Vehicle Speed Sensor: Description and Operation

General Description
The PCM determines the speed of the vehicle by converting a pulsing voltage signal from the vehicle speed sensor (VSS) into miles per hour. The PCM uses this signal to operate the cruise control, speedometer, and the TCC and shift solenoids in the transmission. For more information on the TCC and shift solenoids, refer to 4L30-E Automatic Transmission. With the ignition switch in ON or START the VSS receives power. For every rotation the VSS outputs tour pulses to the cruise control unit, powertrain control module (PCM), and the speedometer to gauge speed.