Wheel Speed Sensor: Description and Operation

FRONT WHEEL SPEED SENSORS
The front wheel speed sensors are of a variable reluctance type. Each sensor is attached to the steering knuckle close to a toothed ring. The result, as teeth pass by the sensor, is an AC voltage with a frequency proportional to the speed of the wheel. The magnitude of the voltage and frequency increase with increasing speed. The sensor is not repairable, nor is the air gap adjustable.


FRONT WHEEL SPEED SENSOR RINGS
The toothed ring is pressed onto the wheel-side (outer) constant velocity joint. Each ring contains 47 equally-spaced teeth. Exercise care during service procedures to avoid prying or contacting this ring. Excessive contact may cause damage to one or of the more teeth. If the ring is damaged, the wheel-side constant velocity joint must be replaced.

REAR WHEEL SPEED SENSORS AND RINGS
The rear wheel speed sensors operate in the same manner as the front wheel speed sensors. They incorporate a length of flexible harness with a connector attached to the end of the harness.