Diagnostic Aids
WARNING: This page is about a different car, the 2019 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.
A high resistance in the signal circuit may not set a DTC. Symptoms could include an inoperative manual mode Up/Down, or a Down when the Up button is pressed. DTCs P0815 or P0816 may be driver induced by pressing the plus (+) or minus (-) button for greater than 10 minutes when the Transmission Shift Lever is not in the L position.