Anti-Lock Control with AdvanceTrac® and Roll Stability Control (RSC®): Notes

The ABS with AdvanceTrac® and Roll Stability Control (RSC®) system consists of the following components:

• ABS module - attached to the Hydraulic Control Unit (HCU), but can be serviced separately from the HCU.
• Front wheel speed sensors - one sensor is located in each front wheel knuckle. The sensors are serviced separately from the knuckle.
• Front wheel speed sensor tone rings - the tone ring is part of the front wheel bearing and is serviced with the bearing on Four-Wheel Drive (4WD) vehicles. On Rear Wheel Drive (RWD) vehicles, the tone ring is part of the front brake rotor and is serviced with the brake rotor.
• HCU - which contains several valves (inlet, outlet, isolation and dump) and the hydraulic pump motor. The HCU is mounted on the LH side of the engine compartment.
• Rear wheel speed sensors - one sensor is located at each end of the rear axle housing. It is mounted to the brake backing plate and can be serviced separately.
• Rear wheel speed sensor tone rings - one tone ring is located on each rear axle shaft and is available for service separate from the axle.
• Stability control sensors - located inside of the Restraints Control Module (RCM) and consist of the following sensors: yaw rate, roll rate, lateral accelerometer and longitudinal accelerometer. The sensors are integral to the RCM and cannot be serviced separately.
• Steering wheel rotation sensor - located at the end of the steering column on the LH side of the column, the slotted wheel is serviced with the steering column but the sensor can be serviced separately.
• Stability/traction control switch - located in the Instrument Cluster (IC) center finish panel and is serviced separately from the finish panel.

ABS aids in the prevention of wheel lock-up during braking events which will allow the driver to maintain steering control and stop in the shortest distance possible under most conditions. This is accomplished by the ABS module and HCU modulating brake fluid pressure to the affected brake caliper(s) and wheel cylinder(s).

When the ABS activates, the driver may notice the following operational symptoms:

• A rumble or grinding sound may be heard (HCU pump motor)
• If the driver's foot is on the brake pedal, a vibration may be felt in the brake pedal (HCU pump motor and valves)