Antilock Brakes / Traction Control Systems: Description and Operation
Anti-Lock ControlAnti-Lock Brake System (ABS)
The ABS consists of the following components:
^ Hydraulic control unit (HCU)
^ ABS module
^ Rear wheel speed sensor
^ Rear wheel speed sensor ring
^ Front wheel speed sensors
^ Front wheel speed sensor rings
^ Stoplamp switch
^ Traction control switch (TCS) (PCM controlled)
The ABS prevents wheel lock-up by monitoring the wheel speed sensors and actuating the valves in the HCU which modulates the brake pressure to the brake calipers. By preventing the wheels from locking up, the driver is able to maintain steering control and stop in the shortest possible distance under most conditions. The traction control system is controlled by the PCM and utilizes the ABS module for wheel speed information only. Engine only traction control (EOTC) helps maintain vehicle control during acceleration by modulating engine torque when driving on slippery or loose surfaces.
The front wheel speed sensor rings are integral to the front hub and bearing assemblies.
The rear wheel speed sensor ring is integral to the rear axle.