Download Troubleshooting Withvolt Ohmmet

EFI SYSTEM
−
FI−29
Troubleshooting with Volt Ohmmeter
TROUBLESHOOTING WITH
VOLT OHMMETER
HINT: The following troubleshooting procedures
are designed for inspection of each separate sys−
tem, and therefore the actual procedure may vary
somewhat. However, troubleshooting should be
performed referring to the inspection methods de−
scribed in this manual.
Before beginning inspection, it is best to first make
a simple check of the fuses, fusible links
and condition of the connectors.
The following troubleshooting procedures are
based on the supposition that the trouble lies in
either a short or open circuit in a component out
side the computer or a short circuit within the
computer.
If engine trouble occurs even though proper
operating voltage is detected in the computer
connector, then it can be assumed that the engine
ECU is faulty and should be replaced.
LOCATION OF FUSES AND FUSIBLE LINK
K
CISCO IDS PAR
TS
PR
CT
JE
O
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−30
EFI SYSTEM
−
Troubleshooting with Volt Ohmmeter
EFI SYSTEM CHECK PROCEDURE
PREPARATION
(a) Disconnect the connectors from the engine and ECT
ECU.
(b) Remove the locks as shown in the illustration so
that the tester probe(s) can easily come in.
NOTICE: Pay attention to sections ”A” and ”B” in the
illustration which can be easily broken.
(c) Reconnect the connectors to the engine and ECT
ECU.
HINT:
•
Perform all voltage measurements with the connectors
connected.
•
Verify that the battery voltage is 11 V or more when
the ignition switch is in the ”ON” position.
Using a voltmeter with high impedance (10 kW/v minimum),
measure the voltage at each terminal of the wiring
connectors.
Terminals of Engine and ECT ECU
Symbol
Terminal Name
Symbol
Terminal Name
Symbol
Terminal Name
E01
POWER GROUND
DISTRIBUTOR
A/C
A/C COMPRESSOR
E02
POWER GROUND
DISTRIBUTOR
OD1
CRUISE CONTROL COMPUTER
INJECTOR (No. 1 and 6)
DISTRIBUTOR
SP1
NO. 1 SPEED SENSOR (Meter side)
No. 30
INJECTOR (No.4 and 5)
COMPUTER GROUND
OD2
OD MAIN SWITCH
No. 20
INJECTOR (No.2 and 3)
CHECK CONNECTOR
SP2
No. 10
NO.2 SPEED SENSOR (A/T side)
STJ
COLD START INJECTOR
G(−)
DISTRIBUTOR
EGR
VSV(EGR)
TE2
TDCL
TDCL
TE1
CHECK CONNECTOR,TDCL
TEMS ECU
ox1
OXYGEN SENSOR
KNK
KNOCK SENSOR
TEMS ECU
*ox2
SUB−OXYGEN SENSOR
WARNING LIGHT
*HT
OXYGEN SENSOR HEATER
A/D
CRUISE CONTROL COMPUTER
STP
STOP LIGHT SWITCH
ISC1
ISC MOTOR NO. 1 COIL
THW
WATER TEMP. SENSOR
IGNITER
ISC2
ISC MOTOR NO. 2 COIL
ECT SOLENOID
ISC 3
SHIFT POSITION SWITCH
M−REL
EFI MAIN RELAY (COIL)
SHIFT POSITION SWITCH
THA
AIR TEMP. SENSOR
SHIFT POSITION SWITCH
VTA
THROTTLE POSITION SENSOR
AIR FLOW METER
*THG
SHIFT POSITION SWITCH
IGNITION SWITCH
K
CISCO IDS PAR
EFI MAIN RELAY
TS
BATT
BATTERY
IGNITER
STA
STARTER SWITCH
+B1
EFI MAIN RELAY
HEAD LIGHT RELAY,
DEFOGGER RELAY
NSW
NEUTRAL START SWITCH
PR
CT
JE
O
IG SW
EGR GAS TEMP. SENSOR
AIR FLOW METER,
THROTTLE POSITION SENSOR
SENSOR GROUND
ISC MOTOR NO. 4 COIL
ECT SOLENOID
ELS
FUEL PUMP RELAY
THROTTLE POSITION SENSOR
ISC MOTOR NO. 3 COIL
ECT SOLENOID
ISC4
IDL
FPR
.CISCOKIDS.C
WW
O
M
W
.A
U
IGT
TEMS ECU
EFI SYSTEM
−
FI−31
Troubleshooting with Volt Ohmmeter
Voltage at Engine and ECT ECU Wiring
Connectors
Condition
Terminals
STD Voltage
See page
FI−32
Ignition SW ON
FI−33
FI−34
Ignition SW ON
Throttle valve open
FI−3 5
Throttle valve fully closed
FI−36
Throttle valve fully open
Ignition SW ON
Measuring plate fully closed
Measuring plate fully open
FI−37
Idling
3,000 rpm
Ignition SW ON
FI−38
Ignition SW ON
Intake air temperature 20°C (68°F)
FI−39
Ignition SW ON
Coolant temperature 80°C (176°F)
FI−40
Cranking
FI−41
Idling
FI−42
Ignition SW ON
FI−43
No trouble (”CHECK” engine warning light off) and engine
running
Ignition SW ON
Air conditioning ON
FI−44
FI−45
K
CISCO IDS PAR
TS
PR
CT
JE
O
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
FI−32
Terminals
Trouble
−
Troubleshooting with Volt Ohmmeter
Condition
STD Voltage
No voltage
No voltage
Ignition switch ON
No voltage
Ignition switch ON
No voltage
Ignition switch ON
• BATT − E1
There is no voltage between ECU terminals BATT and E1.
Check that there is voltage between ECU terminal BATT and
body ground.
Check wiring between ECU terminal El. and body
ground.
BAD
Repair or replace.
Try another ECU.
Check fuse and fusible link.
BAD
Replace.
K
CISCO IDS PAR
TS
PR
Repair or replace.
CT
JE
O
Check wiring between ECU
terminal and battery.
BAD
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
EFI SYSTEM
EFI SYSTEM
−
FI−33
Troubleshooting with Volt Ohmmeter
• IG SW − E1
There is no voltage between ECU terminals IG SW and E1.
(IG SW ON)
Check that there is voltage between ECU terminal IG SW and
body ground. (IG SW ON)
Check wiring between ECU terminal E1 and ground.
BAD
Try another ECU.
Check fuse, fusible link and
ignition switch.
Repair or replace.
BAD
Repair or replace.
• M−REL − E1
There is no voltage between ECU terminals M−REL and E1.
(IG SW ON)
Check that there is voltage between ECU terminal M−REL and
body ground. (IG SW ON)
Check wiring between ECU terminal E1 and ground.
BAD
Try another ECU.
Check EFI main relay and wiring
harness.
Repair or replace.
BAD
Replace.
K
CISCO IDS PAR
TS
CT
JE
O
Try another ECU.
PR
.CISCOKIDS.C
WW
O
M
W
.A
U
EFI SYSTEM
−
Troubleshooting with Volt Ohmmeter
• +B (+B1) − E1
There is no voltage between ECU terminals + B (+ B1) and
E1. (IG SW ON)
Check that there is voltage between ECU terminal +B (+ B1)
and body ground. (IG SW ON)
Check wiring between ECU terminal E1 and ground.
BAD
Try another ECU.
Repair or replace.
Check fuse, fusible link and wiring
harness.
BAD
Check EFI main relay.
(See page FI−76)
BAD
Repair or replace.
Replace.
Refer to M−REL − E1 trouble
section.
K
CISCO IDS PAR
TS
PR
CT
JE
O
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−34
EFI SYSTEM
Terminals
FI−35
Troubleshooting with Volt Ohmmeter
STD Voltage
Condition
Trouble
Throttle valve open
No voltage
Ignition
SW ON
Throttle valve fully closed
Throttle valve fully open
• IDL − E2
There is no voltage between ECU terminals IDL and E2.
(IG SW ON) (Throttle valve open)
Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)
Check wiring between ECU terminal E1 and body
ground.
BAD
Repair or replace.
Try another ECU.
Refer to No.1.
(See page FI−34)
Check throttle position sensor.
BAD
Repair or replace.
K
CISCO IDS PAR
T
BAD S
Repair or replace throttle
position sensor.
Check wiring between ECU
and throttle position sensor.
Try another ECU.
PR
CT
JE
O
BAD
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
−
EFI SYSTEM
−
Troubleshooting with Volt Ohmmeter
• VC −E2
There is no voltage between ECU terminals VC and E2.
(IG SW ON)
Check that there is voltage between ECU terminal + B
(+ B1) and body ground. (IG SW ON)
Refer to No. 1.
(See page FI−34)
Check throttle position
sensor. (See page FI−68)
BAD
Repair or replace.
Check wiring between ECU and throttle
position sensor.
BAD
Repair or replace
wiring.
Try another ECU.
• VTA−E2
There is no voltage at ECU terminals VTA and E2.
(IG SW ON)
Check that there is voltage between ECU terminals VC and
E2. (IG SW ON)
Refer to VC − E2 trouble
section.
(3) Check throttle position sensor.
Check wiring between ECU and
throttle position sensor.
BAD
BAD
Repair or replace.
Repair or replace.
K
CISCO IDS PAR
TS
PR
CT
JE
O
Try another ECU.
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−36
EFI SYSTEM
Terminals
Trouble
STD Voltage
Condition
Ignition
SW ON
FI−37
Troubleshooting with Volt Ohmmeter
Measuring plate fully closed
Measuring plate fully open
No voltage
Idling
3,000 rpm
There is no voltage between ECU terminals VC or VS and E2.
(IG SW ON)
Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)
Refer to No. 1.
(See page FI−34)
Check wiring between ECU terminal E1 and body ground.
BAD
Check air flow meter.
(See page FI−66)
BAD
K
CISCO IDS PAR
TS
Check wiring between ECU and air
flow meter.
BAD
Try another ECU.
Repair or replace.
PR
CT
JE
O
Replace air flow
meter.
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
−
No.
EFI SYSTEM
Terminals
−
Troubleshooting with Volt Ohmmeter
Trouble
Condition
No voltage
Ignition SW ON
STD Voltage
There is no voltage between ECU terminals No. 10, No. 20
and/or No.30 and E01 and/or E02. (IG SW ON)
Check that there is voltage between ECU terminal No. 10,
No.20 and/or No.30 and body ground.
Check wiring between ECU terminal E01 and/or E02
and body ground.
BAD
Repair or replace.
Try another ECU.
Check fusible links and ignition
switch.
BAD
Repair or replace.
K
CISCO IDS PAR
TS
PR
CT
JE
O
Check resistance of magnetic coil in each injector.
STD resistance: Approx. 13.8 Ω
BAD
Replace injector.
Check wiring between ECU terminal No. BAD
10, No. 20 and/or No. 30 and battery.
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−38
EFI SYSTEM
Terminals
Trouble
No voltage
STD Voltage
Condition
Ignition
SW ON
FI−39
Troubleshooting with Volt Ohmmeter
Intake air temperature 20°C
(68_F)
There is no voltage between ECU terminals THA and E2.
(IG SW ON)
Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)
Refer to No. 1.
(See page FI−34)
Check wiring between ECU terminal E1 and body ground.
BAD
Check air temp. sensor.
(See page FI−66)
BAD
K
CISCO IDS PAR
TS
Check wiring between ECU and air
temp. meter.
BAD
Try another ECU.
Repair or replace.
PR
CT
JE
O
Replace air flow
meter.
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
−
No.
EFI SYSTEM
Terminals
−
Trouble
No voltage
Troubleshooting with Volt Ohmmeter
Condition
Ignition
SW ON
STD Voltage
Coolant temperature 80°C
(176°F)
There is no voltage between ECU terminals THW and E2.
(IG SW ON)
Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)
Refer to No. 1.
(See page FI−34)
Check wiring between ECU terminal E1 and body ground.
BAD
Check water temp. sensor.
(See page FI−78)
BAD
K
CISCO IDS PAR
TS
Check wiring between ECU and water
temp. sensor.
PR
BAD
Try another ECU.
Repair or replace.
CT
JE
O
Replace water
temp. sensor.
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−40
EFI SYSTEM
Terminals
FI−41
Troubleshooting with Volt Ohmmeter
Trouble
Condition
No voltage
Cranking
STD Voltage
There is no voltage between ECU terminals STA and E1.
(IG SW START)
Check starter
operation.
Check wiring between ECU terminal STA
and ignition switch terminal ST1.
BAD
BAD
Repair or replace.
Check wiring between ECU terminal E1 and body
ground.
BAD
Repair or replace.
Try another ECU.
Check fusible link, battery, wiring,
ignition switch and neutral start
switch.
BAD
Repair or replace.
K
CISCO IDS PAR
TS
Check starter.
Check wiring between ignition switch
terminal ST1 and starter terminal 50.
PR
CT
JE
O
Check that there is voltage at STA (50) terminal of starter.
(IG SW START) STD voltage: 6 − 14 V
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
−
No.
EFI SYSTEM
Terminals
−
Troubleshooting with Volt Ohmmeter
Trouble
Condition
No voltage
Idling
STD Voltage
There is no voltage between ECU terminals IGT and E1.
(Idling)
Check that there is voltage between ECU terminal IGT
and body ground. (Idling)
Check wiring between ECU
terminal E1 and body ground.
BAD
Repair or
replace.
Try another ECU.
Check fusible link and ignition
switch.
Check wiring between ECU and
battery.
Check igniter.
BAD
Repair or replace.
K
CISCO IDS PAR
TS
P
Repair or replace.R
CT
JE
O
Check distributor. (See page IG−8)
BAD
BAD
BAD
Repair or replace.
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−42
EFI SYSTEM
Terminals
FI−43
Troubleshooting with Volt Ohmmeter
Trouble
Condition
No voltage
Ignition SW ON
STD Voltage
There is no voltage between ECU terminals ISC1 − ISC4
and E1. (IG SW ON)
Check that there is voltage between ECU terminal +B (+B1)
and body ground. (IG SW ON)
Refer to No. 1.
(See page FI−34)
Check wiring between ECU terminal E1 and body ground.
BAD
Check ISV valve.
(See page FI−73)
BAD
K
CISCO IDS PAR
TS
Check wiring between ECU and EFI PR
main relay.
BAD
Try another ECU.
Repair or replace.
CT
JE
O
Replace ISC
valve.
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
−
No.
EFI SYSTEM
Terminals
−
Troubleshooting with Volt Ohmmeter
Trouble
Condition
No voltage
No trouble (””CHECK” engine warning
light off) and engine running
STD Voltage
There is no voltage between ECU terminals W and E1.
(Idling)
Check that there is voltage between ECU terminal W and
body ground.
Check wiring between ECU terminal E1 and body
ground.
BAD
Repair or Replace.
Try another ECU.
Check GAUGE fuse (7.5 A) and ”CHECK”
engine warning light.
K
CISCO IDS PAR
TS
BAD
PR
CT
JE
O
Repair or replace.
Fuse blows again
Check wiring between ECU terminal W
and fuse.
BAD
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−44
EFI SYSTEM
Terminals
Trouble
No voltage
STD Voltage
Condition
Ignition
SW ON
FI−45
Troubleshooting with Volt Ohmmeter
Air conditioning ON
There is no voltage between ECU terminals A/C and E1.
(Air conditioning ON)
Check that there is voltage between ECU terminal A/C and
body ground.
Check wiring between ECU terminal E1 and body
ground.
BAD
Repair or replace.
Try another ECU.
Check wiring
between ECU
terminal A/C and
amplifier.
Check compressor running.
K
CISCO IDS PAR
BAD TS
BAD
Check that there is voltage between
amplifier terminal and body ground.
BAD
Check wiring between amplifier and
ECU or compressor.
BAD
Repair or replace.
Repair or replace.
PR
CT
JE
O
Repair or replace.
.CISCOKIDS.C
WW
O
M
W
.A
U
No.
−
EFI SYSTEM
−
Troubleshooting with Volt Ohmmeter
(1) There is no voltage between ECU terminals VF and E1.
Check that there is specified voltage between ECU terminal VF and
body ground.
Check wiring between ECU terminal E1 and body ground.
BAD
Repair or replace.
Try another ECU.
Check for suction of air into exhaust system.
BAD
BAD
Check for air leak from air intake system.
BAD
Check spark plugs.
BAD
Check distributor and ignition system.
BAD
Check fuel pressure.
Repair air leak.
Repair or replace.
Repair or replace.
Repair or replace.
BAD
Check injectors.
COKIDSorPreplace.
CISRepair
AR
TS
PR
BAD
Check cold start injector.*
BAD
Check operation of oxygen sensors.
CT
JE
O
Repair or replace.
Check air flow meter.
Repair or replace.
System normal.
BAD
Check wiring between oxygen sensors and
ECU connectors.
Repair oxygen sensors.
Repair air suction.
BAD
Repair wiring.
* Rich malfunction
only.
.CISCOKIDS.C
WW
O
M
W
.A
U
FI−46
EFI SYSTEM
−
FI−47
Troubleshooting with Volt Ohmmeter
There is no voltage between ECU terminals THG and E2.
(IG SW ON)
Check that there is voltage between ECU terminal + B
(+ B 1) and body ground. (IG SW ON)
Refer to No. 1.
(See page FI−34)
Check wiring between ECU terminal E1 and body ground.
BAD
Repair or replace.
BAD
Check EGR system.
Repair or replace.
K
CISCO IDS PAR
TS
CT
JE
O
Check EGR gas temp. sensor.
(See page FI−81 )
BAD
Replace EGR gas
temp. sensor.
Check wiring between ECU and
EGR gas temp. sensor.
BAD
.CISCOKIDS.C
WW
O
M
W
.A
U
Try another ECU.
PR
Repair or replace.