S7 Transmission Nightmare: TCU Failure Warning Signs

Had very similar transmission control issues with my 2016 S6 last year. Have some experience working on cars but this was definitely above my skill level due to the electronic issues. The symptoms matched yours exactly, gear slipping, grinding, and the paddle shifters stopped responding completely. The transmission would out of nowhere go into limp mode, making the car barely drivable. The automotive ECU was throwing multiple error codes related to the transmission control module. Took it to a specialist workshop that focuses on gearbox issues. Their transmission diagnosis confirmed a defective control unit was the root cause. The entire repair including parts and labor came to 1000 Euro. They had to order a new TCU and program it to match the car. Total repair time was about 3 days. The car has been running perfectly since the fix, no more transmission problems at all. Would definitely recommend getting it checked soon before it potentially causes more damage. Could you share which specific error codes your car is showing? Also, how many miles/kilometers are on the transmission? This info would help confirm if your issue is similar to what I experienced.

Thanks for the detailed feedback on the S6 transmission issues. My automatic gearbox started acting up at 25642 KM during normal driving, shortly after the last scheduled service. The automotive ECU is showing error codes P0730 and P0732 consistently. Based on your experience with the transmission control unit replacement, that repair cost seems reasonable compared to a full gearbox rebuild. The 3-day turnaround time is also helpful to know for planning purposes. Were there any warning signs before your transmission diagnosis revealed the faulty TCU? My gearbox issues seemed to develop quite suddenly without any prior indicators.

Thanks for the follow-up about your S6 transmission issues. When my transmission control problems started, there were actually some subtle warning signs I initially overlooked. About 2 weeks before the complete failure, I noticed slightly delayed responses from the paddle shifters, especially during cold starts. The transmission would also occasionally hesitate between gears, but it was so minor I dismissed it. The error codes you mentioned (P0730 and P0732) are exactly what my automotive ECU was showing. These codes typically point to electronic issues within the transmission control module rather than mechanical gearbox problems. At first, I tried clearing the codes, but they kept returning within a few driving cycles. The specialist explained that when the control module starts failing, it often creates a cascade of electrical issues that get progressively worse. The repair price I quoted earlier included programming and testing, but prices for transmission diagnosis and parts can vary. The most important thing is getting a proper diagnosis quickly, waiting too long with these symptoms risks additional damage to other transmission components. For what its worth, since the control unit replacement, my S6 has shifted perfectly for over 15000 KM now. The original transmission control module failure seems to have been an isolated electronic issue rather than a sign of wider transmission problems.

Thanks for sharing those details about your transmission diagnosis experience. The error codes match my situation perfectly, encouraging to hear it was resolved with a TCU replacement rather than major gearbox repairs. Unfortunately I had zero warning signs before the transmission control issues appeared. Was driving normally when the gearbox suddenly started acting up and the automotive ECU lit up with those error codes. Based on your experience and the matching symptoms, I will focus on getting the electronic issues checked first. Will schedule an appointment with a transmission specialist this week. The 3-day repair timeline works well with my schedule, and 1000 Euro for the fix is much better than I feared. Really helpful to know your S6 has been shifting properly for 15000 KM since the repair, gives me confidence this could be a straightforward fix rather than a catastrophic gearbox failure. Thanks again for the detailed information about your experience with similar gearbox issues. This will help ensure I get the right transmission diagnosis and repair solution.