A toothed rotor is fixed to the rotating member of the wheel, the sensor to the static member of the suspension. As the wheel rotates the toothed rotor causes magnetic flux changes in the magnetic field of the permanent magnet. The sensor element senses these changes. Depending on the flux changes the sensor sends a signal out to the ECU. The change in magnet flux thus the sensor signal is directly correlated to the wheel speed.

The controller monitors the sensor signal, compares the four wheel-speed signals and initiates action as required.