Vehicle Speed Sensor: Description and Operation

PURPOSE
The Vehicle Speedometer Sensor (VSS) provides a vehicle speed signal which is used to operate the speedometer and provide an input signal for the Powertrain Control Module (PCM) and other various control modules.

OPERATION
The VSS is an alternating current generator. Voltage output varies with vehicle speed. The VSS signal originates at the transaxle mounted sensor which transmits to the instrument cluster. The signal is processed within the speedometer's "speed circuit". The speedometer "speed circuit" contains a vehicle speed sensor which forwards the VSS signal to several other control modules as a speed related signal.