Wheel Speed Sensor: Description and Operation

VARIABLE-RELUCTANCE SENSORS
The ABS system uses four variable-reluctance ABS sensors to determine the rotational speed of each wheel. The front brake anti-lock sensors and rear brake anti-lock sensors operate on magnetic induction principle. As the teeth on the brake anti-lock sensor indicators rotate past the stationary brake anti-lock sensors, a signal proportional to the speed of the rotation is generated and sent to the ABS control module through a twisted pair harness.

Front
The front brake anti-lock sensors are attached to the front wheel spindles. The front brake anti-lock sensor indicators are pressed onto the wheel hub assemblies.

Rear
The rear brake anti-lock sensors are attached to the rear wheel disc brake adapters. The rear brake anti-lock sensor indicators are pressed onto the axle shafts.