Tone Wheel

SENSORS
Wheel Speed Sensors and Tone Wheels: One wheel speed sensor (WSS) is located at each wheel. The sensor has internal circuitry powered by 12 volts from the controller antilock brake (CAB). The sensor generates and sends a DC voltage signal back to the CAB. The signal is toggled in proportion to the speed of the toothed tone wheel as it passes the sensor pole. The CAB uses the signal to activate ABS functions as required.

Because of the internal circuitry, correct sensor function cannot be determined by a resistance check across the pins of the sensor.

The front wheel sensors are attached to a boss in the steering knuckle. The tone wheels are an integral part of the front axle shaft. The rear speed sensors are mounted in the caliper adapter plate and the rear tone wheels are an integral part of the rear rotor hubs. The wheel speed sensor air gap is NOT adjustable.

Correct antilock system operation is dependent on wheel speed signals from the wheel speed sensors. The vehicle's wheels and tires should all be the same size and type to generate accurate signals. In addition, the tires should 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; however, the system will continue to function when using the correct factory mini-spare.