Vehicle Speed Sensor: Description and Operation

Vehicle Speed Sensor (VSS):

PURPOSE
The Vehicle Speed Sensor (VSS) generates a frequency signal input to the Powertrain Control Module (PCM) to control such parameters as fuel injection, ignition timing, transaxle shift scheduling, torque converter clutch scheduling and vehicle speed.

DESCRIPTION
The 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.