Wheel Speed Sensor: Description and Operation

The front wheel speed sensor is installed to the front suspension knuckle and the rear wheel speed sensor to the rear differential carrier.
The front wheel sensor ring is press-fitted into the wheel hub and the rear wheel sensor ring into the differential case.
When the magnetic flux generated from the magnet included in the sensor varies as the sensor ring turns, an AC voltage of proportionate frequency to the wheel speed occurs in the coil also included in the sensor due to the function of electromagnetic induction. The magnitude of the voltage and frequency increase with increasing speed.
As both sensors on the front and rear wheels are unrepairable, they must be replaced when they are found in faulty condition. If the sensor ring is found faulty, replace it.