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 engine (PCME) 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" where it is then passed along to several other control modules as a vehicle speed related input signal.