Vehicle Speed Sensor: Description and Operation

Vehicle Speed Sensor Operation:

Function
The Vehicle Speed Sensor (VSS) is an electronic relay that is mounted on the transaxle. As the transaxle turns the VSS, the VSS provides the speedometer with a vehicle speed input (voltage pulses).

ECM Input
This input is used to drive the speedometer. The speedometer then converts this vehicle speed input into a more precise waveform and provides the ECM with its own speed input. The ECM converts this this input into a vehicle speed.

Failure Code
A failure in the TPS sensor circuit should set a Diagnostic Trouble Code (DTC) 42.