Wheel Speed Sensor
An electronic sensor mounted near the wheel hub that monitors the rotation of each wheel to provide data to the ABS and traction control systems.
Wheel speed sensors (also called ABS sensors) are magnetic transducers positioned adjacent to a rotating toothed ring (tone ring) on the axle shaft or wheel hub. As the wheel spins, the tone ring teeth disrupt the sensor's magnetic field, generating an AC voltage signal proportional to the wheel's rotational speed.
This data is transmitted to the ABS control module, traction control system, and electronic stability control (ESC) systems. Because they are located near the wheels, these sensors are constantly exposed to water, road grime, salt, and brake dust, which can cause electrical shorts or physical damage.
A failed sensor will disable the ABS and illuminate dashboard warning lights. Replacing the sensor is a common repair that restores standard vehicle safety systems.