Vehicle Speed Sensor: Description and Operation

The vehicle speed sensor (VSS) is mounted on the transaxle and provides a speed signal to the Generic Electronic Module (GEM). At speeds above 24 kph (15 mph) the door signals (courtesy lamp switches) are ignored for venting operations.

Vehicle Speed Sensor (VSS):

The Vehicle Speed Sensor (VSS) is a variable reluctance sensor that generates a sine wave type waveform with a frequency that is proportional to the speed of the vehicle. If the vehicle is moving at a relatively low velocity, the sensor produces a signal with a low frequency. As the vehicle velocity increases, the sensor generates a signal with a higher frequency. The PCM uses the frequency signal generated by the VSS (and other inputs) to control such parameters as fuel injection, ignition timing, transmission/transaxle shift scheduling and torque converter clutch scheduling.