR SWITCHING
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ BODY
C
O
D
E
T
E
S
T
S
XJ BODY
358
TEST NTC-10A
N
O
CHECKING THE OXYGEN SENSOR SWITCHING
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-10A.
NOTE: THE DOWNSTREAM
O2 SENSOR SHOULD
SWITCH SLOWER THAN
THE UPSTREAM O2
SENSOR.
T
R
O
U
B
L
E
NOTE: ENGINE MUST
BE RUNNING AND AT
NORMAL OPERATION
TEMPERATURE.
USING THE DRB,
READ THE 1/1 AND
1/2 O2 SENSOR
STATES.
ARE THE 1/1 AND
1/2 O2 SENSOR
STATES SWITCHING
NORMALLY?
YES
O2 SENSORS
OPERATING
NORMALLY.
TEST PASSED.
NO
IS THE 1/1 O2
SENSOR LOCKED
"LEAN"?
YES
PERFORM TEST
NTC-10B.
NO
TURN THE ENGINE
OFF.
ALLOW FUEL
PRESSURE TO
STABILIZE.
INSTALL A FUEL
PRESSURE GAUGE TO
THE FUEL LINE.
WITH THE DRB
ACTUATE THE ASD
FUEL SYSTEM TEST.
TURN IGNITION ON.
USING THE DRB, STOP
FUEL SYSTEM TEST.
MONITOR THE PRESSURE
GAUGE FOR 1 MINUTE.
IS THE FUEL
PRESSURE BELOW 10
PSI?
YES
IF FUEL PUMP AND
LINES ARE OK,
REPLACE LEAKING
INJECTOR(S) AS
NECESSARY.*
NO
INSPECT THE AIR
FILTER AND INLET
DUCTS FOR
RESTRICTION(S).
WERE THERE ANY
RESTRICTIONS?
YES
REPAIR OR REPLACE
THE AIR INLET
SYSTEM AS
NECESSARY.*
NO
PERFORM TEST
NTC-13A.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
359
C
O
D
E
T
E
S
T
S
N TEST NTC-10B
O
CHECKING THE OXYGEN SENSOR SWITCHING
Perform TEST NTC-10A Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ 1/1 O2
XJ 1/1 O2
FIG. 2
FIG. 3
TJ 1/2 O2
XJ 1/2 O2
FIG. 4
FIG. 5
360
TEST NTC-10B
N
O
CHECKING THE OXYGEN SENSOR SWITCHING
Perform TEST NTC-10A Before Proceeding
START TEST
NTC-10B.
INSPECT THE ENGINE
FOR ANY ABNORMAL
VACUUM CONDITIONS.
T
R
O
U
B
L
E
ALLOW THE ENGINE
TO IDLE.
NOTE: REFER TO
FIGURE 1 FOR
INDICATORS OF
POSSIBLE ENGINE
MECHANICAL PROBLEMS.
ARE THERE ANY
ABNORMAL VACUUM
CONDITIONS?
YES
REPAIR ABNORMAL
ENGINE VACUUM
CONDITION AS
REQUIRED.*
NO
IS THE VOLTAGE
BELOW 0.10 VOLTS
FOR THE 1/1 OR 1/2
02 SENSOR?
WITH THE DRB, READ
THE 1/1 AND 1/2 O2
SENSOR VOLTAGES.
NO
CONTINUE TEST
NTC-10B ON THE
NEXT PAGE.
YES
KEY OFF.
DISCONNECT THE 1/1
OR 1/2 O2 SENSOR
CONNECTOR THAT THE
VOLTAGE IS BELOW
0.10 VOLTS.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE BETWEEN
THE O2 SENSOR...
SIGNAL CIRCUIT AND
GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE OXYGEN
SENSOR SIGNAL CKT
FOR A SHORT TO
GROUND.*
FIG. 2,3,4 OR 5
NO
REPLACE THE 1/1 OR
1/2 O2 SENSOR THAT
WAS BELOW 0.10
VOLTS.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
361
C
O
D
E
T
E
S
T
S
N TEST NTC-10B
O
T
R
O
U
B
L
E
CONTINUED - CHECKING THE OXYGEN SENSOR SWITCHING
TJ BODY
C
O
D
E
T
E
S
T
S
XJ BODY
362
TEST NTC-10B
N
O
CONTINUED - CHECKING THE OXYGEN SENSOR SWITCHING
TEST NTC-10B
CONTINUED FROM
THE PREVIOUS
PAGE.
WITH THE DRB IN
MISCELLANEOUS,
RESET THE ADAPTIVE
FUEL MEMORY.
T
R
O
U
B
L
E
KEY ON, ENGINE
OFF.
START ENGINE AND
LET IDLE FOR AT
LEAST THREE
MINUTES.
C
O
D
E
NOTE: ENGINE MUST
BE RUNNING AND AT
NORMAL OPERATING
TEMPERATURE.
T
E
S
T
S
NOTE: THE 1/2 O2
SENSOR SHOULD
SWITCH SLOWER THAN
THE 1/1 O2 SENSOR.
USING THE DRB,
READ THE O2 SENSOR
VOLTAGES.
ARE THE O2 SENSOR
VOLTAGES SWITCHING
NORMALLY?
YES
TEST PASSED.
NO
PERFORM TEST
NTC-13A.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
363
N TEST NTC-11A
O
CHECKING THE OXYGEN SENSOR HEATER
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ BODY
XJ BODY
TJ 1/1 O2
XJ 1/1 O2
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
TJ 1/2 O2
XJ 1/2 O2
FIG. 3
FIG. 4
364
TEST NTC-11A
N
O
CHECKING THE OXYGEN SENSOR HEATER
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-11A.
WAIT TWO MINUTES
FOR THE O2 SENSOR
VOLTAGES TO
STABILIZE.
KEY ON. USING THE
DRB, ACTUATE THE
O2 SENSOR HEATER
TEST.
T
R
O
U
B
L
E
NOTE: USE THE
APPROPRIATE O2
SENSOR CONNECTOR
WHEN USING THIS
TEST. (1/1 OR 1/2)
USING THE DRB,
READ THE 1/1 AND
1/2 O2 SENSOR
VOLTAGES.
IS THE VOLTAGE FOR
EITHER OF THE O2
SENSORS ABOVE
1.0 VOLT?
NO
STOP THE
ACTUATION TEST.
O2 SENSOR HEATERS
OK AT THIS TIME.
TEST PASSED.
T
E
S
T
S
YES
NOTE: THE O2 SENSOR
VOLTAGE STAYING
ABOVE 1.0 VOLT
INDICATES A PROBLEM
WITH THAT SENSOR.
NOTE: THE DRB IS
STILL ACTUATING
THE O2 SENSOR
HEATER TEST.
DISCONNECT THE O2
SENSOR CONNECTOR
THAT HAS VOLTAGE
ABOVE 1.0 VOLT.**
USING A VOLTMETER
MEASURE THE ASD
RELAY OUTPUT CIRCUIT
AT SENSOR CONNECTOR.
FIG. 1,2,3 OR 4
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE ASD
RELAY OUTPUT
CIRCUIT TO THE O2
SENSOR CONNECTOR
FOR AN OPEN.*
YES
USING THE DRB,
STOP THE ACTUATOR
TEST.
USING AN OHMMETER
MEASURE THE
RESISTANCE BETWEEN
THE HEATER
GROUND...
CIRCUIT AND
GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE HEATER
GROUND CIRCUIT FOR
AN OPEN.*
FIG. 1,2,3 OR 4
YES
REPLACE THE O2
SENSOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
365
C
O
D
E
N TEST NTC-12A
O
CHECKING THE IDLE AIR CONTROL MOTOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
366
TEST NTC-12A
N
O
CHECKING THE IDLE AIR CONTROL MOTOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-12A.
WITH THE DRB IN
ACTUATOR TESTS,
SET ENGINE SPEED
TO 1400 RPM.
IS THE ENGINE
SPEED 1400 RPM
100 RPM?
YES
WITH THE DRB,
STOP ALL TESTS.
IAC MOTOR IS
OPERATING OK.
TEST PASSED.
T
R
O
U
B
L
E
REPAIR VACUUM
LEAK(S) AS
NECESSARY.*
C
O
D
E
NO
WITH THE DRB, STOP
ALL TESTS.
INSPECT THE ENGINE
FOR ANY VACUUM
LEAK(S).
IS THERE ANY
VACUUM LEAKS?
YES
NO
TURN KEY OFF.
DISCONNECT THE
IDLE AIR CONTROL
MOTOR CONNECTOR.**
DETERMINE IF AN
OPEN CIRCUIT
EXISTS BETWEEN...
T
E
S
T
S
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
IAC CONNECTOR
#1 DRIVER
&
PCM CONNECTOR
#1 DRIVER.
DOES AN
YES
REPAIR THE
OPEN CIRCUIT
OPEN CIRCUIT.
EXIST?
NO
DETERMINE IF AN
OPEN CIRCUIT
EXISTS BETWEEN...
IAC CONNECTOR
#2 DRIVER
&
PCM CONNECTOR
#2 DRIVER.
DOES AN
YES
REPAIR THE
OPEN CIRCUIT
OPEN CIRCUIT.
EXIST?
NO
DETERMINE IF AN
OPEN CIRCUIT
EXISTS BETWEEN...
IAC CONNECTOR
#3 DRIVER
&
PCM CONNECTOR
#3 DRIVER.
DOES AN
YES
REPAIR THE
OPEN CIRCUIT
OPEN CIRCUIT.
EXIST?
NO
DETERMINE IF AN
OPEN CIRCUIT
EXISTS BETWEEN...
IAC CONNECTOR
#4 DRIVER
&
PCM CONNECTOR
#4 DRIVER.
DOES AN
YES
REPAIR THE
OPEN CIRCUIT
OPEN CIRCUIT.
EXIST?
NO
REPLACE THE IDLE
AIR CONTROL
MOTOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
367
N TEST NTC-13A
O
CHECKING THE ENGINE MECHANICAL
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
NOTES
C
O
D
E
T
E
S
T
S
368
TEST NTC-13A
CHECKING THE ENGINE MECHANICAL
Perform TEST NTC-1A Before Proceeding
The components and systems that you have checked before this are operating properly. Here are
additional non-monitored components or systems to check, that could cause a driveability problem.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
DISTRIBUTOR POSITION — must be within specifications
ENGINE VACUUM — must be at least 13 inches in neutral (see below) †
ENGINE VALVE TIMING — must be within specifications
ENGINE COMPRESSION — must be within specifications
ENGINE EXHAUST SYSTEM — must be free of any restrictions
ENGINE PCV SYSTEM — must flow freely
ENGINE DRIVE SPROCKET — must be properly positioned
TORQUE CONVERTER STALL SPEED — must be within specifications (auto only)
POWER BRAKE BOOSTER — no internal vacuum leaks
FUEL — must be free of contamination
FUEL INJECTOR — plugged or restricted injector; control wire not connected to correct
injector
NOTE: If you came to this test from the oxygen sensor, and the rich or lean condition is not caused
by one of the first items above, replace the powertrain control module and perform TEST
VER-2A (Road Test Verification)
Checking Distributor Position With DRBIIIT
§Connect the DRB to the data link connector and select SET SYNC from the menu. WARNING: The
following test will be performed with the engine running: avoid contact with rotating components.
Start the engine and observe the DRB display. When the distributor is correctly positioned, the IN
RANGE message should appear along with 0°. If the distributor needs to be adjusted, loosen the
distributor hold-down clamp bolt. Rotate the distributor until reading is as close to 0° as possible and
the IN RANGE message displayed. Tighten the clamp bolt to 22.5 N·m (200 in. lbs.) torque.
NOTE: Setting the distributor position does not adjust the ignition timing. Ignition timing valves are
determined by the powertrain control module:
† The readings below are only indicators of possible mechanical engine problems.
369
N
O
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
N TEST NTC-15A
O
CHECKING BATTERY TEMP SENSOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
370
TEST NTC-15A
N
O
CHECKING BATTERY TEMP SENSOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-15A
T
R
O
U
B
L
E
USING A TEMP PROBE,
READ AIR/BATT
TEMPERATURE NEAR THE
BATTERY TEMP SENSOR.
COMPARE
TEMPERATURE TO DRB
BATTERY TEMP
SENSOR READING.
IS THE TEMPERATURE
WITHIN -150C (50F)
OF EACH OTHER?
NO
REPLACE THE
BATTERY TEMP
SENSOR.*
T
E
S
T
S
YES
BATTERY TEMP
SENSOR, TEST
PASSED.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
371
C
O
D
E
N TEST NTC-17A
O
CHECKING THE EVAPORATIVE EMISSION SYSTEM
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
372
TEST NTC-17A
N
O
CHECKING THE EVAPORATIVE EMISSION SYSTEM
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-17A.
T
R
O
U
B
L
E
NOTE: CAREFULLY
INSPECT ALL VACUUM
HOSES FOR PROPER
ROUTING AND FOR
PINCHED OR...
PLUGGED HOSES FROM
THE ENGINE TO THE
EVAP SOLENOID TO
THE GAS TANK.
ARE ALL THE VACUUM
HOSES OK?
NO
REPAIR THE VACUUM
HOSES AS
NECESSARY.*
T
E
S
T
S
YES
START THE ENGINE AND
ALLOW IT TO REACH
NORMAL OPERATING
TEMPERATURE 760C
0
(170 F).
DISCONNECT THE
PURGE VACUUM HOSE
AT THE SOLENOID
THAT GOES TO THE
CANISTER.
TURN ENGINE OFF
(IGN. OFF).
START THE ENGINE.
THERE SHOULD BE NO
FLOW THROUGH THE
SOLENOID FOR 1 TO
2 MINUTES.
IS THE PURGE
SOLENOID ALLOWING
VACUUM THROUGH THE
SOLENOID WITHIN 1
MINUTE?
YES
CONTINUE TEST
NTC-17A ON THE
NEXT PAGE.
NO
AFTER 90 SECONDS,
THE PURGE
SOLENOID WILL
ALLOW VACUUM TO...
IS THE EVAP SOLENOID
ALLOWING VACUUM TO
CYCLE THROUGH
INTERMITTENTLY AT A
STEADY RATE?
CYCLE
INTERMITTENTLY AT
A STEADY RATE.
NO
REPLACE THE PURGE
SOLENOID.*
YES
NOTE: IN THE NEXT
STEPS, DO NOT USE
MORE THAN FIVE
PSI.
KEY OFF, ATTEMPT
TO BLOW AIR
THROUGH THE VACUUM
LINE THAT GOES TO
THE CANISTER.
DOES THE CANISTER
AND VACUUM LINE
ALLOW AIR TO PASS?
YES
PURGE SOLENOID
AND HOSES ARE
OK. TEST
PASSED.
NO
CONTINUE TEST
NTC-17B ON THE
NEXT PAGE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
373
C
O
D
E
N TEST NTC-17A
O
CONTINUED - CHECKING THE EVAPORATIVE EMISSION SYSTEM
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
374
TEST NTC-17A
CONTINUED - CHECKING THE EVAPORATIVE EMISSION SYSTEM
TEST NTC-17A
CONTINUED FROM
THE PREVIOUS
PAGE.
REMOVE THE PURGE
SOLENOID AND TAP
THE PORTS AGAINST
A CLEAN, SOLID
SURFACE.
DID ANY FOREIGN
MATERIAL FALL OUT?
NO
REPLACE THE EVAP
PURGE SOLENOID.*
YES
INSPECT LINE FROM
THE PURGE SOLENOID
TO THE CANISTER.
IS THE LINE
DISCONNECTED,
RIPPED OR CUT?
NO
CLEAN OUT THE LINE
AND REPLACE THE
EVAP PURGE
SOLENOID AND
CANISTER.*
YES
REPAIR THE LINE
AND REPLACE THE
PURGE SOLENOID.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
375
N
O
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
N TEST NTC-17B
O
CHECKING THE EVAPORATIVE EMISSION SYSTEM
Perform TEST NTC-17A Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
376
TEST NTC-17B
N
O
CHECKING THE EVAPORATIVE EMISSION SYSTEM
Perform TEST NTC-17A Before Proceeding
START TEST
NTC-17B.
T
R
O
U
B
L
E
DISCONNECT THE
VACUUM LINE AT THE
CANISTER THAT GOES
TO THE EVAP
SOLENOID.
ATTEMPT TO BLOW
AIR THROUGH THE
VACUUM LINE THAT
GOES TO THE
CANISTER.
DOES THE VACUUM
LINE ALLOW AIR TO
PASS?
YES
REPLACE THE
EVAPORATIVE
CANISTER.*
T
E
S
T
S
NO
REPAIR OR REPLACE
THE VACUUM LINE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
377
C
O
D
E
N TEST NTC-19A
O
CHECKING THE INTAKE AIR TEMPERATURE SENSOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
378
TEST NTC-19A
N
O
CHECKING THE INTAKE AIR TEMPERATURE SENSOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-19A
KEY OFF. REMOVE
THE IAT SENSOR.
FIG. 1 OR 2
NOTE: MAKE SURE
THE IGNITION KEY
IS ON AT THIS TIME
(ENGINE OFF).
NOTE: DO NOT ALLOW
MORE THAN 5
MINUTES DELAY
BETWWEN NEXT
STEPS.
USING A TEMP
PROBE, MEASURE THE
IAT INSIDE IAT
SENSOR OPENING.
FIG. 1 OR 2
IS THE IAT
RECORDING WITHIN
-120C (100F) OF
THE PROBE READING?
USING THE DRB, READ
THE INTAKE AIR
TEMPERATURE (IAT)
SENSOR AND RECORD
THE READING.
NO
REPLACE THE INTAKE
AIR TEMPERATURE
(IAT) SENSOR.*
RECONNECT THE
MAP SENSOR.
INTAKE AIR TEMP
(IAT) SENSOR
TEST PASSED.
**Check connectors - Clean / repair as necessary.
379
C
O
D
E
T
E
S
T
S
YES
*Perform Verification TEST VER-2A.
T
R
O
U
B
L
E
N TEST NTC-20A
O
CHECKING THE PARK/NEUTRAL POSITION SWITCH
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
XJ BODY 4.0L AUTO TRANS
C
O
D
E
T
E
S
T
S
XJ BODY 4.0L AUTO TRANS
FIG. 1
380
TEST NTC-20A
N
O
CHECKING THE PARK/NEUTRAL POSITION SWITCH
Perform TEST NTC-1A Before Proceeding
IS THIS VEHICLE
EQUIPPED WITH A 4
SPEED AISIN
TRANSMISSION?
START TEST
NTC-20A.
NO
PERFORM TEST
NTC-20B.
YES
WITH THE DRB, READ
THE PARK/NEUTRAL
SWITCH INPUT
STATE.
WHILE MOVING GEAR
SELECTOR THROUGH
ALL GEAR
POSITIONS, WATCH
THE DRB DISPLAY.
DID THE DRB DISPLAY
"P/N" AND "D/R"?
YES
TRANS RANGE
SENSOR.
TEST PASSED.
NO
DOES THE
PARK/NEUTRAL
SWITCH INPUT
DISPLAY P/N ONLY?
NO
CONTINUE TEST
NTC-20A ON THE
NEXT PAGE.
YES
REPLACE THE
TRANSMISSION RANGE
SENSOR.*
YES
DISCONNECT THE
TRANS RANGE SENSOR
HARNESS
CONNECTOR.**
MONITOR THE
PARK/NEUTRAL
SWITCH INPUT STATE
ON THE DRB.
DOES THE DRB
DISPLAY D/R?
NO
TURN THE IGNITION
OFF.
DISCONNECT THE THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE OF THE
P/N POSITION SW
SENSE CIRCUIT TO
GROUND. FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
P/N POSITION
SWITCH SENSE
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
381
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
N TEST NTC-20A
O
T
R
O
U
B
L
E
CONTINUED - CHECKING THE PARK/NEUTRAL POSITION SWITCH
XJ BODY 4.0L AUTO TRANS
C
O
D
E
T
E
S
T
S
FIG. 1
382
TEST NTC-20A
CONTINUED - CHECKING THE PARK/NEUTRAL POSITION SWITCH
TEST NTC-20A
CONTINUED FROM
THE PREVIOUS
PAGE.
T
R
O
U
B
L
E
KEY OFF.
DISCONNECT THE
TRANSMISSION RANGE
SENSOR HARNESS
CONNECTOR.**
KEY ON. USING A
VOLTMETER, MEASURE
THE THE P/N POSITION
SWITCH SENSE
CIRCUIT. FIG. 1
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN IN
THE P/N POSITION
SWITCH SENSE
CIRCUIT.*
USING A TEST LIGHT
CONNECTED TO
GROUND, PROBE THE
P/N POSITION SW
SENSE CKT. FIG.1
DOES THE TEST
LIGHT ILLUMINATE
BRIGHTLY?
YES
THE TEST LIGHT MAY
ILLUMINATE VERY
DIM, THIS SHOULD
BE CONSIDERED
NORMAL OPERATION.
NO
STOP ACTUATION.
USING THE DRB,
MONITOR THE
PARK/NEUTRAL SWITCH
INPUT STATE.
USING A JUMPER WIRE,
CONNECT ONE END TO
THE P/N POSITION
SWITCH SENSE CIRCUIT
AND...
REPAIR THE SHORT
TO VOLTAGE IN THE
P/N POSITION
SWITCH SENSE
CIRCUIT.*
THE OTHER END TO A
KNOWN GOOD GROUND.
DOES THE DISPLAY
ON THE DRB CHANGE
TO P/N?
FIG. 1
YES
REPLACE THE
TRANSMISSION RANGE
SENSOR.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
383
C
O
D
E
T
E
S
T
S
YES
USING THE DRB,
ACTUATE THE ASD
RELAY.
N
O
N TEST NTC-20B
O
CHECKING THE PARK/NEUTRAL POSITION SWITCH
Perform TEST NTC-21A Before Proceeding
T
R
O
U
B
L
E
TJ BODY 2.5L AND 4.0L AUTO TRANS
C
O
D
E
T
E
S
T
S
XJ BODY 2.5L AUTO TRANS
TJ/XJ 3 SPEED AUTO TRANS
FIG. 1
384
TEST NTC-20B
N
O
CHECKING THE PARK/NEUTRAL POSITION SWITCH
Perform TEST NTC-21A Before Proceeding
START TEST
NTC-20B.
T
R
O
U
B
L
E
WITH THE DRB, READ
THE PARK/NEUTRAL
SWITCH INPUT
STATE.
WHILE MOVING GEAR
SELECTOR THROUGH
ALL GEAR
POSITIONS, WATCH
THE DRB DISPLAY.
DID THE DRB DISPLAY
"P/N" AND "D/R"?
YES
PARK/NEUTRAL
POSITION
SWITCH.
TEST PASSED.
NO
DOES THE
PARK/NEUTRAL
SWITCH INPUT
DISPLAY P/N ONLY?
YES
CONTINUE TEST
NTC-20B ON THE
NEXT PAGE.
YES
REPLACE THE
TRANSMISSION RANGE
SENSOR.*
NO
DISCONNECT THE
TRANS RANGE SENSOR
HARNESS
CONNECTOR.**
MONITOR THE
PARK/NEUTRAL
SWITCH INPUT STATE
ON THE DRB.
DOES THE DRB
DISPLAY D/R?
NO
TURN THE IGNITION
OFF.
DISCONNECT THE THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE OF THE
P/N POSITION SW
SENSE CIRCUIT TO
GROUND. FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
P/N POSITION
SWITCH SENSE
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
385
C
O
D
E
T
E
S
T
S
N TEST NTC-20B
O
T
R
O
U
B
L
E
CONTINUED - CHECKING THE PARK/NEUTRAL POSITION SWITCH
TJ/XJ 3 SPEED AUTO TRANS
C
O
D
E
T
E
S
T
S
FIG. 1
386
TEST NTC-20B
CONTINUED - CHECKING THE PARK/NEUTRAL POSITION SWITCH
TEST NTC-20B
CONTINUED FROM
THE PREVIOUS
PAGE.
T
R
O
U
B
L
E
KEY OFF.
DISCONNECT THE P/N
POSITION SWITCH
HARNESS
CONNECTOR.**
KEY ON. USING A
VOLTMETER, MEASURE
THE THE P/N POSITION
SWITCH SENSE
CIRCUIT. FIG. 1
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN IN
THE P/N POSITION
SWITCH SENSE
CIRCUIT.*
USING A TEST LIGHT
CONNECTED TO
GROUND, PROBE THE
P/N POSITION SW
SENSE CKT. FIG.1
DOES THE TEST
LIGHT ILLUMINATE
BRIGHTLY?
NOTE: THE TEST LIGHT
YES MAY ILLUMINATE VERY
DIM, THIS SHOULD BE
CONSIDERED NORMAL
OPERATION.
NO
STOP ACTUATION.
USING THE DRB,
MONITOR THE
PARK/NEUTRAL SWITCH
INPUT STATE.
USING A JUMPER WIRE,
CONNECT ONE END TO
THE P/N POSITION
SWITCH SENSE CIRCUIT
AND...
REPAIR THE SHORT
TO VOLTAGE IN THE
P/N POSITION
SWITCH SENSE
CIRCUIT.*
THE OTHER END TO A
KNOWN GOOD GROUND.
DOES THE DISPLAY
ON THE DRB CHANGE
TO P/N?
FIG. 1
YES
REPLACE THE
PARK/NEUTRAL
POSITION SWITCH.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
387
C
O
D
E
T
E
S
T
S
YES
USING THE DRB,
ACTUATE THE ASD
RELAY.
N
O
N TEST NTC-21A
O
CHECKING THE OIL PRESSURE SENDING UNIT
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
TJ/XJ BODY
FIG. 3
388
TEST NTC-21A
N
O
CHECKING THE OIL PRESSURE SENDING UNIT
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-21A.
NOTE: THIS WILL
PUT THE CLUSTER IN
SELF TEST.
T
R
O
U
B
L
E
TURN IGN OFF. PUSH
AND HOLD THE TRIP
ODOMETER BUTTON
WHILE TURNING THE
IGN SW TO RUN.
OBSERVE THE OIL
PRESSURE GAUGE
DURING THE SELF
TEST.
FIG. 1
DID THE GAUGE
REACH ITS
CALIBRATION POINTS
(0,40 AND 80)?
NO
REPLACE THE
INSTRUMENT
CLUSTER.*
T
E
S
T
S
YES
KEY OFF,
DISCONNECT THE OIL
PRESSURE SENSOR
HARNESS
CONNECTOR.**
USING AN
VOLTMETER, MEASURE
THE OIL PRESSURE
SIGNAL CIRCUIT.
FIG. 2
IS THE VOLTAGE
ABOVE 4.0 VOLTS?
YES
CONTINUE TEST
NTC-21A ON NEXT
PAGE.
NO
KEY OFF.
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE SIGNAL
CKT FROM THE PCM
TO THE SENSOR.
FIG. 3
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
OIL PRESSURE
SIGNAL CIRCUIT.*
YES
USING AN OHMMETER,
MEASURE THE OIL
PRESSURE SIGNAL
CKT TO GROUND.
FIG. 3
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE SHORT
TO GROUND IN THE
OIL PRESSURE
SIGNAL CIRCUIT.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
389
C
O
D
E
N TEST NTC-21A
O
T
R
O
U
B
L
E
CONTINUED - CHECKING OIL PRESSURE SENDING UNIT
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
390
TEST NTC-21A
N
O
CONTINUED - CHECKING OIL PRESSURE SENDING UNIT
TEST NTC-21A
CONTINUED FROM
PREVIOUS PAGE.
USING AN OHMMETER,
MEASURE THE SENSOR
GROUND CKT TO
GROUND. FIG. 1
IS THE RESISANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE SENSOR GROUND
CIRCUIT.*
YES
USING A VOLTMETER,
MEASURE THE 5-VOLT
SUPPLY CIRCUIT.
IS THE VOLT ABOVE
4.0 VOLTS?
YES
CONTINUE TEST
NTC-21A ON THE
NEXT PAGE.
T
R
O
U
B
L
E
C
O
D
E
FIG. 1
T
E
S
T
S
NO
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
5-VOLT SUPPLY CKT.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE 5-VOLT SUPPLY
CIRCUIT.*
YES
REPAIR THE SHORT
TO GROUND IN THE
5-VOLT SUPPLY.**
YES
USING AN OHMMETER,
MEASURE THE 5-VOLT
SUPPLY CKT TO
GROUND.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
391
N TEST NTC-21A
O
T
R
O
U
B
L
E
CONTINUED - CHECKING OIL PRESSURE SENDING UNIT
NOTES
C
O
D
E
T
E
S
T
S
392
TEST NTC-21A
N
O
CONTINUED - CHECKING OIL PRESSURE SENDING UNIT
TEST NTC-21A
CONTINUED FROM
PREVIOUS PAGE.
FOLLOW THE SERVICE
MANUAL SECTION 9.0
FOR OIL PRESSURE
DIAGNOSIS.
IS THE OIL
PRESSURE WITHIN
THE SERVICE MANUAL
SPECIFICATIONS?
NO
REPAIR THE OIL
PRESSURE PROBLEM
PER THE SERVICE
MANUAL.*
T
R
O
U
B
L
E
YES
REPLACE THE OIL
PRESSURE SENSOR.*
C
O
D
E
T
E
S
T
S
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
393
N TEST NTC-25A
O
CHECKING THE FUEL LEVEL SENSOR
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ BODY
XJ BODY
TJ BODY
XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
FIG. 2
394
TEST NTC-25A
N
O
CHECKING THE FUEL LEVEL SENSOR
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-25A.
T
R
O
U
B
L
E
DISCONNECT THE
FUEL PUMP MODULE
HARNESS
CONNECTOR.**
USING THE DRB,
READ THE FUEL
LEVEL SENSOR
VOLTAGE.
IS THE FUEL LEVEL
SENSOR VOLTAGE
ABOVE 9.9 VOLTS?
NO
REPAIR THE FUEL
LEVEL SENSOR
SIGNAL CIRCUIT FOR
RESISTANCE TO
GROUND.*
T
E
S
T
S
YES
USING A JUMPER
WIRE, JUMPER THE
FUEL LEVEL SENSOR
SIGNAL CIRCUIT TO
THE...
SENSOR GROUND
CIRCUIT AT THE FUEL
PUMP CONNECTOR.
FIG. 1 OR 2
USING THE DRB,
READ FUEL LEVEL
SENSOR VOLTAGE.
IS THE FUEL LEVEL
SENSOR VOLTAGE
ABOVE 0.09 VOLTS?
NO
REPLACE THE FUEL
LEVEL SENDING
UNIT.*
NO
REPAIR THE OPEN IN
THE SENSOR GROUND
CIRCUIT.*
YES
USING A JUMPER
WIRE, JUMPER THE
FUEL LEVEL SENSOR
SIGNAL CIRCUIT...
TO A GOOD GROUND.
IS THE FUEL LEVEL
SENSOR VOLTAGE
ABOVE 0.09 VOLTS?
FIG. 1 OR 2
YES
REPAIR THE OPEN IN
THE FUEL LEVEL
SENSOR SIGNAL CKT.
IF OK, REPLACE
PCM.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
395
C
O
D
E
N TEST NTC-26A
O
CHECKING THE A/C SYSTEM
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
TJ/XJ BODY
C
O
D
E
T
E
S
T
S
FIG. 1
TJ BODY
FIG. 2
XJ BODY
FIG. 3
396
TEST NTC-26A
N
O
CHECKING THE A/C SYSTEM
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-26A.
IS THERE AN A/C
CLUTCH RELAY FAULT
CODE?
YES
PERFORM TEST
TC-16A.
NO
VERIFY THAT THE
REFRIGERANT SYSTEM
IS PROPERLY CHARGED,
PER SERVICE MANUAL
SECTION 24.
IS THE REFRIGERANT
SYSTEM PROPERLY
CHARGED?
NO
PROPERLY CHARGE
THE REFRIGERANT
SYSTEM PER THE
SERVICE MANUAL
SECTION 24.
YES
USING THE DRB,
ACTUATE THE A/C
CLUTCH RELAY.
DID THE A/C CLUTCH
ACTUATE?
YES
THE A/C CLUTCH
CHECKS OK AT
THIS TIME.
YES
REPLACE THE CLUTCH
COIL.*
NO
DISCONNECT THE A/C
CLUTCH CONNECTOR.
WITH A VOLTMETER,
MEASURE THE A/C...
FIG. 1
CLUTCH RELAY
OUTPUT AT THE A/C
CLUTCH CONN. NOTE:
ACTUATION SHOULD
STILL BE RUNNING.
DOES THE VOLTAGE
SWITCH FROM 0 TO
12 VOLTS?
NO
REMOVE THE A/C
CLUTCH RELAY. WITH A
VOLTMETER, MEASURE
FUSED B(+) AT THE
RELAY. FIG. 2 OR 3
IS THE VOLTAGE
ABOVE 11.0 VOLTS?
NO
REPAIR THE OPEN
FUSED B(+)
CIRCUIT.*
NO
REPAIR THE OPEN
A/C CLUTCH RELAY
OUTPUT CIRCUIT.*
YES
WITH AN OHMMETER,
MEASURE THE A/C
CLUTCH RELAY
OUTPUT FROM THE
RELAY...
TO THE A/C
CLUTCH COIL
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE A/C
CLUTCH RELAY.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
397
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
N TEST NTC-27A
O
CHECKING THE RADIATOR FAN OPERATION
Perform TEST NTC-1A Before Proceeding
T
R
O
U
B
L
E
XJ BODY
C
O
D
E
T
E
S
T
S
XJ BODY
FIG. 1
XJ BODY
FIG. 2
398
TEST NTC-27A
N
O
CHECKING THE RADIATOR FAN OPERATION
Perform TEST NTC-1A Before Proceeding
START TEST
NTC-27A.
IS THERE A RAD FAN
RELAY FAULT CODE
PRESENT?
YES
REPAIR THE RAD FAN
RELAY FAULT
CODES.*
NO
USING THE DRB,
ACTUATE THE RAD
FAN RELAY.
DID THE RAD FAN
ACTUATE?
YES
THE RAD FAN
CHECKS OK AT
THIS TIME.*
KEY ON.
ACTUATE THE RAD FAN.
USING A VOLTMETER,
MEASURE THE RAD FAN
RELAY OUTPUT AT THE
FAN. FIG. 1
DOES THE VOLTAGE
CYCLE FROM 0 TO12
VOLTS?
YES
CONTINUE TEST
NTC-27A ON THE
NEXT PAGE.
NO
KEY OFF, REMOVE
THE RADIATOR FAN
RELAY.**
KEY ON. USING A
VOLTMETER, MEASURE
THE FUSED IGNITION
SWITCH OUTPUT CKT AT
THE RELAY. FIG. 2
IS THE VOLTAGE
ABOVE 11.0 VOLTS?
NO
REPAIR THE OPEN
FUSED IGNITION
SWITCH OUTPUT
CIRCUIT.*
YES
USING AN OHMMETER,
MEASURE THE RAD
FAN RELAY OUTPUT
FROM THE RELAY...
TO THE RAD FAN
MOTOR.
IS RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
RADIATOR FAN RELAY
OUTPUT CIRCUIT.*
FIG. 1 AND 2
YES
REPLACE THE
RADIATOR FAN
RELAY.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
399
C
O
D
E
T
E
S
T
S
NO
KEY OFF, REMOVE THE
RADIATOR FAN HARNESS
CONNECTOR.**
T
R
O
U
B
L
E
N TEST NTC-27A
O
CONTINUED - CHECKING THE RADIATOR FAN OPERATION
T
R
O
U
B
L
E
C
O
D
E
T
E
S
T
S
FIG. 1
400
TEST NTC-27A
N
O
CONTINUED - CHECKING THE RADIATOR FAN OPERATION
TEST NTC-27A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING AN OHMMETER,
MEASURE THE RAD
FAN GROUND CIRCUIT
TO A GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
RADIATOR FAN
GROUND CIRCUIT.*
YES
C
O
D
E
REPLACE THE
RADIATOR FAN
MOTOR.*
*Perform Verification TEST VER-2A.
**Check connectors - Clean / repair as necessary.
401
T
R
O
U
B
L
E
T
E
S
T
S
S
P
E
E
D
TEST SC-1A
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST DTC Before Proceeding
TJ/XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
402
TEST SC-1A
S
P
E
E
D
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST DTC Before Proceeding
START TEST
SC-1A.
NOTE: USE THIS
TEST ONLY WHEN
THERE ARE NO SPEED
CONTROL CODES SET.
USING A DRB,
ACTUATE THE S/C
VACUUM SOLENOID.
IS THE S/C VACUUM
SOLENOID CLICKING?
NO
PERFORM TEST
TC-1B
YES
STOP THE S/C
VACUUM SOLENOID
ACTUATION.
USING THE DRB
ACTUATE THE S/C
VENT SOLENOID.
IS THE S/C VENT
SOLENOID CLICKING?
NO
PERFORM TEST
TC-1B
NO
PERFORM TEST
SC-2A.
NO
REPLACE THE SET
SWITCH.*
YES
KEY ON, WITH THE
DRB, MONITOR THE
SPEED CONTROL
SWITCH INPUTS.
WHILE OBSERVING
DISPLAY, PRESS THE
SPEED CONTROL "ON"
SWITCH.
DOES THE DRB
DISPLAY SPEED
CONTROL SWITCH
"ON"?
YES
WHILE OBSERVING
THE DISPLAY, PRESS
THE SET SWITCH
SEVERAL TIMES.
DOES THE DRB
DISPLAY SET SWITCH
"PRESSED" OR
"RELEASED"?
YES
WHILE OBSERVING
THE DISPLAY, PRESS
THE RESUME SWITCH
SEVERAL TIMES.
DOES THE DRB
DISPLAY RESUME
SWITCH "PRESSED"
OR "RELEASED"?
NO
PERFORM TEST
SC-3A.
NO
REPLACE THE CANCEL
SWITCH.*
YES
WHILE OBSERVING
THE DISPLAY, PRESS
THE CANCEL SWITCH
SEVERAL TIMES.
DOES THE DRB
DISPLAY CANCEL
SWITCH "PRESSED"
OR "RELEASED"?
YES
PERFORM TEST
SC-4A.
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
403
C
O
N
T
R
O
L
T
E
S
T
S
S
P
E
E
D
TEST SC-1B
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST SC-1A Before Proceeding
C
O
N
T
R
O
L
T
E
S
T
S
FIG. 1
404
TEST SC-1B
S
P
E
E
D
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST SC-1A Before Proceeding
START TEST
SC-1B.
KEY OFF,
DISCONNECT THE
SPEED CONTROL
SERVO CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
NO
USING AN OHMMETER,
MEASURE RESISTANCE
OF THE GROUND
CIRCUIT TO GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
GROUND CIRCUIT.*
YES
IGNITION ON. WITH
THE DRB, ACTUATE
THE S/C VENT
SOLENOID.
USING A VOLTMETER
MEASURE THE S/C
BRAKE SWITCH OUTPUT
CKT AT S/C
CONNECTOR.
FIG. 1
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
PERFORM TEST
SC-1D.
YES
PERFORM TEST
SC-5A.
YES
RECONNECT THE SPEED
CONTROL SERVO
CONNECTOR. START
ENGINE, ALLOW TO
IDLE 1 MINUTE.
TURN ENGINE OFF
(IGNITION ON). WITH
THE DRB, ACTUATE THE
SPEED CONTROL SERVO
SOLENOIDS.
DOES THE THROTTLE
OPEN AND CLOSE?
NO
KEY OFF,
DISCONNECT THE
VACUUM SUPPLY TO
THE SPEED CONTROL
SERVO.
ATTACH A VACUUM
GAUGE TO THE
DISCONNECTED HOSE.
START ENGINE.
DOES THE VACUUM
GAUGE READ
MANIFOLD VACUUM?
NO
REPAIR THE VACUUM
SUPPLY FOR A LEAK
OR RESTRICTION.*
NO
REPLACE THE VACUUM
RESERVOIR.*
YES
TURN ENGINE OFF,
OBSERVE THE VACUUM
GAUGE FOR 10
SECONDS.
DOES THE VACUUM
HOLD FOR AT LEAST
10.0 SECONDS?
YES
PERFORM TEST
SC-1C.
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
405
C
O
N
T
R
O
L
T
E
S
T
S
S
P
E
E
D
TEST SC-1C
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST SC-1A Before Proceeding
TJ/XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
FIG. 1
TJ/XJ BODY
FIG. 2
406
TEST SC-1C
S
P
E
E
D
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST SC-1A Before Proceeding
START TEST
SC-1C
INSPECT THE
THROTTLE CABLE.
IS THE CABLE
DISCONNECTED OR
DAMAGED?
YES
REPAIR AS
NECESSARY.*
NO
KEY OFF. DISCONNECT
THE SPEED CONTROL
SERVO 4 WAY HARNESS
CONNECTOR.**
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
S/C VACUUM SOLENOID
CONTROL CIRCUIT...
FROM PCM CONNECTOR
TO S/C SERVO
CONNECTOR.
T
E
S
T
S
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR
SPEED
VACUUM
CONTROL
THE OPEN
CONTROL
SOLENOID
CIRCUIT.*
FIG. 1
YES
USING AN OHMMETER,
MEASURE S/C VACUUM
SOLENOID CONTROL
CIRCUIT TO GROUND.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
SPEED CONTROL
VACUUM SOLENOID
CONTROL CIRCUIT.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
S/C VENT SOLENOID
CONTROL CIRCUIT...
FROM PCM CONNECTOR
TO S/C SERVO
CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
SPEED CONTROL VENT
SOLENOID CONTROL
CIRCUIT.*
FIG. 1
YES
USING AN OHMMETER,
MEASURE THE S/C VENT
SOLENOID CONTROL
CIRCUIT TO GROUND.
FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE SHORT
TO GROUND IN THE
SPEED CONTROL VENT
SOLENOID CONTROL
CIRCUIT.*
YES
REPLACE THE SPEED
CONTROL SERVO.*
*Perform Verification TEST VER-4A.
C
O
N
T
R
O
L
**Check connectors - Clean / repair as necessary.
407
S
P
E
E
D
TEST SC-1D
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST SC-1A Before Proceeding
TJ/XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
FIG. 1
TJ BODY
FIG. 2
XJ BODY
FIG. 3
408
TEST SC-1D
S
P
E
E
D
CHECKING THE SPEED CONTROL SYSTEM
Perform TEST SC-1A Before Proceeding
START TEST
SC-1D.
DISCONNECT THE
BRAKE SWITCH
HARNESS
CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
NO
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
MEASURE THE S/C
BRAKE SWITCH OUTPUT
CIRCUIT TO GROUND AT
SERVO CONNECTOR.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
S/C BRAKE SWITCH
OUTPUT CIRCUIT.*
NO
MEASURE THE
RESISTANCE OF BRAKE
SWITCH OUTPUT
CIRCUIT.
FIG. 1 AND (2 OR 3)
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE BRAKE SWITCH
OUTPUT CIRCUIT.*
YES
NOTE: S/C VENT
SOLENOID IS STILL
ACTUATED.
USING A VOLTMETER,
MEASURE THE 12-VOLT
SUPPLY CKT AT BRAKE
SWITCH CONN.
FIG. 2 OR 3
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
CONTINUE TEST
SC-1D ON THE
NEXT PAGE.
YES
USING THE SERVICE
MANUAL PROCEDURE,
CHECK THE BRAKE
SWITCH ADJUSTMENT.
WAS THE BRAKE
SWITCH ADJUSTMENT
OK?
NO
ADJUST THE BRAKE
SWITCH.*
YES
REPLACE THE BRAKE
SWITCH.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
409
C
O
N
T
R
O
L
T
E
S
T
S
S
P
E
E
D
TEST SC-1D
CONTINUED - CHECKING THE SPEED CONTROL SYSTEM
TJ BODY
XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
410
TEST SC-1D
S
P
E
E
D
CONTINUED - CHECKING THE SPEED CONTROL SYSTEM
TEST SC-1D
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF,
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE OF THE
12-VOLT SUPPLY CKT,
PCM TO BRAKE SWITCH.
FIG. 1 OR 2
C
O
N
T
R
O
L
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
12-VOLT SUPPLY
CIRCUIT, PCM TO
BRAKE SWITCH.*
YES
USING AN OHMMETER,
MEASURE THE
12-VOLT SUPPLY
CIRCUIT TO GROUND.
FIG. 3 OR 4
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORT
TO GROUND IN THE
12-VOLT SUPPLY
CIRCUIT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
411
T
E
S
T
S
S
P
E
E
D
TEST SC-2A
CHECKING SPEED CONTROL ON/OFF SWITCH
Perform TEST SC-1A Before Proceeding
TJ/XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
TJ/XJ BODY
FIG. 1
TJ/XJ BODY
FIG. 2
412
TEST SC-2A
S
P
E
E
D
CHECKING SPEED CONTROL ON/OFF SWITCH
Perform TEST SC-1A Before Proceeding
START TEST
SC-2A.
KEY ON, WITH THE
DRB, READ THE
SPEED CONTROL
SWITCH VOLTAGE.
DOES THE DRB
DISPLAY SC/SW
ABOVE 4.0 VOLTS?
YES
CONTINUE TEST
SC-2A ON THE
NEXT PAGE.*
YES
REPLACE THE SPEED
CONTROL ON/OFF/SET
SWITCH.*
NO
DISCONNECT THE
SPEED CONTROL
ON/OFF/SET
SWITCH.**
WITH THE DRB, READ
THE SPEED CONTROL
SWITCH VOLTAGE.
DOES THE DRB
DISPLAY SC/SW
ABOVE 4.0 VOLTS?
NO
DISCONNECT THE S/C
RESUME/COAST/CANCEL
SWITCH HARNESS
CONNECTOR.**
WITH THE DRB, READ
THE SPEED CONTROL
SWITCH VOLTAGE.
DOES THE DRB
DISPLAY SC/SW
ABOVE 4.0 VOLTS?
YES
REPLACE THE SPEED
CONTROL
RESUME/COAST/CANCEL
SWITCH.*
NO
KEY OFF,
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE S/C
SWITCH SIGNAL CKT
FROM S/C SW TO GND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SPEED
CONTROL SWITCH
SIGNAL CIRCUIT FOR
A SHORT TO
GROUND.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
S/C SWITCH SIGNAL
SIGNAL CKT. FIG. 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN IN
THE SPEED CONTROL
SWITCH SIGNAL
CIRCUIT.*
YES
TURN THE IGNITION
OFF.
WAIT ONE MINUTE.
USING AN OHMMETER,
MEASURE BETWEEN THE
S/C SWITCH SIGNAL
CKT AND SENSOR
GROUND. FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SPEED
CONTROL SWITCH
SIGNAL CKT SHORTED
TO THE SENSOR
GROUND CKT.*
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
413
C
O
N
T
R
O
L
T
E
S
T
S
S
P
E
E
D
TEST SC-2A
CONTINUED - CHECKING SPEED CONTROL ON/OFF SWITCH
TJ/XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
FIG. 1
414
TEST SC-2A
S
P
E
E
D
CONTINUED - CHECKING SPEED CONTROL ON/OFF SWITCH
TEST SC-2A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
SPEED CONTROL
ON/OFF/SET
SWITCH.**
KEY ON. USING A
VOLTMETER, MEASURE
THE VOLTAGE OF THE
S/C SWITCH SIGNAL
CIRCUIT FROM...
THE S/C SWITCH
CONNECTOR TO A
GOOD GROUND.
C
O
N
T
R
O
L
IS VOLTAGE ABOVE
6.0 VOLTS?
YES
REPAIR THE S/C
SWITCH SIGNAL
CIRCUIT SHORTED TO
VOLTAGE.*
FIG. 1
NO
TURN THE IGNITION
OFF.
WAIT ONE WAIT.
USING AN OHMMETER,
MEASURE THE SENSOR
GROUND CKT TO
GROUND.
FIG. 1
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE OPEN
SENSOR GROUND
CIRCUIT.*
YES
CONNECT A JUMPER
BETWEEN THE S/C SW
SIGNAL AND GROUND.
DOES THE DRB
DISPLAY S/C SWITCH
IS LESS THAN 1.0
VOLT?
KEY ON. WITH THE
DRB, READ THE S/C
SW VOLTAGE.
YES
REPLACE THE SPEED
CONTROL ON/OFF/SET
SWITCH.*
FIG. 1
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
415
T
E
S
T
S
S
P
E
E
D
TEST SC-3A
CHECKING THE SPEED CONTROL RESUME SWITCH
Perform TEST SC-1A Before Proceeding
TJ/XJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
TJ/XJ BODY
FIG. 1
416
TEST SC-3A
S
P
E
E
D
CHECKING THE SPEED CONTROL RESUME SWITCH
Perform TEST SC-1A Before Proceeding
START TEST
SC-3A.
CONNECT A JUMPER
BETWEEN THE S/C SW
SIGNAL AND GROUND.
DISCONNECT THE S/C
COAST/RESUME
SWITCH HARNESS
CONNECTOR.**
C
O
N
T
R
O
L
DOES THE DRB
DISPLAY S/C SWITCH
IS LESS THAN 1.0
VOLT?
WITH THE DRB, READ
THE S/C SW
VOLTAGE.
YES
REPLACE THE SPEED
CONTROL SET/RESUME
SWITCH.*
FIG. 1
NO
TURN THE IGNITION
OFF.
WAIT ONE MINUTE.
DISCONNECT JUMPER,
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
GROUND CIRCUIT...
FROM THE S/C
COAST/RESUME
CONNECTOR TO A
GOOD GROUND.
FIG. 1
IS RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE OPEN
S/C SW SIGNAL
CIRCUIT TO THE
CLOCKSPRING
CONNECTOR.*
NO
REPAIR THE OPEN
GROUND CIRCUIT TO
S/C COAST/RESUME
SWITCH CONNECTOR.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
417
T
E
S
T
S
S
P
E
E
D
TEST SC-4A
CHECKING THE BRAKE SWITCH SENSE
Perform TEST SC-1A Before Proceeding
TJXJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
TJ BODY
FIG. 1
XJ BODY
FIG. 2
418
TEST SC-4A
S
P
E
E
D
CHECKING THE BRAKE SWITCH SENSE
Perform TEST SC-1A Before Proceeding
START TEST
SC-4A.
WHILE OBSERVING
THE DRB DISPLAY,
PRESS THE COAST
SWITCH SEVERAL
TIMES.
DOES THE DRB
DISPLAY COAST
SWITCH "PRESSED"
OR "RELEASED"?
NO
REPLACE THE COAST
SWITCH.*
YES
WHILE OBSERVING
THE DRB DISPLAY,
PRESS THE BRAKE
PEDAL SEVERAL
TIMES.
DOES THE DRB
DISPLAY BRAKE
SWITCH "PRESSED"
OR "RELEASED"?
YES
PERFORM TEST
SC-1A
CONTINUED.
NO
CONTINUE TEST
SC-4A ON THE
NEXT PAGE.
NO
DISCONNECT THE
BRAKE SWITCH
HARNESS
CONNECTOR.**
KEY ON, USING A
VOLTMETER, MEASURE
THE VOLTAGE OF THE
BRAKE SWITCH
SENSE...
CIRCUIT AT THE
BRAKE SWITCH
CONNECTOR.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
FIG. 1 OR 2
YES
CONNECT A JUMPER
BETWEEN THE BRAKE
SWITCH SENSE AND
GROUND IN BRAKE SW
CONN. FIG. 1 OR 2
WITH THE DRB, READ
THE BRAKE SWITCH
INPUT STATUS.
DOES THE DRB
DISPLAY BRAKE SW
"RELEASED"?
YES
REPLACE THE BRAKE
SWITCH.*
NO
REPAIR THE OPEN
GROUND CIRCUIT.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
419
C
O
N
T
R
O
L
T
E
S
T
S
S
P
E
E
D
TEST SC-4A
CONTINUED - CHECKING THE BRAKE SWITCH SENSE
TJ BODY
C
O
N
T
R
O
L
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
420
TEST SC-4A
S
P
E
E
D
CONTINUED - CHECKING THE BRAKE SWITCH SENSE
TEST SC-4A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF,
DISCONNECT THE
POWERTRAIN CONTROL
MODULE HARNESS
CONNECTOR.**
IS ANY TERMINAL
DAMAGED, PUSHED
OUT OR MISWIRED?
YES
REPAIR AS
NECESSARY.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
BRAKE SWITCH SENSE
CIRCUIT...
AT PCM CONNECTOR
TO GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE BRAKE
SWITCH SENSE
CIRCUIT, SHORTED
TO GROUND.*
FIG. 1 OR 2
NO
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE BRAKE
SWITCH SENSE CKT.
FROM THE PCM TO
THE BRAKE SWITCH.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPAIR THE OPEN
BRAKE SWITCH SENSE
CIRCUIT.
BRAKE SWITCH TO
PCM.*
*Perform Verification TEST VER-4A.
**Check connectors - Clean / repair as necessary.
421
C
O
N
T
R
O
L
T
E
S
T
S
S
P
E
E
D
TEST SC-5A
CHECKING THE SPEED CONTROL OPERATION
Perform TEST SC-1A Before Proceeding
NOTES
C
O
N
T
R
O
L
T
E
S
T
S
422
TEST SC-5A
CHECKING THE SPEED CONTROL OPERATION
Perform TEST SC-1A Before Proceeding
At this time the speed control switch and servo functions appear to operate properly. Using the DRB,
monitor the speed control ‘‘cutout’’ status. Road test the vehicle at speeds over 35 mph and attempt
to set the speed control. The following items will not allow the speed control to set. The last or most
recent cause for speed control not to set is indicated by the ‘‘Denied’’ status.
Denied Message
ON/OFF
The powertrain control module does not see an ‘‘ON’’ signal from the
switch.
SPEED
The vehicle speed as seen by the powertrain control module is not greater
than 36 mph.
RPM
The engine rpm is excessively high.
BRAKE
The brake switch sense circuit is open indicating to the powertrain control
module that the brakes are applied. The sense circuit is grounded through
the brake pedal switch when the brakes are released.
P/N
The park/neutral switch sense circuit is malfunctioning indicating the powertrain control module that the transmission is not in gear. The sense circuit is grounded (XJ4 SPEED A/T) or opened (TJ/XJ 3 SPEED A/T)
through the park/neutral switch when the transmission is in park or neutral.
RPM/SPD
The PCM senses excessive engine rpm for a given vehicle speed.
SOL FLT
The powertrain control module senses a servo solenoid circuit trouble
code that is maturing or set in memory.
423
S
P
E
E
D
C
O
N
T
R
O
L
T
E
S
T
S
C
H
A
R
G
I
N
G
TEST CH-1A
CHARGING SYSTEM NO CODE TEST
Perform TEST DTC Before Proceeding
TJ/XJ BODY
T
E
S
T
S
FIG. 1
424
TEST CH-1A
CHARGING SYSTEM NO CODE TEST
Perform TEST DTC Before Proceeding
START TEST
CH-1A.
USING DRB, READ
TROUBLE CODES.
ARE THERE ANY
CHARGING SYSTEM
TROUBLE CODES?
YES
PERFORM DTC
TEST
T
E
S
T
S
NO
BATTERY CONDITION
MUST BE VERIFIED
PRIOR TO THIS TEST
INSPECT THE
GENERATOR BELT
TENSION AND
CONDITION.
IS THE GENERATOR
BELT OK?
NO
REPAIR AS
NECESSARY.*
YES
PERFORM DTC
TEST
YES
START ENGINE, TURN
ON ALL ACCESSORIES
AND RAISE THE ENGINE
SPEED TO 2000 RPM
FOR 30 SECONDS.
RETURN THE ENGINE
TO IDLE SPEED AND
READ CODES.
ARE THERE ANY
CHARGING SYSTEM
TROUBLE CODES?
NO
TURN ENGINE OFF
(IGNITION ON).
USING DRB, ACTUATE
THE GENERATOR
FIELD.
DRIVER TERMINAL AT
THE BACK OF THE
GENERATOR.
USING A VOLTMETER
BACKPROBE THE
GENERATOR FIELD...
FIG. 1
NOTE: THE VOLTAGE
SHOULD CYCLE FROM
HIGH TO LOW EVERY
1.4 SECOND.
WHILE MONITORING THE
VOLTMETER, WIGGLE
THE FIELD TERMINALS
BACK TO THE PCM AND
ASD RELAY.
WAS THERE ANY
INTERRUPTION IN
THE HIGH AND LOW
VOLTAGE CYCLE?
YES
REPAIR THE WIRE OR
CONNECTOR WHERE
WIGGLING
INTERRUPTED THE
VOLTAGE CYCLE.*
NO
CONTINUE TEST
CH-1A ON THE
NEXT PAGE.
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
425
C
H
A
R
G
I
N
G
C
H
A
R
G
I
N
G
TEST CH-1A
CONTINUED - CHARGING SYSTEM NO CODE TEST
TJ/XJ BODY
T
E
S
T
S
FIG. 1
426
TEST CH-1A
C
H
A
R
G
I
N
G
CONTINUED - CHARGING SYSTEM NO CODE TEST
TEST CH-1A
CONTINUED FROM
THE PREVIOUS
PAGE.
CAUTION: ENSURE ALL
WIRES ARE CLEAR OF
THE ENGINE’S MOVING
PARTS.
MEASURE BETWEEN THE
GENERATOR (12V) B+
TERMINAL AND THE
BATTERY (+) SIDE.
FIG. 1
USE A VOLTMETER IN
THE FOLLOWING
STEP.
IS THE VOLTAGE
ABOVE 0.4 VOLT?
START THE ENGINE.
YES
REPAIR THE B (+)
CIRCUIT FOR HIGH
RESISTANCE BETWEEN
THE GENERATOR AND
THE BATTERY.*
NO
KEY OFF.
USE A VOLTMETER IN
THE FOLLOWING
STEP.
CAUTION: ENSURE ALL
WIRES ARE CLEAR OF
THE ENGINE’S MOVING
PARTS.
MEASURE BETWEEN
THE GENERATOR CASE
AND BATTERY (-)
SIDE.
IS THE VOLTAGE
ABOVE 0.1 VOLT?
START THE ENGINE.
YES
REPAIR GENERATOR
GROUND FOR HIGH
RESISTANCE
(GENERATOR CASE TO
BATTERY (-) SIDE.)*
NO
USING THE DRB,
READ BATTERY
VOLTAGE AND
RECORD.
USING A VOLTMETER,
MEASURE THE
VOLTAGE ACROSS THE
BATTERY TERMINALS.
RECORD SECOND
VOLTAGE READING.
COMPARE THE TWO
VOLTAGE READINGS.
IS VOLTAGE
DIFFERENCE LESS
THAN ONE VOLT?
YES
TEST COMPLETE.*
NO
CONTINUE TEST
CH-1A ON THE
NEXT PAGE.
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
427
T
E
S
T
S
C
H
A
R
G
I
N
G
TEST CH-1A
CONTINUED - CHARGING SYSTEM NO CODE TEST
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
428
TEST CH-1A
C
H
A
R
G
I
N
G
CONTINUED - CHARGING SYSTEM NO CODE TEST
TEST CH-1A
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE PCM
HARNESS
CONNECTORS.**
KEY OFF.
KEY ON. USING A
VOLTMETER, MEASURE
FUSED B+ AT PCM
CONNECTOR.
FIG. 1 OR 2
IS THE VOLTAGE
WITHIN ONE VOLT OF
THE RECORDED DRB
READING?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
YES
REPAIR THE B (+)
CIRCUIT FOR HIGH
RESISTANCE BETWEEN
THE PCM FUSED B+
AND THE BATTERY.*
*Perform Verification TEST VER-3A.
**Check connectors - Clean / repair as necessary.
429
T
E
S
T
S
N TEST NS-SEL
O
NO START SELECTION MENU
Perform TEST DTC Before Proceeding
S
T
A
R
T
NOTES
T
E
S
T
S
430
TEST NS-SEL
N
O
NO START SELECTION MENU
Perform TEST DTC Before Proceeding
NOTE: For all component locations, REFER TO GENERAL INFORMATION section 4.0 in this
manual
NOTE: The battery must be fully charged before performing any test in this manual.
NOTE: If the engine will not crank or cranks but will not run, be sure to check the SKIM module for
proper communication and trouble codes.
NOTE: If there are any trouble codes present they must be repaired before continuing with the No
Start Symptom diagnostics.
NOTE: If the DRB does not power up, REFER TO GENERAL INFORMATION section 3.5.1.
Below you will find a recommended procedure to correct a No Start Problem by symptom. They
should be performed in the order that they are listed.
Qualifying a no start condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-1A
Checking the fuel system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-2A
Checking engine mechanical systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-3A
Repairing low fuel pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-4A
Checking the fuel pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-5A
Repairing ‘‘NO RESPONSE CONDITION’’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-6A
Engine starts and the DRB displays ‘‘NO RESPONSE’’. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-6B
Checking the idle air control motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-7A
Repairing a start and stall condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-8A
Repairing a no-crank condition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .NS-9A
431
S
T
A
R
T
T
E
S
T
S
N
O
TEST NS-1A
QUALIFYING A NO START CONDITION
Perform TEST NS-SEL Before Proceeding
S
T
A
R
T
T
E
S
T
S
FIG. 1
432
TEST NS-1A
N
O
QUALIFYING A NO START CONDITION
Perform TEST NS-SEL Before Proceeding
START TEST
NS-1A.
CONNECT THE CABLE
TO A SPARK TESTER.
S
T
A
R
T
KEY OFF.
DISCONNECT THE
SPARK PLUG CABLE
AT SPARK PLUG
#1.**
CONNECT THE SPARK
TESTER TO A GOOD
GROUND.
T
E
S
T
S
WHILE CRANKING THE
ENGINE FOR 10
SECONDS, WATCH FOR
SPARK.
FIG. 1
NO
IS THERE GOOD
SPARK?
YES
DOES THE VEHICLE
START AND STALL?
YES
PERFORM TEST
NS-7A.
NO
PERFORM TEST
NS-2A.
KEY OFF.
CONNECT THE CABLE
TO A SPARK TESTER.
REMOVE THE COIL
SECONDARY CABLE
FROM THE
DISTRIBUTOR.
CONNECT THE SPARK
TESTER TO A GOOD
GROUND.
FIG. 1
*Perform Verification TEST VER-1A.
WHILE CRANKING THE
ENGINE FOR 10
SECONDS, WATCH FOR
SPARK.
CONTINUE TEST
NS-1A ON THE
NEXT PAGE.
FIG. 1
**Check connectors - Clean / repair as necessary.
433
N
O
TEST NS-1A
CONTINUED - QUALIFYING A NO START CONDITION
S
T
A
R
T
T
E
S
T
S
FIG. 1
FIG. 2
434
TEST NS-1A
N
O
CONTINUED - QUALIFYING A NO START CONDITION
TEST NS-1A
CONTINUED FROM
THE PREVIOUS
PAGE.
IS THERE GOOD
SPARK?
YES
REPAIR THE
SECONDARY
IGNITION:
DISTRIBUTOR CAP,
ROTOR, CABLES.*
T
E
S
T
S
NO
KEY OFF.
REMOVE THE COIL
SECONDARY CABLE.
USE AN OHMMETER IN
THE FOLLOWING
STEP.
MEASURE THE
RESISTANCE OF THE
COIL SECONDARY
CABLE.
IS THE RESISTANCE
WITHIN THE
SPECIFICATION?
YES
REPLACE THE COIL
SECONDARY CABLE.*
NO
REPAIR THE
DISTRIBUTOR DRIVE
SYSTEM.*
FIG. 1
NO
REMOVE THE
DISTRIBUTOR CAP.
WHILE CRANKING THE
ENGINE, WATCH FOR
THE ROTOR TO TURN.
DID THE ROTOR TURN
WHEN THE ENGINE
WAS CRANKED?
FIG. 2
YES
REINSTALL THE
DISTRIBUTOR CAP
AND IGNITION COIL
CABLE.
DISCONNECT THE
IGNITION COIL
CONNECTOR. INSPECT
ALL TERMINALS.
IS ANY TERMINAL
DAMAGED, PUSHED
OUT, OR MISWIRED?
YES
REPAIR TERMINAL(S)
FOR DAMAGE,
PUSHOUT, OR
MISWIRING.*
NO
KEY ON.
USING THE DRB,
ACTUATE THE
GENERATOR FIELD.
*Perform Verification TEST VER-1A.
CONTINUE TEST
NS-1A ON THE
NEXT PAGE.
**Check connectors - Clean / repair as necessary.
435
S
T
A
R
T
N
O
S
T
A
R
T
TEST NS-1A
CONTINUED - QUALIFYING A NO START CONDITION
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
436
TEST NS-1A
N
O
CONTINUED - QUALIFYING A NO START CONDITION
TEST NS-1A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING A VOLTMETER,
PROBE THE ASD RELAY
OUTPUT CIRCUI IN THE
COIL CONNECTOR.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN
ASD RELAY OUTPUT
CKT FROM COIL
CONNECTOR TO
SPLICE.*
YES
CONTINUE TEST
NS-1A ON THE
NEXT PAGE
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
437
S
T
A
R
T
T
E
S
T
S
N
O
TEST NS-1A
CONTINUED - QUALIFYING A NO START CONDITION
S
T
A
R
T
T
E
S
T
S
FIG. 1
438
TEST NS-1A
N
O
CONTINUED - QUALIFYING A NO START CONDITION
S
T
A
R
T
KEY OFF.
TEST NS-1A
CONTINUED FROM
PREVIOUS PAGE
USE AN OHMMETER IN
THE FOLLOWING TWO
STEPS.
T
E
S
T
S
MEASURE THE
RESISTANCE BETWEEN
THE PRIMARY
TERMINALS OF THE
IGNITION COIL.FIG. 1
IS THE PRIMARY
RESISTANCE BETWEEN
0.95 - 1.20 OHMS?
NO
REPLACE THE
IGNITION COIL.*
NO
REPLACE THE
IGNITION COIL.*
YES
MEASURE THE
RESISTANCE BETWEEN
THE PRIMARY AND
SECONDARY TERMINALS
OF THE COIL. FIG. 1
IS THE SECONDARY
RESISTANCE BETWEEN
11,300 - 15,300
OHMS?
YES
CONTINUE TEST
NS-1A ON THE
NEXT PAGE
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
439
N
O
S
T
A
R
T
TEST NS-1A
CONTINUED - QUALIFYING A NO START CONDITION
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
440
TEST NS-1A
N
O
CONTINUED - QUALIFYING A NO START CONDITION
TEST NS-1A
CONTINUED FROM
THE PREVIOUS
PAGE.
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF
THE...
S
T
A
R
T
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
IGNITION COIL DRIVER
CIRCUIT AT THE PCM
CONNECTOR TO GROUND.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE
IGNITION COIL
DRIVER CIRCUIT FOR
A SHORT TO GROUND.
FIG. 1 OR 2
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF THE
COIL DRIVER
CIRCUIT...
FROM THE IGNITION
COIL TO THE PCM
CONNECTOR.
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
FIG. 1 OR 2
REPAIR THE
IGNITION COIL
DRIVER FROM PCM TO
COIL CONNECTOR FOR
AN OPEN.*
NO
CHECK VALVE
TIMING. REFER TO
APPLICABLE SERVICE
MANUAL.
IS VALVE TIMING
WITHIN
SPECIFICATIONS?
NO
REPAIR THE ENGINE
VALVE TIMING AS
NECESSARY.*
YES
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
441
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-2A
CHECKING THE FUEL SYSTEM
Perform TEST NS-SEL Before Proceeding
NOTES
T
E
S
T
S
442
TEST NS-2A
N
O
CHECKING THE FUEL SYSTEM
Perform TEST NS-SEL Before Proceeding
START TEST
NS-2A.
ENSURE THE
THROTTLE CABLE IS
NOT HOLDING THE
THROTTLE OPEN.
IS THE THROTTLE
BEING HELD OPEN BY
THE CABLE?
YES
REPAIR THE
CONDITION THAT IS
HOLDING THE
THROTTLE OPEN.*
NO
USING THE DRB, GO
INTO ENGINE AND
SELECT MONITORED
DISPLAY, NO START.
DOES THE DRB
DISPLAY "VEH THEFT
SECURITY: FUEL
ON"?
YES
CONTINUE TEST
NS-2A ON THE
NEXT PAGE.
NO
REFER TO THE SKIS
SECTION IN THIS
MANUAL AND PERFORM
TEST SK-1A.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
443
S
T
A
R
T
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-2A
CONTINUED - CHECKING THE FUEL SYSTEM
NOTES
T
E
S
T
S
444
TEST NS-2A
N
O
CONTINUED - CHECKING THE FUEL SYSTEM
TEST NS-2A
CONTINUED FROM
THE PREVIOUS
PAGE.
NOTE: IT MAY BE
NECESSARY TO USE A
MECHANICS
STETHOSCOPE IN THE
NEXT STEP.
S
T
A
R
T
USING THE DRB,
ACTUATE THE FUEL
SYSTEM.
LISTEN FOR FUEL
PUMP OPERATION AT
THE FUEL TANK.
CAN THE FUEL PUMP
OPERTION BE HEARD?
NO
PERFORM TEST
NS-5A.
YES
KEY OFF.
WARNING: THE FUEL
SYSTEM MUST BE
OPENED AND MAY BE
UNDER HIGH PRESSURE.
SEE GENERAL INFO 9.0
NOTE: THE FUEL
TANK MUST BE AT
LEAST 1/4 FULL FOR
THE FOLLOWING
TESTS.
INSTALL A FUEL
PRESSURE GAUGE TO
THE FUEL SYSTEM.
KEY ON.
USING THE DRB,
ACTUATE THE FUEL
SYSTEM.
READ THE FUEL
PRESSURE GAUGE.
IS THE FUEL
PRESSURE ABOVE
54.2 PSI?
YES
REPLACE FUEL
FILTER/REGULATOR
AND PRIMARY
FILTER.*
NO
IS THE FUEL
PRESSURE BELOW
44.2 PSI?
YES
PERFORM TEST
NS-4A.
YES
PERFORM TEST
NS-7A.
NO
DID THE VEHICLE
INITIALLY START &
STALL REPEATEDLY?
NO
PERFORM TEST
NS-3A.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
445
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-3A
CHECKING ENGINE MECHANICAL SYSTEMS
Perform TEST NS-SEL Before Proceeding
2.5L
T
E
S
T
S
FIG. 1
4.0L
FIG. 2
446
TEST NS-3A
N
O
CHECKING ENGINE MECHANICAL SYSTEMS
Perform TEST NS-SEL Before Proceeding
START TEST
NS-3A.
S
T
A
R
T
INSPECT SPARK PLUG
CABLES FOR CORRECT
FIRING ORDER.
FIG. 1 OR 2
ARE ALL SPARK PLUG
CABLES POSITIONED
CORRECTLY?
NO
REINSTALL SPARK
PLUG CABLES AS
NECESSARY.*
NO
REPAIR THE ENGINE
VALVE TIMING AS
NECESSARY.*
NO
REPAIR AS
NECESSARY.*
NO
REPAIR AS
NECESSARY.*
YES
KEY OFF.
USING SERVICE
MANUAL PROCEDURES,
CHECK VALVE
TIMING.
IS VALVE TIMING
WITHIN
SPECIFICATIONS?
YES
CHECK EXHAUST
SYSTEM FOR ANY
RESTRICTIONS.
IS THE EXHAUST
FREE OF ANY
RESTRICTIONS?
YES
REMOVE ASD RELAY.
REMOVE SPARK
PLUGS.
USING SERVICE
MANUAL PROCEDURES,
CHECK ENGINE
COMPRESSION.
IS ENGINE
COMPRESSION WITHIN
SPECIFICATIONS?
YES
REPLACE POWERTRAIN
CONTROL MODULE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
447
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-4A
REPAIRING LOW FUEL PRESSURE
Perform TEST NS-SEL Before Proceeding
NOTES
T
E
S
T
S
448
TEST NS-4A
N
O
REPAIRING LOW FUEL PRESSURE
Perform TEST NS-SEL Before Proceeding
START TEST
NS-4A.
INSPECT FUEL LINES
FROM FILTER/REG TO
FUEL RAIL FOR
RESTRICTION.
IS THERE ANY
RESTRICTION?
YES
REPAIR RESTRICTED
FUEL LINES.*
T
E
S
T
S
NO
REPLACE FUEL PUMP
MODULE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
449
S
T
A
R
T
N
O
S
T
A
R
T
TEST NS-5A
CHECKING THE FUEL PUMP
Perform TEST NS-2A Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
450
TEST NS-5A
N
O
CHECKING THE FUEL PUMP
Perform TEST NS-2A Before Proceeding
START TEST
NS-5A.
S
T
A
R
T
NOTE: THE FUEL
PUMP RELAY STILL
ACTUATING.
TOUCH THE FUEL
PUMP RELAY.
IS THE FUEL PUMP
RELAY OPERATING?
NO
PERFORM TEST
TC-101A.
FIG. 1 OR 2
YES
DISCONNECT THE
FUEL PUMP RELAY.**
KEY OFF.
FIG. 1 OR 2
USING A VOLTMETER,
MEASURE THE FUEL
PUMP RELAY FUSED
B(+) CIRCUIT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUEL
PUMP RELAY B(+)
CIRCUIT FOR AN
OPEN.*
YES
CONTINUE TEST
NS-5A ON THE
NEXT PAGE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
451
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-5A
CONTINUED - CHECKING THE FUEL PUMP
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
452
TEST NS-5A
N
O
CONTINUED - CHECKING THE FUEL PUMP
TEST NS-5A
CONTINUED FROM
THE PREVIOUS
PAGE.
S
T
A
R
T
INSTALL A SUBSTITUTE
RELAY OF THE SAME
PART NUMBER FOR THE
FUEL PUMP RELAY.
ATTEMPT TO START
THE ENGINE
DOES THE ENGINE
START?
YES
REPLACE THE FUEL
PUMP RELAY.*
NO
REINSTALL THE
ORIGINAL FUEL PUMP
RELAY.
CAUTION: IT IS
CRITICAL THAT THE
FUEL PUMP CONNECTOR
HAS A CLEAN AND
TIGHT CONNECTION.**
DISCONNECT THE
FUEL PUMP HARNESS
CONNECTOR.**
KEY ON.
USING THE DRB,
ACTUATE THE FUEL
SYSTEM.
USING A VOLTMETER,
MEASURE THE FUEL
PUMP RELAY OUTPUT
CIRCUIT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE FUEL
PUMP RELAY OUTPUT
CIRCUIT FOR AN
OPEN.*
YES
USING THE DRB,
STOP THE ACTUATION
TEST.
USING AN OHMMETER,
MEASURE THE FUEL
PUMP GND CIRCUIT IN
THE FUEL PUMP CONN.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE FUEL
PUMP GROUND
CIRCUIT FOR AN
OPEN.*
YES
REPLACE THE FUEL
PUMP.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
453
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-6A
REPAIRING - NO RESPONSE CONDITION
Perform TEST NS-SEL Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
454
TEST NS-6A
N
O
REPAIRING - NO RESPONSE CONDITION
Perform TEST NS-SEL Before Proceeding
START TEST
NS-6A.
S
T
A
R
T
KEY OFF.
DISCONNECT THE PCM
HARNESS
CONNECTOR.**
T
E
S
T
S
USING AN OHMMETER,
PROBE BOTH GROUND
CIRCUITS AT PCM
CONNECTOR.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS AT
BOTH TERMINALS?
NO
REPAIR THE
GROUND(S) AT THE
POWERTRAIN CONTROL
MODULE FOR AN
OPEN.*
YES
KEY ON.
USING A VOLTMETER,
PROBE FUSED IGN
SWITCH OUTPUT
CIRCUIT.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE OPEN
FUSED IGN SWITCH
OUTPUT CIRCUIT
BETWEEN PCM &
IGNITION SWITCH.*
YES
CONTINUE TEST
NS-6A ON THE
NEXT PAGE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
455
N
O
S
T
A
R
T
TEST NS-6A
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TJ BODY
XJ BODY
TJ BODY
XJ BODY
T
E
S
T
S
FIG. 1
FIG. 2
456
TEST NS-6A
N
O
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TEST NS-6A
CONTINUED FROM
THE PREVIOUS
PAGE.
PROBE FUSED B(+)
CKT IN THE PCM
CONNECTOR.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
YES
PERFORM TEST
NS-6D.
S
T
A
R
T
FIG. 1 OR 2
T
E
S
T
S
NO
REMOVE THE FUSE IN
THE PDC THAT
SUPPLIES FUSED B(+)
TO PCM CAVITY A22.
FIG. 1 OR 2
NO
INSPECT THE FUSE.
IS THE FUSE OK?
CONTINUE TEST
NS-6A ON THE
NEXT PAGE.
YES
WITH A VOLTMETER,
MEASURE THE B(+)
SIDE OF THE FUSE
SOCKET.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR THE B(+)
CIRCUIT FROM FUSE
TO THE BATTERY FOR
AN OPEN.*
YES
REPAIR THE FUSED
B(+) CIRCUIT FROM
FUSE TO PCM FOR AN
OPEN.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
457
N
O
S
T
A
R
T
TEST NS-6A
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TJ BODY
XJ BODY
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
458
TEST NS-6A
N
O
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TEST NS-6A
CONTINUED FROM
THE PREVIOUS
PAGE.
KEY OFF.
DISCONNECT THE
AUTO SHUTDOWN
RELAY.**
S
T
A
R
T
USE AN OHMMETER IN
THE FOLLOWING
STEP.
T
E
S
T
S
NOTE: THE
PREVIOUSLY
INSPECTED FUSE
SHOULD STILL BE
REMOVED.
MEASURE THE
RESISTANCE OF THE
FUSED B(+) CKT AT
PCM CONN TO GND.
FIG. 3 OR 4
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE FUSED
B(+) CIRCUIT FOR A
SHORT TO GROUND.
REPLACE FUSE.*
NO
USING AN OHMMETER,
MEASURE THE
RESISTANCE OF
THE...
ASD RELAY OUTPUT
CKT AT THE ASD
RELAY CONNECTOR TO
GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
CONTINUE TEST
NS-6A ON THE
NEXT PAGE.
NO
PERFORM TEST
NS-6C.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
459
N
O
S
T
A
R
T
TEST NS-6A
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
460
TEST NS-6A
N
O
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TEST NS-6A
CONTINUED FROM
THE PREVIOUS
PAGE.
S
T
A
R
T
DISCONNECT THE
CONNECTOR FOR EACH
OXYGEN SENSOR.**
USING AN OHMMETER,
MEASURE THE ASD
RELAY OUTPUT CIRCUIT
FOR RESISTANCE TO
GROUND. FIG. 1 OR 2
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
MEASURE THE ASD
RELAY OUTPUT CKT
IN EACH O2 SENSOR
FOR RESISTANCE TO
GND.
NO
NOTE: THE OXYGEN
SENSORS MUST REMAIN
DISCONNECTED FOR THE
REMAINDER OF THE
TEST.
DISCONNECT THE
IGNITION COIL
CONNECTOR.
REPLACE THE OXYGEN
SENSOR THAT HAS
CONTINUNITY TO
GROUND.
REPLACE FUSE.*
MEASURE THE ASD
RELAY OUTPUT CIRCUIT
FOR RESISTANCE TO
GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
REPLACE THE
IGNITION COIL.
REPLACE FUSE.*
NO
DISCONNECT THE
GENERATOR FIELD
CONNECTOR.
MEASURE THE ASD
RELAY OUTPUT CIRCUIT
FOR RESISTANCE TO
GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
REPAIR GENERATOR
FOR SHORT TO
GROUND.
REPLACE FUSE.*
NO
CONTINUE TO
MONITOR OHMMETER
DISPLAY WHILE
DISCONNECTING EACH
FUEL INJECTOR.
IS THE RESISTANCE
ABOVE 5.0 OHMS
WHEN ANY OF THE
INJECTORS ARE
DISCONNECTED?
YES
REPLACE THE FUEL
INJECTOR THAT
CAUSED A CHANGE IN
RESISTANCE.
REPLACE FUSE.*
NO
REPAIR ASD RELAY
OUTPUT CIRCUIT FOR
A SHORT TO GROUND.
REPLACE FUSE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
461
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-6B
REPAIRING - NO REPONSE CONDITION
Perform TEST NS-6A Before Proceeding
TJ BODY
XJ BODY
T
E
S
T
S
FIG. 1
FIG. 2
TJ BODY
XJ BODY
FIG. 3
FIG. 4
462
TEST NS-6B
N
O
REPAIRING - NO REPONSE CONDITION
Perform TEST NS-6A Before Proceeding
WAS THE IGNITION
ON WHEN THE "NO
RESPONSE" MESSAGE
WAS DISPLAYED?
START TEST
NS-6B.
NO
TURN IGNITION ON
TO GET A RESPONSE.
YES
KEY OFF.
TEST COMPLETE.*
DISCONNECT DRB
FROM THE DATA LINK
CONNECTOR (DLC).
DISCONNECT THE PCM
HANRESS
CONNECTORS.**
USE AN OHMMETER IN
THE FOLLOWING
STEPS.
MEASURE THE
RESISTANCE BETWEEN
THE SCI TRANSMIT
CIRCUIT AND GROUND.
FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SCI
TRANSMIT CIRCUIT
FOR A SHORT TO
GROUND.*
NO
MEASURE THE
RESISTANCE BETWEEN
THE SCI RECEIVE
CIRCUIT AND GROUND.
FIG. 1 0R 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SCI
RECEIVE CIRCUIT
FOR A SHORT TO
GROUND.*
NO
MEASURE THE
RESISTANCE OF THE
SCI TRANSMIT CIRCUIT
FROM THE PCM TO THE
DLC. FIG. 3 OR 4
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE SCI
TRANSMIT CIRCUIT
FOR AN OPEN.*
YES
CONTINUE TEST
NS-6B ON THE
NEXT PAGE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
463
S
T
A
R
T
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-6B
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
464
TEST NS-6B
N
O
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TEST NS-6B
CONTINUED FROM
THE PREVIOUS
PAGE.
MEASURE THE
RESISTANCE OF THE
SCI RECEIVE CIRCUIT
FROM THE PCM TO THE
DLC. FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
NO
REPAIR THE SCI
RECEIVE CIRCUIT
FOR AN OPEN.*
T
E
S
T
S
YES
CONNECT THE DRB TO
A FUNCTIONAL DATA
LINK ON ANOTHER
VEHICLE.
KEY ON.
USING THE DRB,
ATTEMPT TO READ
TROUBLE CODES.
DID THE DRB
DISPLAY "NO
RESPONSE"?
NO
REPLACE THE
INITIAL VEHICLE’S
POWERTRAIN CONTROL
MODULE.*
YES
SUBSTITUTE ANOTHER
DRB ADAPTER CABLE.
USING THE DRB,
ATTEMPT TO READ
TROUBLE CODES.
DID THE DRB
DISPLAY "NO
RESPONSE"?
NO
REPLACE THE DRB
ADAPTER CABLE.*
YES
HAVE THE DRB
REPAIRED OR
REPLACED.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
465
S
T
A
R
T
N
O
S
T
A
R
T
TEST NS-6C
REPAIRING - NO RESPONSE CONDITION
Perform TEST NS-6A Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
466
TEST NS-6C
N
O
REPAIRING - NO RESPONSE CONDITION
Perform TEST NS-6A Before Proceeding
START TEST
NS-6C.
S
T
A
R
T
DISCONNECT THE
FUEL PUMP
ELECTRICAL
CONNECTOR.**
USING AN OHMMETER,
MEASURE THE FUEL
PUMP RELAY OUTPUT
CKT AT THE RELAY
CONN. FIG. 1 OR 2
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE FUEL
PUMP RELAY OUTPUT
CIRCUIT FOR A
SHORT TO GROUND.
REPLACE FUSE.*
NO
REPLACE THE FUEL
PUMP.
REPLACE FUSE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
467
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-6D
REPAIRING - NO RESPONSE CONDITION
Perform TEST NS-6A Before Proceeding
TJ/XJ BODY
T
E
S
T
S
TJ/XJ BODY
FIG. 1
468
TEST NS-6D
N
O
REPAIRING - NO RESPONSE CONDITION
Perform TEST NS-6A Before Proceeding
START TEST
NS-6D.
DISCONNECT THE
THROTTLE POSITION
SENSOR.**
CONNECT A
VOLTMETER TO
THE...
S
T
A
R
T
RECONNECT ALL
DISCONNECTED
CONNECTORS.
T
E
S
T
S
KEY ON.
THROTTLE POSITION
SENSOR 5 VOLT
SUPPLY CIRCUIT.
IS THE VOLTAGE
BELOW 4.0 VOLTS?
NO
REPLACE THE
POWERTRAIN CONTROL
MODULE.*
NO
REPLACE THE
CAMSHAFT SENSOR.*
NO
REPLACE THE
CRANKSHAFT
SENSOR.*
NO
REPLACE THE MAP
SENSOR.*
FIG. 1
YES
DISCONNECT THE
CAMSHAFT SENSOR.**
IS THE VOLTAGE
BELOW 4.0 VOLTS?
READ VOLTMETER.
YES
DISCONNECT THE
CRANKSHAFT
SENSOR.**
IS THE VOLTAGE
BELOW 4.0 VOLTS?
READ VOLTMETER.
YES
DISCONNECT THE MAP
SENSOR.**
IS THE VOLTAGE
BELOW 4.0 VOLTS?
READ VOLTMETER.
YES
CONTINUE TEST
NS-6D ON THE
NEXT PAGE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
469
N
O
TEST NS-6D
CONTINUED - REPAIRING - NO RESPONSE CONDITION
S
T
A
R
T
T
E
S
T
S
470
TEST NS-6D
N
O
CONTINUED - REPAIRING - NO RESPONSE CONDITION
TEST NS-6D
CONTINUED FROM
THE PREVIOUS
PAGE.
DISCONNECT THE
VEHICLE SPEED
SENSOR.** READ THE
VOLTMETER.
IS THE VOLTAGE
BELOW 4.0 VOLTS?
NO
REPLACE THE
VEHICLE SPEED
SENSOR.*
YES
DISCONNECT THE
TRANSMISSION
SOLENOID CONNECTOR
IF EQUIPPED.**
IS THE VOLTAGE
BELOW 4.0 VOLTS?
READ VOLTMETER.
NO
REPLACE THE
GOVERNOR/TEMP
PRESSURE SENSOR.*
YES
DISCONNECT THE
VOLTMETER.
MEASURE THE
VOLTAGE OF THE
SENSOR GROUND
CIRCUIT.
IS THE VOLTAGE
ABOVE 1.0 VOLT?
YES
REPAIR THE SENSOR
GROUND CIRCUIT
SHORTED TO
VOLTAGE.*
NO
KEY OFF.
DISCONNECT THE
POWERTRAIN CONTROL
MODULE.**
WITH AN OHMMETER
MEASURE THE
RESISTANCE OF THE
5-VOLT SUPPLY
CIRCUIT...
DISCONNECT THE
VOLTMETER.
TO GROUND AT THE
POWERTRAIN CONTROL
MODULE CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORTED
5-VOLT SUPPLY
(PRIMARY) OR
(SECONDARY) SHORTED
TO GROUND.*
NO
MEASURE THE
RESISTANCE OF THE
5-VOLT SUPPLY
CIRCUIT...
TO SENSOR GROUND
CKT AT THE
POWERTRAIN CONTROL
MODULE.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPAIR THE SHORTED
5-VOLT SUPPLY
(PRIMARY) OR
(SECONDARY) SHORTED
TO SENSOR GND CKT.*
NO
PERFORM TEST
NS-6B.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
471
S
T
A
R
T
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-7A
CHECKING THE IDLE AIR CONTROL MOTOR
Perform TEST NS-SEL Before Proceeding
TJ/XJ BODY
T
E
S
T
S
FIG. 1
472
TEST NS-7A
N
O
CHECKING THE IDLE AIR CONTROL MOTOR
Perform TEST NS-SEL Before Proceeding
START TEST
NS-7A.
IS THERE A IAC
MOTOR DTC?
YES
PERFORM TEST
TC-25A.
S
T
A
R
T
NO
HOLD THE ENGINE
THROTTLE 1/4 OF
THE WAY DOWN AND
ATTEMPT TO START
ENGINE.
DOES THE ENGINE
START AND STAY
RUNNING AND THEN
STALL WHEN THROTTLE
IS RELEASED?
NO
PERFORM TEST
NS-8A.
YES
PERFORM TEST
TC-25B.
YES
PERFORM TEST
TC-25C.
YES
PERFORM TEST
TC-25D.
YES
PERFORM TEST
TC-25E.
YES
DISCONNECT THE
IDLE AIR CONTROL
MOTOR CONNECTOR.
WITH DRB, ACTUATE
THE IDLE AIR
CONTROL MOTOR.
PUT A VOLTMETER.
MEASURE THE IDLE
AIR CONTROL #1
DRIVER CKT.
DID THE VOLTAGE
STAY BELOW 1.0
VOLT?
FIG. 1
NO
MEASURE THE IDLE
AIR CONTROL #2
DRIVER CKT.
DID THE VOLTAGE
STAY BELOW 1.0
VOLT?
FIG. 1
NO
MEASURE THE IDLE
AIR CONTROL #3
DRIVER CKT.
DID THE VOLTAGE
STAY BELOW 1.0
VOLT?
FIG. 1
NO
MEASURE THE IDLE
AIR CONTROL #4
DRIVER CKT.
DID THE VOLTAGE
STAY BELOW 1.0
VOLT?
FIG. 1
NO
CONTINUE TEST
NS-7A ON THE
NEXT PAGE.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
473
T
E
S
T
S
N
O
TEST NS-7A
CONTINUED - CHECKING THE IDLE AIR CONTROL MOTOR
S
T
A
R
T
T
E
S
T
S
FIG. 1
474
TEST NS-7A
N
O
CONTINUED - CHECKING THE IDLE AIR CONTROL MOTOR
TEST NS-7A
CONTINUED FROM
THE PREVIOUS
PAGE.
REMOVE THE IDLE
AIR CONTROL MOTOR
FROM THE THROTTLE
BODY.
S
T
A
R
T
TURN IGNITION OFF.
T
E
S
T
S
RECONNECT IDLE AIR
CONTROL MOTOR
ELECTRICAL
CONNECTOR.
WITH DRB, ACTUATE
THE IDLE AIR
CONTROL MOTOR.
IS THE IDLE AIR
CONTROL MOTOR TIP
MOVING IN AND OUT?
NO
CONTINUE TEST
NS-7A ON THE
NEXT PAGE.
FIG. 1
YES
INSPECT THROTTLE
BODY FOR A
RESTRICTION OR
CARBON BUILD UP.
IS THE THROTTLE
BODY FREE OF
RESTRICTIONS?
NO
CLEAN OR REPLACE
THROTTLE BODY.*
YES
PERFORM TEST
NS-8A.
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
475
N
O
S
T
A
R
T
TEST NS-7A
CONTINUED - CHECKING THE IDLE AIR CONTROL MOTOR
TJ/XJ BODY
T
E
S
T
S
FIG. 1
476
TEST NS-7A
N
O
CONTINUED - CHECKING THE IDLE AIR CONTROL MOTOR
TEST NS-7A
CONTINUED FROM
THE PREVIOUS
PAGE.
S
T
A
R
T
KEY OFF,
DISCONNECT THE
POWERTRAIN CONTROL
MODULE.**
T
E
S
T
S
THE FOLLOWING
STEPS ARE CHECKING
FOR A SHORT
BETWEEN THE DRIVER
CIRCUITS...
USING AN OHMMETER,
MEASURE THE
RESISTANCE BETWEEN
THE ...
IAC #1 DRIVER AND
#2,#3,#4 DRIVERS.
IS THE RESISTANCE
BELOW 5.0 OHMS ON
ANY OF THE
DRIVERS?
YES
REPAIR THE IAC
DRIVER CIRCUITS,
SHORTED TOGETHER.*
YES
REPAIR THE IAC
DRIVER CIRCUITS,
SHORTED TOGETHER.*
YES
REPAIR THE IAC
DRIVER CIRCUITS,
SHORTED TOGETHER.*
FIG. 1
NO
MEASURE THE
RESISTANCE BETWEEN
THE ...
IAC #2 DRIVER AND
#3,#4 DRIVERS.
IS THE RESISTANCE
BELOW 5.0 OHMS ON
ANY OF THE
DRIVERS?
FIG. 1
NO
MEASURE THE
RESISTANCE BETWEEN
THE ...
IAC #3 DRIVER AND
#4 DRIVER.
IS THE RESISTANCE
BELOW 5.0 OHMS?
FIG. 1
NO
REPLACE THE IDLE
AIR CONTROL
MOTOR.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
477
N
O
S
T
A
R
T
TEST NS-8A
REPAIRING A START AND STALL CONDITION
Perform TEST NS-SEL Before Proceeding
NOTES
T
E
S
T
S
478
TEST NS-8A
REPAIRING A START AND STALL CONDITION
Perform TEST NS-SEL Before Proceeding
At this point in the diagnostic test procedure, you have determined that all of the engine electrical
systems are operating as designed; therefore, they are not the cause of the start and stall
problem. The following additional items should be checked as possible mechanical causes of the
no start condition. Any one or more of these items can produce a no start condition; none can be
overlooked as a possible cause.
1. DISTRIBUTOR POSITION — must be within specifications*
2. ENGINE VALVE TIMING — must be within specifications
3. ENGINE COMPRESSION — must be within specifications
4. ENGINE EXHAUST — must be free of any restrictions
5. ENGINE PCV SYSTEM — must flow freely
6. ENGINE DRIVE SPROCKETS — must be properly positioned
7. FUEL — must be free of contamination
8. ENGINE SECONDARY IGNITION CHECK — must exhibit a normal scope pattern
Always look for any Technical Service Bulletins that may relate to this condition.
Checking Distributor Position With DRBIIIT
Connect the DRB to the Data Link Connector and select the set SYNC from the menu.
WARNING: The following test will be performed with the engine running: avoid contact with
rotating components.
Start the engine and observe the DRB display. When the distributor is correctly positioned, the IN
RANGE message should appear along with 0°. If the distributor needs to be adjusted, loosen the
distributor hold-down clamp bolt. Rotate the distributor until reading is as close to 0° as possible and
the IN RANGE message is displayed. Tighten the clamp bolt to 22.5 N·m (200 in. lbs.) torque.
NOTE: Setting the distributor position does not adjust the ignition timing. Ignition timing values are
determined by the powertrain control module.
479
N
O
S
T
A
R
T
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-9A
REPAIRING A NO CRANK CONDITION
Perform TEST NS-SEL Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
480
TEST NS-9A
N
O
REPAIRING A NO CRANK CONDITION
Perform TEST NS-SEL Before Proceeding
IS THE VEHICLE
EQUIPPED WITH A
MANUAL
TRANSMISSION?
START TEST
NS-9A.
YES
PERFORM TEST
NS-9B.
T
E
S
T
S
NO
ENSURE THE
TRANSMISSION IS IN
PARK.
WITH DRB, SELECT
INPUTS/OUTPUTS.
READ PARK/NEUTRAL
POSITION.
DOES THE DRB READ
P/N?
NO
NOTE: THE
PARK/NEUTRAL
SWITCH SENSE
CIRCUIT IS OPEN.
YES
PERFORM TEST
TC-114.
DISCONNECT THE
STARTER RELAY
CONNECTOR.**
WITH A VOLTMETER,
MEASURE THE FUSED
B(+) CIRCUIT AT
THE STARTER RELAY.
FIG. 1 OR 2
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR OPEN FUSED
B(+) CIRCUIT.*
NO
REPAIR OPEN
IGNITION SWITCH
OUTPUT CKT.*
YES
MEASURE THE
IGNITION SWITCH
OUTPUT CIRCUIT AT
THE STARTER RELAY
CONN. FIG. 1 OR 2
WHILE OBSERVING
VOLTMETER, HOLD
IGNITION KEY IN
THE START
POSITION.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
YES
WARNING: KEY OFF.
THE TRANS MUST BE IN
PARK AND THE PARKING
BRAKE MUST BE ON FOR
THE NEXT STEP.
WARNING: THE ENGINE
MAY BE CRANKED IN
THE NEXT STEP. KEEP
AWAY FROM MOVING
ENGINE PARTS.
*Perform Verification TEST VER-1A.
BRIEFLY CONNECT A
JUMPER WIRE BETWEEN
STARTER RLY FUSED
(B+) & OUTPUT CKTS.
FIG. 1 OR 2
PERFORM TEST
NS-9C.
**Check connectors - Clean / repair as necessary.
481
S
T
A
R
T
N
O
S
T
A
R
T
TEST NS-9B
REPAIRING A NO CRANK CONDITION
Perform TEST NS-9A Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
482
TEST NS-9B
N
O
REPAIRING A NO CRANK CONDITION
Perform TEST NS-9A Before Proceeding
START TEST
NS-9B.
S
T
A
R
T
DISCONNECT THE
STARTER RELAY.**
WITH AN OHMMETER,
MEASURE THE
STARTER RELAY P/N
SENSE CIRCUIT.
FIG. 1 OR 2
IS THE RESISTANCE
ABOVE 5.0 OHMS?
YES
REPAIR THE OPEN
STARTER RELAY
GROUND CIRCUIT.*
NO
WITH A VOLTMETER,
MEASURE THE FUSED
B(+) CIRCUIT.
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
NO
REPAIR OPEN FUSED
B(+) CIRCUIT.*
NO
REPAIR OPEN
IGNITION SWITCH
OUTPUT CKT.*
FIG. 1 OR 2
YES
WITH A VOLTMETER,
MEASURE THE
IGNITION SWITCH
OUTPUT CIRCUIT.
FIG. 1 OR 2
WHILE OBSERVING
VOLTMETER, HOLD
IGNITION KEY IN THE
RUN POSITION AND
DEPRESS CLUTCH PEDAL
IS THE VOLTAGE
ABOVE 10.0 VOLTS?
YES
WARNING: THE TRANS
MUST BE IN NEUTRAL
AND THE PARKING
BRAKE MUST BE ON
FOR THE NEXT STEP.
KEY OFF.
WARNING: THE ENGINE
MAY BE CRANKED IN
THE NEXT STEP. KEEP
AWAY FROM MOVING
ENGINE PARTS.
BRIEFLY CONNECT A
JUMPER WIRE BETWEEN
STARTER RLY B(+) AND
OUTPUT CKTS.
FIG. 1 OR 2
*Perform Verification TEST VER-1A.
PERFORM TEST
NS-9C.
**Check connectors - Clean / repair as necessary.
483
T
E
S
T
S
N
O
S
T
A
R
T
TEST NS-9C
REPAIRING A NO CRANK CONDITION
Perform TEST NS-9A Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
484
TEST NS-9C
N
O
REPAIRING A NO CRANK CONDITION
Perform TEST NS-9A Before Proceeding
START TEST
NS-9C.
DID THE STARTER
MOTOR CRANK THE
ENGINE?
YES
CONTINUE TEST
NS-9C ON THE
NEXT PAGE.
T
E
S
T
S
NO
NOTE IF THE
STARTER SOLENOID
CLICKED WHEN THE
JUMPER WIRE WAS
CONNECTED.
DISCONNECT STARTER
RELAY OUTPUT WIRE
FROM THE STARTER
SOLENOID.**
MEASURE THE
RESISTANCE OF THE
STARTER RELAY
OUTPUT CIRCUIT...
DISCONNECT THE
JUMPER WIRE.
USE AN OHMMETER IN
THE FOLLOWING
STEP.
FROM THE RELAY TO
THE SOLENOID
CONNECTOR.
IS THE RESISTANCE
BELOW 5.O OHMS?
NO
REPAIR OPEN
STARTER RELAY
OUTPUT CKT.*
FIG. 1 OR 2
YES
REINSTALL STARTER
RELAY.
CHECK THE BATTERY
CABLES FOR HIGH
RESISTANCE.(USE
SERVICE MANUAL
PROCECURE)
DID EITHER BATTERY
CIRCUIT HAVE A
VOLTAGE DROP
GREATER THAT 0.2
VOLT?
YES
REPAIR THE BATTERY
CIRCUIT FOR HIGH
RESISTANCE.*
NO
REPLACE THE
STARTER SOLENOID.*
NO
DID THE STARTER
SOLENOID CLICK WHEN
THE JUMPER WIRE WAS
PREVIOUSLY
CONNECTED?
YES
REPAIR MECHANICAL
CONDITION
PREVENTING THE
STARTER MOTOR FROM
CRANKING.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
485
S
T
A
R
T
N
O
S
T
A
R
T
TEST NS-9C
CONTINUED - REPARING A NO CRANK CONDITION
Perform TEST NS-9A Before Proceeding
TJ BODY
T
E
S
T
S
FIG. 1
XJ BODY
FIG. 2
486
TEST NS-9C
N
O
CONTINUED - REPARING A NO CRANK CONDITION
Perform TEST NS-9A Before Proceeding
TEST NS-9C
CONTINUED FROM
THE PREVIOUS
PAGE.
IS THE VEHICLE
EQUIPPED WITH AN
MANUAL
TRANSMISSION?
S
T
A
R
T
YES
NO
WITH AN OHMMETER,
MEASURE THE P/N
POSITION SWITCH
SENSE CIRCUIT...
IN THE STARTER
RELAY CONNECTOR.
IS THE RESISTANCE
BELOW 5.0 OHMS?
YES
REPLACE THE
STARTER RELAY.*
FIG. 1 OR 2
NO
REPAIR THE OPEN
PARK/NEUTRAL SWITCH
SENSE CIRCUIT
BETWEEN STARTER
RELAY AND SPLICE.*
*Perform Verification TEST VER-1A.
**Check connectors - Clean / repair as necessary.
487
T
E
S
T
S
V TEST VER-1A NO START VERIFICATION
E
R
I
F Important Note:
I
C If the Powertrain Control Module has been changed and the correct VIN and mileage have not been
A programmed, a DTC will be set in the ABS, Airbag and SKIM modules. In addition, if the vehicle is
T equipped with a Sentry Key Immobilizer Module (SKIM), Secret Key data must be updated to enable
I starting. Refer to GENERAL INFORMATION section 8.0 for programming the Powertrain Control
O Module and the SKIM.
N For ABS and Airbag Systems:
T
E
S
T
ACTION:
1. Enter correct VIN and Mileage in PCM.
2. Erase codes in ABS and Airbag modules.
Inspect the vehicle to ensure that all engine components are connected. Reassemble and reconnect
components as necessary.
Inspect the engine oil for contamination. If it is contaminated, change the oil and filter.
Attempt to start the engine.
If the engine is unable to start, look for any Technical Service Bulletins that may relate to this
condition. Return to DTC TEST if necessary.
The repair is now complete.
488
TEST VER-2A
ROAD TEST VERIFICATION
Important Note:
Inspect the vehicle to ensure that all engine components are connected. Reassemble and reconnect
all components as necessary.
Important Note:
If the Powertrain Control Module has been changed and the correct VIN and mileage have not been
programmed, a DTC will be set in the ABS, Airbag and SKIM modules. In addition, if the vehicle is
equipped with a Sentry Key Immobilizer Module (SKIM), Secret Key data must be updated to enable
starting. Refer to GENERAL INFORMATION section 8.0 for programming the Powertrain Control
Module and SKIM.
For ABS and Airbag Systems:
ACTION:
1. Enter the correct VIN and Mileage in PCM.
2. Erase ABS and Airbag module codes.
All trouble codes should be repaired before continuing, if not, return DTC-TEST and follow
suggested test.
Use the following methods depending on the type of test you came from, No Trouble Code, or
Trouble Code.
•
Connect the DRBIII to the data link connector.
No Trouble Code Repair
1. Check to see if the initial symptom still exists (use DRB freeze frame when available to assist).
2. If the initial or another symptom exists, or a Trouble Code Set, repairs are not complete. Check
all pertinent Technical Service Bulletins and return to TEST NTC-1A, or for codes return to
DTC-TEST.
489
V
E
R
I
F
I
C
A
T
I
O
N
T
E
S
T
V TEST VER-2A ROAD TEST VERIFICATION
E
R
I
F Inspect the vehicle to ensure that all engine components are connected. Reassemble and reconnect
I all components as necessary.
C
A For previously read trouble codes that have not been dealt with, return to DTC TEST and follow the
T path specified; otherwise continue.
I If the powertrain control module has not been changed:
O
N
1. Connect the DRB to the PCM data link connector and erase trouble codes.
T
E
S
T
2. With the DRB, reset all values in the adaptive memory.
3. Disconnect the DRB.
Ensure no trouble code remains by doing the following:
1. If this test is for any A/C Relay Control Circuit Code, drive the vehicle for at least five minutes
with the A/C on. For some of the drive, go at least 40 mph; at some point stop the car and turn
the engine off for 10 seconds or more; then restart and continue. Ensure the transmission shifts
through all gears. Upon completion of the road test, turn the engine off, and read trouble codes
with the DRB.
2. If the repaired code has reset, the repair is not complete. Check all related Technical Service
Bulletins and return to DTC TEST if necessary. If another trouble code has set, return to DTC
TEST and follow the path specified for that trouble code. If there are no trouble codes, the
repair was successful and is now complete.
490
TEST VER-3A
CHARGING VERIFICATION
Important Note:
If the Powertrain Control Module has been changed and the correct VIN and mileage have not been
programmed, a DTC will be set in the ABS, Airbag and SKIM modules. In addition, if the vehicle is
equipped with a Sentry Key Immobilizer Module (SKIM), Secret Key data must be updated to enable
starting. Refer to GENERAL INFORMATION section 8.0 for programming the Powertrain Control
Module and SKIM.
Inspect the vehicle to ensure that all engine components are connected. Reassemble and reconnect
components as necessary.
If the powertrain control module has been changed, do the following:
1. If the vehicle is equipped with a factory theft alarm, start the vehicle at least 20 times so that
the alarm system may be activated when desired.
Connect the DRB to the PCM data link connector and erase the codes.
Ensure no other charging system problems remain by doing the following:
1. Start the engine.
2. Raise the engine speed to 2000 rpm for at least 30 seconds.
3. Allow the engine to idle.
4. Turn the engine off.
5. Turn the ignition key on.
6. With the DRB, read trouble code messages.
If the repaired code as reset, or another one has set, check all pertinent Technical Service Bulletins
and return to DTC TEST if necessary.
If there are no codes, the repair is now complete.
491
V
E
R
I
F
I
C
A
T
I
O
N
T
E
S
T
V TEST VER-4A SPEED CONTROL VERIFICATION
E
R
I Important Note:
F If the Powertrain Control Module has been changed and the correct VIN and mileage have not been
I programmed, a DTC will be set in the ABS, Airbag and SKIM modules. In addition, if the vehicle is
C equipped with a Sentry Key Immobilizer Module (SKIM), Secret Key data must be updated to enable
A starting. Refer to GENERAL INFORMATION section 8.0 for programming the Powertrain Control
T Module and SKIM.
I
O For ABS and Airbag Systems:
N ACTION:
T
E
S
T
1. Enter correct VIN and Mileage in PCM.
2. Erase codes in ABS and Airbag modules.
Inspect the vehicle to ensure that all engine components are connected. Reassemble and reconnect
components as necessary.
Connect the DRB to the PCM data link connector and erase the codes.
Ensure no other speed control problems remain by doing the following:
1. Road test the vehicle at a speed above 30 mph.
2. Turn the speed control ON/OFF switch to the ON position.
3. Depress and release the SET switch. If the speed control did not engage, the repair is not
complete.*
4. Quickly depress and release the RESUME/ACCEL switch. If the vehicle speed did not increase
by 2 mph, the repair is not complete.*
5. Press and HOLD coast switch, vehicle speed should decrease, if no decrease, the repair is not
complete.*
6. Using caution, depress and release the brake pedal. If the speed control did not disengage, the
repair is not complete.*
7. Bring the vehicle speed back up to 25 mph.
8. Depress the RESUME/ACCEL switch. If the speed control did not resume the previously set
speed, the repair is not complete.*
9. Hold down the SET switch. If the vehicle did not decelerate, the repair is not complete.*
10. Ensure the vehicle speed is greater than 30 mph and release the SET switch. If the vehicle did
not adjust and set a new vehicle speed, the repair is not complete.*
11. Depress and release the cancel switch. If the speed control did not disengage, the repair is not
complete.*
12. Bring the vehicle back up to 35 mph and engage speed control.
13. Turn the ON/OFF switch to the OFF position. If the speed control did not disengage, the repair
is not complete.*
If the vehicle successfully passed all of the previous tests, the speed control system is now
functioning as designed. The repair is now complete.
*Check for Technical Service Bulletins that pertain to speed control problem and then, if necessary,
return to DTC TEST.
492
8.0
MAINTENANCE AND SERVICE INFORMATION
8.1
Programming the Powertrain Control Module
The SKIS ‘‘Secret Key’’ is an I.D. code that is unique to each SKIM. This code is programmed and
stored in the SKIM, engine controller and transponder chip (ignition keys). When replacing the
PCM it is necessary to program the secret key into the new PCM using the DRB. Perform the
following steps to program the secret key into the engine controller.
1. Turn the ignition on (transmission in park/neutral)
2. Use the DRB and select ‘‘MISCELLANEOUS’’ from the main menu.
3. Select ‘‘PCM REPLACED’’ (GAS ENGINE).
4. Enter secured access mode by entering the vehicle four-digit PIN.
NOTE: If three attempts are made to enter secure access mode using an incorrect PIN, secured
access mode will be locked out for one hour. To exit this lockout mode, turn the ignition to the RUN
position for one hour then enter the correct PIN. (Ensure all accessories are turned off. Also
monitor the battery state and connect a battery charger if necessary).
5. Press ‘‘ENTER’’ to transfer the secret key (the SKIM will send the secret key to the PCM).
8.2
Programming the Sentry Key Immobilizer Module
NOTE: If the PCM and the SKIM are replaced at the same time, program the VIN into the PCM
first. All vehicle keys will need to be replaced and programmed to the new SKIM.
1. Turn the ignition on (transmission in park/neutral).
2. Use the DRB and select ‘‘THEFT ALARM’’, ‘‘SKIM’’, ‘‘MISCELLANEOUS’’.
4. Program the vehicle four-digit PIN into SKIM.
5. Select ‘‘COUNTRY CODE’’ and enter the correct country.
NOTE: Be sure to enter the correct country code. If the incorrect country code is programmed into
SKIM, the SKIM must be replaced.
6. Select ‘‘UPDATE VIN’’ (the skim will learn the VIN from the PCM).
7. Press ‘‘ENTER’’ to transfer the secret key (the PCM will send the secret key to the SKIM).
8. Program ignition keys to SKIM (for programming procedure, refer to GENERAL INFORMATION SECTION 8.3).
8.3
Programming Ignition Keys to the Sentry Key Immobilizer Module
1. Turn the ignition on (transmission in park/neutral).
2. Use the DRB and select ‘‘THEFT ALARM’’, ‘‘SKIM’’, ‘‘MISCELLANEOUS’’.
3. Select ‘‘PROGRAM IGNITION KEYS’’ (Indicator lamp will begin flashing to indicate that learn
mode is in progress.
4. Enter secured access mode by entering the vehicle four-digit PIN
NOTE: The PIN must be re-entered each time an additional key is learned.
5. Insert key into ignition switch and observe ALARM SET lamp. Once the key has been learned,
the ALARM SET lamp will turn off.
493
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
NOTE: A maximum of eight keys can be learned to each SKIM. Once a key is learned to a SKIM
it (the key) cannot be transferred to another vehicle.
If ignition key programming is unsuccessful, the DRB will display one of the following messages:
Programming Not Attempted − The DRB attempts to read the programmed key status and there
are no keys programmed into SKIM memory.
Programming Key Failed (Possible Used Key From Wrong Vehicle − SKIM is unable to program
key due to one of the following:
–
faulty ignition key transponder
–
ignition key is programmed to another vehicle.
8 Keys Already Learned, Programming Not Done − SKIM transponder ID memory is full.
1. Obtain ignition keys to be programmed from customer (8 keys maximum)
2. Using the DRB, erase all ignition keys by selecting ‘‘MISCELLANEOUS’’ and ‘‘ERASE ALL
CURRENT IGN. KEYS’’
3. Program all ignition keys.
Learned Key In Ignition − Ignition key transponder ID is currently programmed in SKIM memory.
9.0
SPECIFICATIONS
9.1
Fuel System Release Procedure (Gasoline)
1. Remove the fuel pump relay.
2. Start and run engine until it stalls.
3. Attempt to restart the engine until it will no longer run.
4. Ensure the ignition key is off.
5. With fuel pressure relieved the fuel system can now be opened for required work. Continue
to use caution, fuel leakage is still possible.
494
10.0
SCHEMATIC DIAGRAMS
10.1
TJ Body 2.5/4.0L JTEC+
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
495
G
E
N
E
R
A
L
10.2
XJ Body 2.5L JTEC+
I
N
F
O
R
M
A
T
I
O
N
496
10.3
G
E
N
E
R
A
L
XJ Body 4.0 JTEC+
I
N
F
O
R
M
A
T
I
O
N
497
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
11.0
RECOMMENDED TOOLS AND EQUIPMENT
DRBIIIT (diagnostic read-out box)
fuel line adapter 6523, 6539 or 6941
fuel pressure test kit C-4799-B or 5069
jumper wires
ohmmeter
oscilloscope
vacuum gauge
voltmeter
pressure gauge (0-300 psi)
12.0
GLOSSARY OF TERMS
backfire,
popback
fuel ignites in either the intake or the exhaust system.
CKP
crank position sensor
CMP
camshaft position sensor
cuts out,
misses
a steady pulsation or the inability of the engine to maintain a consistent
rpm
DLC
data link connector (previously called ‘‘engine diagnostic connector’’)
detonation,
spark knock
a mild to severe ping, especially under loaded engine conditions
ECT
engine coolant temperature sensor
EGR
exhaust gas recirculation valve and system
generator
previously called ‘‘alternator’’
hard start
The engine takes longer than usual to start, even though it is able to
crank normally.
hesitation,
sag, stuble
There is a momentary lack of response when the throttle is opened.
This can occur at all vehicle speeds. If it is severe enough, the engine
may stall.
IAT
intake air temperature sensor
JTEC+
Combined engine and transmission control module
lack of
power,
sluggish
The engine has less than expected power, with little or no increase in
vehicle speed
when the throttle is opened.
MAP
manifold absolute pressure sensor
MTV
manifold tuning valve
MVLPS
manual valve lever position switch (previously called ‘‘park/neutral
switch’’)
498
O2S
oxygen sensor (left oxygen sensor when there are two sensors)
O2SR
right oxygen sensor
PCM
powertrain control module
PCV
positive crankshaft ventilation
poor fuel
economy
There is significantly less fuel mileage than other vehicles of the same
design
and configuration.
rough,
unstable
erratic
idle
stalling
The engine runs unevenly at idle and causes the engine to shake if it is
severe enough. The engine idle rpm may vary (called ‘‘hunting’’). This
condition may cause stalling if it is severe enough.
start &
stall
The engine starts but immediately dies.
SKIS
Sentry Key Immobilizer System
surge
engine rpm fluctuation without corresponding change in throttle position
sensor
TPS
throttle position sensor
VSS
vehicle speed sensor
499
G
E
N
E
R
A
L
I
N
F
O
R
M
A
T
I
O
N
G
E
N
E
R
A
L
NOTES
I
N
F
O
R
M
A
T
I
O
N
500