Circuit 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, Magna Steer Module and the Multi-Function Chime Module.

The PCM takes the voltage pulses from the vehicle speed sensor, through the PPL and YEL wires, and uses them to dose a solid-state output switch. The output terminal is switched to ground at a rate that is proportional to vehicle speed.