Vehicle Speed Sensor: Description and Operation

Vehicle Speed Sensor (VSS):

PURPOSE
The Vehicle Speed Sensor (VSS) generates a waveform with a frequency that is proportional to the speed of the vehicle.

OPERATION

How The Signal Is Generated
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.

How The Signal Is Used
The Powertrain Control Module (PCM) uses the frequency signal generated by the VSS to control such parameters as fuel injection, ignition timing, transmission / transaxle shift scheduling and torque converter clutch scheduling.

CONSTRUCTION
The VSS is a variable reluctance or hall effect type sensor.