With Four Wheel Antilock Brakes

CAB/HCU:

The CAB is mounted on the top of the hydraulic control unit.

The CAB operates the ABS system and is separate from other vehicle electrical circuits. CAB voltage source is through the ignition switch in the RUN position.

The CAB contains dual microprocessors. A logic block in each microprocessor receives identical sensor signals. These signals are processed and compared simultaneously.

The CAB contains a self check program that illuminates the ABS warning light when a system fault is detected. Faults are stored in a diagnostic program memory and are accessible with the DRB scan tool.

ABS faults remain in memory until cleared, or until after the vehicle is started approximately 50 times. Stored faults are not erased if the battery is disconnected.

NOTE: If the CAB needs to be replaced, the rear axle type and tire revolutions per mile must be programmed into the new CAB.