Vehicle Speed Sensor (VSS)

VSS generates a pulsed vehicle speed signal to ECU. Speed sensor consists of a reed switch and rotating permanent magnet, which are installed in speedometer unit. Changes in polarity caused by the rotating magnet (located adjacent to reed switch) open and close reed switch, which has a constant polarity of its own.

On Q45, a second speed sensor consisting of a Permanent Magnet (PM) generator and pick-up coil assembly is located in transmission. Rotating PM generator produces an AC voltage signal in winding of pick-up coil. Signal generated by speed sensor is used by transmission control unit and monitored by ECU.