Transmission Range (TR) Sensor
The TR sensor is a linear potentiometer device that provides the PCM with an input voltage proportional to the gear selected. The PCM determines a gear mode based on the TR input. The PCM then broadcasts a gear mode message over the controller area network (CAN). The PCM uses the gear mode message to engage the transmission in the gear the driver selected. The other control modules use the gear mode message to control the rear lamps or a brake shift interlock solenoid. The TR sensor is located inside the transmission assembly.
If the PCM detects a concern in one of TR signal inputs, it uses the other TR signal to determine what gear the driver selects. If the PCM detects one or more TR signals that are invalid, the PCM:
- allows the vehicle to travel in the DRIVE or LOW gear position if the vehicle was driving forward at a significant speed when the concern was detected.
- allows the vehicle to travel in REVERSE gear if the vehicle was driving backwards at a significant speed when the concern was detected.
- broadcasts gear mode - NEUTRAL over the communication link when vehicle speed decreases to 8 km/h (5 mph).
- sets the DTC and illuminates the malfunction indicator lamp (MIL).