Transmission Speed Sensor: Description and Operation

VEHICLE SPEED SENSOR (SPEED CONTROL OPERATION)
The Vehicle Speed Sensor (VSS) is mounted to an adapter near the transmission output shaft. The sensor is driven through the adapter by a speedometer pinion gear.

The VSS is a pulse generator. The VSS pulse signal to the speedometer/odometer is monitored by the PCM speed control circuitry to determine vehicle speed and to maintain speed control set speed.