Transmission Position Sensor/Switch: Description and Operation

PURPOSE
The signals from the A/T Gear Position Switch are monitored by the Engine Control Module (ECM) which uses the information to control power to Lock-up Control Solenoids 1 and 2, and adjust in-gear idle speeds.

OPERATION
A 5.0 volt signal is output from the ECM at terminal B7. With the transmission in [P] or [N] position and the engine running, the signals ground path is interrupted by the Gear Position Switch. When the transmission is placed into any other gear range, the 5.0 volt signal passes through the contacts in the Gear Position Switch and returns to ground through ECM terminal A26.

Similarly, the signal for gear positions [D3] and [D4] are out put from ECM terminals B3 and B4, respectively. When the gear selector is in those positions the ECM signal passes through the Gear Position Switch and returns to ground at ECM terminal A26.