Vehicle Speed Sensor: Description and Operation

The Vehicle Speed Sensor generates a signal that is proportional to vehicle speed. The signal produced is a sine wave, which the PCM processes into a square wave to supply inputs to the Speedometer, the Head Up Display Control Module (if equipped), the Multi-Function Chime (MFC) Module and the Computer Command Ride (CCR) Controller (if equipped).

The PCM takes the sensor/voltage pulses from the Vehicle Speed Sensor, through the PPL and YEL wires, and uses them to close solid-state output switches. The output terminals are switched to ground at a rate that is proportional to vehicle speed.