Electronic Brake Control Module: Description and Operation

DESCRIPTION
The ABS control module:
^ Is located below the brake pressure control valve block.
^ Is an on-board diagnostic non-repairable unit consisting of two microprocessors and the necessary circuitry for their operation. The ABS control module monitors system operation during normal driving as well as during anti-lock braking and traction control cycling.

OPERATION
ABS Module Operation - is as follows:
^ Under normal driving conditions, the microprocessors produce short test pulses to the solenoid valves that check the electrical system without any mechanical reaction.
^ Impending wheel lock conditions trigger signals from the ABS control module that open and close the appropriate solenoid valves.
^ When the pump motor starts to run, the driver may hear some noise and will feel moderate pulsations in the brake pedal.
^ During normal braking, the brake pedal feel will be identical to a standard brake system.

During Traction Control Operation - the ABS control module operates as follows:
^ During acceleration, if one or both rear wheels lose traction or begin to spin, the ABS control module will close the isolation valves and operate the pump motor. If the driver applies the brakes during cycling, the system will automatically shut off.
^ The ABS control module monitors traction control usage and will shut off the traction control features to prevent overheating of the rear brakes.
^ If the system shuts off, there is a cool-down period required before it becomes functional again. This period varies depending on brake usage during the cool-down period.
^ Anti-lock braking is still fully functional during the cool-down period.
^ Most concerns in the ABS system and the traction control will be stored as a Diagnostic Trouble Code (DTC) in the keep-alive memory of the ABS control module. DTCs can be retrieved by following the on-board diagnostic procedures. Refer to Diagnosis and Testing.