Electronic Brake Control Module: Description and Operation

Anti-Lock Brake Control Module:

The anti-lock brake control module is an on-board diagnostic, non-repairable unit consisting of one microprocessor and the necessary circuitry for its operation. The anti-lock brake control module has two primary functions. It is responsible for the control of the hydraulic control unit during ABS operation and system monitoring during normal driving as well as during anti-lock braking.

^ Under normal braking conditions, the microprocessor produces short test pulses to check the electrical system without any mechanical reaction. The anti-lock brake control module continuously monitors the speed of each wheel to determine if any wheel is beginning to lock. When a wheel-locking tendency is detected, the anti-lock brake control module signals the appropriate isolation valve in the hydraulic control unit to open or close, turn the pump motor on, and return brake fluid back to the foundation braking system. This results in slight pulsations in the brake pedal and pump noise which may be heard in the passenger compartment. During normal braking, the brake pedal feel will be identical to a standard brake system.

^ Most faults which occur in the anti-lock brake system will be stored as a coded number in the Non-volatile Random Access Memory (NVRAM) of the anti-lock brake control module. This means that once a code is stored, it will be retained by the anti-lock brake control module even with the key in the OFF position. The codes can be retrieved by performing the On-Board Diagnostics.