Antilock Brakes / Traction Control Systems: Description and Operation

Anti-Lock Control

The anti-lock control system consists of the following components:

- ABS module
- Front wheel speed sensor
- Front wheel speed sensor tone ring (part of the front rotor in Rear Wheel Drive (RWD) vehicles, part of the front wheel bearing assembly in Four-Wheel Drive (4WD) vehicles)
- Hydraulic Control Unit (HCU)
- Rear wheel speed sensor (located in the center top position on the rear axle assembly)
- Rear wheel speed sensor tone ring (part of the rear differential)

The ABS prevents wheel lockup by monitoring the wheel speed sensors and actuating the HCU modulating the brake pressure to prevent wheel lockup. 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.