Drive Range, First Gear: Notes
WARNING: This page is about a different car, the 2018 Cadillac XTS. However, it is still accessible from the selected car via links, so may be relevant.
As the vehicle speed increases, the transmission control module (TCM) receives input signals from the automatic transmission input and output speed sensors, throttle position sensor and other vehicle sensors to determine the precise moment to de-energize or "turn off" shift solenoid 1 and command OFF the normally-high R1/456 pressure control solenoid 3.