TR Sensor
WARNING: This page is about a different car, the 2016 Lincoln MKS. However, it is still accessible from the selected car via links, so may be relevant.
The TR sensor is located inside the transaxle and indicates gearshift position to the PCM. The PCM uses that information to enable the starting system to start the engine in PARK or NEUTRAL. For additional information, refer to Automatic Transmission - 6F50/6F55 .