Transmission Position Sensor/Switch: Description and Operation

PURPOSE
The Transmission Range (TR) switch serves a dual purpose:

- The TR switch prevents unintentional vehicle movement caused by engine cranking and starting with the shift control selector lever in a forward or reverse position.

- The TR also informs the Powertrain Control Module (PCM) that transmission is either in neutral or any other gear. Input is used in PCM calculations for fuel injection quantity, idle speed, A/C cut-off, and purge control.

OPERATION
The TR switch is manually controlled by the shift control lever and transmission shift cable. When the transmission is in PARK or NEUTRAL, switch is ON (shows continuity).