Wheel Speed Sensor: Description and Operation

Each wheel is monitored by a wheel speed sensor, to detect the speed of movement of a toothed gear that is driven by the wheel. Signal's generated by the toothed gear passing the sensor are sent to the ABS/TCCM to communicate the speed of wheel rotation and any rapid change of wheel speed.

The frequency of the sinusoidal output voltage signal from the sensor, is proportional to road wheel rotational speed and the number of teeth on the toothed gear. The amplitude of the voltage is dependent upon the 'air gap' between the sensor and toothed wheel, therefore it is important that this preset gap remains clear and undisturbed.