GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hi and thanks for your question. The seat not moving backward could be several things. This could be a seat issue, wiring issue going from the switch to the power seat motor, or a seat motor internal malfunction. The most common item that causes this issue is the switch. I would have it diagnosed at your local trusted garage or local GM dealer. As for the Service Engine Soon (SES) light that is on, if it's a transmission code, it'll have to be diagnosed and inspected by a certified driveline specialist. This light can come on for many many internal transmission issues. Unfortunately, there is no way to diagnose a transmission issue via the internet by having only a trans code - If you figure out a way to do that, let me know - we'll be rich!! Thank you so much for the inquiry and let me know if I can be of further assistance.