DTC P0500: VSS Circuit: Description
WARNING: This page is about a different car, the 2002 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The Vehicle Speed Sensor (VSS) is connected to the PCM. The VSS is mounted on the transmission and monitors the axle drive speed. Based upon the signal that is received from the VSS the PCM supplies a vehicle speed output signal on the VSS output circuit. The cruise control module and the alternative fuels engine control module (ECM) utilize the VSS output circuit.
This DTC is used to indicate no VSS output signal is being monitored by the AF ECM while engine sensor conditions indicate the vehicle is moving.