Operation CHARM: Car repair manuals for everyone.

Purpose

The Vehicle Speed Sensor provides information to the ECM/PCM for control of idle speed and transmission converter clutch engagement, shift solenoid control, and canister purge of the fuel evaporative emission system. This signal is generated by an inductive sensor located in the transmission. The sensor produces an alternating or "ON/OFF" signal. As the vehicle speed increases, so does the frequency of the signal pulses.