Wheel Speed Sensor: Description and Operation

WHEEL SPEED SENSORS





Front wheel speed sensor





Rear wheel speed sensor

The speed sensors are a single pole, variable reluctance sensor, mounted to both rear hubs and both front half shafts. A toothed tone ring is press fit to the rear hub assemblies and provides the signal for the rear sensor. The front tone rings are press fit to the half shaft assemblies. The signal generated is proportional to the speed of the wheels and is used by the ECU to monitor the wheel speeds.





As the teeth of the tone ring move through the magnetic field of the sensor, an AC voltage is generated. This signal frequency increases or decreases proportionally to the speed of the wheel. The ECU monitors this signal to check for changes in wheel speeds. If the deceleration of one or more wheels is not within a predetermined amount, an ABS event is initiated.