Transmission Mode Switch: Description and Operation
DESCRIPTION AND OPERATIONNOTE: The vehicle should not be driven with the transmission range switch disconnected; idle quality will be affected.
The four inputs from the transmission range switch indicate to the Powertrain Control Module (PCM) which position is selected by the transmission selector lever. This information is used for ignition timing, EVAP canister purge, Exhaust Gas Recirculation (EGR) and Idle Air Control (IAC) valve operation.