Wheel Speed Sensor: Description and Operation

OPERATION

The sensors convert wheel speed into a digital signal. The ABM sends 12 volts to the sensors. The sensor has an internal hall sensor that alters the voltage and amperage of the signal circuit. This voltage and amperage is changed by magnetic induction when the toothed tone wheel passes the wheel speed sensor. This digital signal is sent to the ABM. The ABM measures the voltage and amperage of the digital signal for each wheel.

The signal strength is affected by the distance between the Sensor and the tone ring. If the "Air Gap" between the WSS and the tone ring/wheel is too large, the WSS signal can drop out at low speed, (below 40 mph) and can cause an ABS activation.