Circuit/System Description

The vehicle speed sensor (VSS) is a 3 wire sensor. The engine control module (ECM) provides a 5 volt reference circuit, low reference circuit and a signal circuit to the VSS. The VSS is a Hall Effect type sensor that produces a square wave output signal to the ECM. As vehicle speed increases, the output frequency of the VSS signal increases. The ECM converts the square wave output signal into vehicle speed shown as km/h (MPH). The ECM supplies the VSS signal to other control modules on the vehicle through the serial data communications circuit.