I have a 2014 Cadillac XTS luxury series, and I recently bought a transmission from LKQ with 60K miles which belong to a 2013 Cadillac XTS. Right after I pick up the car my check engine came up, I check it with OBDII, and it was U0101, but the car is running perfect, not stucking in any gear. I test it in highway, no rattling, not shaking, shifting very smooth, I clean the code, but it came up again, here's the question: is there a procedure for reprogramming the TCM and is it necessary? Or you think it's the transmission? Do I need to return it? Or it's a simple problem? Any help would be appreciated.