Vehicle Speed Sensor (VSS)

VSS is mounted on transmission extension housing. VSS produces an AC signal with a frequency proportional to speed at which transmission output shaft rotates, which is also proportional to vehicle speed. The AC signal is sent to cruise control module and speedometer by Powertrain Control Module (PCM). The signal is sent at a rate of 4000 pulses per mile, and the PCM converts number of pulses per mile per to pulses per second to determine speed of vehicle.