Transmission Position Sensor/Switch: Description and Operation

PURPOSE
The Powertrain Control Module (PCM) monitors the Transmission Range (TR) sensor inputs to determine the position of the manual shift lever. This information is used in determining desired gear and electronic pressure control pressure. The TR sensor is mounted on the manual lever and also houses other circuits such as the BACK-UP and START circuits.






CONSTRUCTION
The TR sensor is a ratiometric sensor with six discreet resistors in series. The sensor is decoded by looking at differential voltages produced in each of the shift lever positions. (On Escort/Tracer models the TR sensor incorporates a series of switches that are closed depending on shift lever position.)