Wheel Speed Sensor: Description and Operation

Fig. 1 Wheel sensor assembly:

This system, Fig. 1, uses four sets of variable reluctance sensors and toothed speed indicator rings to determine the rotational speed of each wheel. The sensors operate on magnetic induction principle. For example, as the teeth on the speed indicator ring rotate past the stationary sensor, a signal proportional to the speed of the rotation is generated and transmitted to the electronic control unit (ECU) through a coaxial cable.


The front sensors are attached to the suspension knuckles and the speed indicator rings are pressed onto the hubs. The rear sensors are attached to rear caliper adapter plates, and the rear speed indicator rings are pressed onto the rear hub assemblies.