Antilock Brakes

Special Tools:

The ABS control module receives wheel speed readings from each wheel speed sensor and processes this information to determine if an ABS event is necessary. The wheel speed sensor electrically senses each tooth of the ABS sensor indicators as it passes through the wheel speed sensors magnetic field.

The ABS control module continuously monitors and compares the rotational speed of each wheel. When the module detects an impending wheel lock, it modulates brake pressure to the appropriate brake caliper. This is accomplished by triggering the Hydraulic Control Unit (HCU) to open and close the appropriate solenoid valves. Once the effected-wheel returns to normal speed, the ABS control module returns the solenoid valves to their normal position and normal (base) braking resumes.

The ABS control module is self-monitoring. When the ignition switch is turned to the RUN position, the ABS control module will do a preliminary electrical check. At approximately 20 km/h (12 mph) the pump motor is turned on for approximately a/2second. Also, during all phases of operation the ABS control module (after the vehicle is in motion) checks for correct operation of the wheel speed sensors. Any malfunction of the ABS system will cause the ABS to shut off however, normal power assisted braking is maintained.

The ABS control module has the ability to store three DTCs in memory.