Service manual

Group 59 Anti-Lock Brake System (Bendix) Design and Function

ABS Fault Detection

During operation, the ABS continuously monitors the

system for faulty conditions. The system components are

checked to ensure they are in working order. If the ABS

detects that a fault has occurred, as determined by the

absence of correct signals from one of the ABS compo-

nents, the system illuminates the ABS warning lamp.

This lamp will stay on until the system has been repaired

and the fault has been cleared from the system memory.

Note: When the system detects a fault, it deactivates

the anti-lock braking function for the wheel that has

the fault. For example, if a fault is detected in the

right front modulator, the ABS function for that

wheel will be disabled. However, normal braking abil-

ity is still available for this wheel. ABS function is

still available for the remaining wheels.

The Bendix ABS ECU has the ability to store the details

of faults that it detects within its own memory so that the

technician can easily locate the problem.

The details of the fault are stored in the system memory

and will remain there until the fault has been repaired

and the technician clears the fault memory. If the fault

was intermittent, the details of the fault are stored only

as long as the fault symptom is present. When the

symptom disappears, the system returns to normal.

Following detection of any fault, the ABS warning light

will go ON and stay on until the ignition is switched to

OFF. If the fault is temporary, the warning light will go out

normally when the vehicle reaches 11 km/h (7 mph). If

the fault still exists, the warning light will remain on until

the fault is repaired and is cleared from the memory.

The ABS can store the details of several faults within its

memory. The ECU LEDs will indicate ONLY ONE fault at

a time, even if there are mutiple faults. The faults must

be repaired and removed from memory one at a time in

the order they are displayed when using the ECU LEDs

to troubleshoot. The instrument cluster may display mul-

tiple codes, but faults can be repaired in any order. The

ABS warning light will not go out while the vehicle is

being driven until all faults have been corrected and re-

moved from memory.

W3000905