Wheel Speed Sensors

Fig. 7 - Front Wheel Speed Sensor:

Fig. 8 - Rear Wheel Speed Sensor:

One wheel speed sensor (WSS), is located at each wheel (Fig. 7), and sends a small (AC) signal to the control module (CAB). This signal is generated by magnetic induction when a toothed sensor ring tone wheel passes a stationary magnetic sensor wheel speed sensor. The (CAB) converts the (AC) signal generated at each wheel into a digital signal. If a wheel locking tendency is detected, the (CAB) will then modulate hydraulic pressure to prevent the wheel(s) from locking.

The front wheel speed sensor is attached to a boss in the steering knuckle. The tone wheel is part of the outboard constant velocity joint. The rear wheel speed sensor is mounted to the caliper adaptor and the rear tone wheel is an integral part of the rear wheel hub. The speed sensor air gap is NOT adjustable.

The four wheel speed sensors are serviced individually. The front tone wheels are serviced as an assembly with the outboard constant velocity joint. The rear tone wheels are serviced as an assembly with the brake hub.

Correct anti-lock system operation is dependent on wheel speed signals from the wheel speed sensors. The vehicles' wheels and tires must all be the same size and type to generate accurate signals. In addition, the tires must be inflated to the recommended pressures for optimum system operation. Variations in wheel and tire size or significant variations in inflation pressure can produce inaccurate wheel speed signals.