The ABS module is self monitoring.
The module will carry out a preliminary electrical inspection of the hydraulic
pump motor by turning the pump ON for approximately 1/2 second either when
the ignition switch is turned to the RUN position and the brake pedal is
not pressed or when the vehicle is in motion and at vehicle speeds above
12 mph. The ABS module will also carry out a wheel speed sensor self-test
by sending a reference voltage to all of the wheel speed sensors through
their circuitry when the ignition switch is turned to the RUN position,
with or without brake pedal application. If a fault is detected in the pump
or wheel speed sensors, the ABS module will shut down and disable the anti-lock
system. Normal power assisted braking, however, remains. |