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ABS System Overview and Components
Electronic Control
Unit (ECU)
The Electronic Control Unit (ECU) handles the processing
function of the ABS. It receives and interprets the wheel speed
signals from the sensors and uses this information to determine if
a wheel is going to lock and when and how to activate the ABS
valves. Through this valve actuation, the ECU can regulate air
pressure to the brake chambers. Cab and chassis harnesses
connect the ECU to the following ABS components:
r Wheel speed sensors
r ABS modulator valves
r Power source
r Ground
r ABS indicator lamp
r Blink code switch
r J-1587 Diagnostic Connector
r Retarder control (via relay or J1922/J1939 datalink)
ECU Types
Three types of electronic control units are available with WABCO
ABS.
r D-Basic version cab-mounted ECU
r D version cab-mounted ECU
r D version frame-mounted ECU
The type of ECU used and its mounting location varies by
manufacturer and application. For more detailed information,
consult the vehicle manufacturer’s service literature.
The D-Basic version ECU is smaller than the other two versions,
and has only two connector ports. The D-Basic ECU is used
exclusively with vehicles that only have ABS and do not have
optional ATC. The D-Basic ECU is mounted within the vehicle
cab.
D-Basic Version Electronic Control Unit
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