Antilock Brakes / Traction Control Systems: Description and Operation

Anti-Lock Control


ABS With Traction Control and Electronic Stability Control (ESC)

The ABS with traction control and electronic stability control consists of the following components:

- ABS module
- Front wheel speed sensors
- Front wheel speed sensor rings (integral to the front wheel bearing)
- Hydraulic Control Unit (HCU)
- Rear wheel speed sensors
- Rear wheel speed sensor rings (integral to the rear wheel bearing)
- Stability control sensor cluster
- Steering wheel rotation sensor
- Stability/traction control switch

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 utilizes the same components as the ABS to prevent wheel spin and help maintain vehicle control during acceleration. The electronic stability control system utilizes the same components as the ABS and the traction control systems. The electronic stability control system also monitors the steering wheel position sensor and the stability control sensor cluster to assist in stabilizing the vehicle during abrupt maneuvers.

The front wheel speed sensor rings are integral to the front hub and bearing assemblies.

The rear wheel speed sensor rings are integral to the rear hub and bearing assemblies.