Transmission Position Sensor/Switch: Description and Operation

Park/Neutral Switch (Auto. Trans):

The PARK/NEUTRAL (P/N) switch indicates to the computer when the transmission is in PARK or NEUTRAL. This information is used by the computer for ignition timing, Idle Air Control (IAC) operation, EGR and Canister Purge operation. DO NOT drive the vehicle with the PARK/NEUTRAL switch disconnected, since idle quality may be affected.