Transmission Position Sensor/Switch: Description and Operation

OPERATION
- The ignition switch-ST inputs a high signal to the engine control module while the engine is cranking. The engine control module provides fuel injection control, etc., at engine start-up based on this signal.
- When the ignition switch is set to START, the battery voltage at cranking is applied through the ignition switch and park-neutral position switch to the engine control module, which detects that the engine is cranking.
In case the selector lever is in a position other than the P/N range, the battery voltage is not applied to the engine control module.
- The park/neutral position switch converts the selector lever position (whether it is at the P/N range or at others) into high/low voltage and inputs it to the engine control module, which then controls the idle air control motor based on this signal.
- The battery voltage in the engine control module is applied through a resistor to the park/neutral position switch. When the selector lever is set to the P/N range, continuity is produced between the park/neutral position switch terminal of the engine control module and ground through the starter motor, thereby making the terminal voltage go low.

TROUBLESHOOTING HINTS
If the park/neutral position switch harness and individual part checked good but the park/neutral position switch output is abnormal, poorly adjusted control cable is suspected.