RS6 Transmission Nightmare: No Start & Shift Lock Failure

Had nearly identical transmission issues with my 2016 RS7. As someone with moderate experience working on cars, I first thought it was just a transmission sensor acting up, but it turned out more serious. The symptoms matched exactly, rough shifting, transmission failure warnings, and that annoying shift lock problem in park. After dealing with similar automatic transmission issues, I can tell this usually points to a control unit problem rather than mechanical failure. Took it to my regular workshop where they diagnosed a defective transmission control unit. The full repair including parts and labor came to 1000 Euro. They had to order the control unit which took 2 days, but the actual repair only needed about 4 hours. The good news is that once fixed, all transmission issues cleared up completely. No more problems with the shift lock or rough shifting since then. Could you share: Current mileage on your RS6? Any transmission service history? Are you getting specific error codes? Any unusual sounds when shifting? This info would help determine if your issue is similar to what I experienced. Transmission repair costs vary significantly based on the exact problem, but control unit issues are generally more straightforward than mechanical transmission failures.

Had my service done at 196000 KM just last week, and I am getting error codes P0706 and P0705. The gear shifter makes a clicking sound when moving between positions. I see similar symptoms to yours, the transmission staying in neutral and shift lock problems. Thanks for sharing your experience, especially the repair costs and timeline details. The park brake also engages out of nowhere when this happens. After reading your post, I am more convinced this could be the transmission control unit rather than a full transmission failure.

Thanks for the additional details. Those error codes (P0705/P0706) definitely point to a transmission range sensor issue, which aligns perfectly with the symptoms I experienced. The clicking sound and unusual park brake engagement are also telltale signs of a failing control unit, just like what happened with my RS7. In my case, the clicking noise got progressively worse before the transmission control unit completely failed. The gear linkage system was also affected, causing that unusual neutral position problem we both experienced. The shift lock malfunction is usually directly connected to the control unit rather than indicating mechanical transmission damage. The fact that you recently had service work done is actually good news, it rules out basic maintenance issues. My automatic transmission problems started around 185000 KM, so the mileage patterns match up too. A transmission repair shop should be able to confirm if its the control unit by testing the sensor signals. If its the same issue I had, you are looking at roughly 1000 Euro plus diagnostic fees. Much better than a full transmission replacement. Just make sure they check the wiring harness connections too, in some cases, the transmission sensor can show similar symptoms due to corroded connections, which would be an even cheaper fix.

Sure, I will complete it from's perspective: Really appreciate the detailed response. Just got back from the shop and you were spot on, they confirmed the transmission control unit is failing. The mechanic mentioned exactly what you described about the wiring harness and ran a full diagnostic. They quoted 1200 Euro for the complete repair including the new control unit and labor. The automatic transmission symptoms match your experience perfectly, particularly the shift lock problems and transmission getting stuck in neutral position. They also found some minor corrosion on the sensor connections which they will clean up during the repair. Thankfully the park brake unusual engagement will also be resolved once they replace the control unit since its all connected to the same system. They estimated 4-5 hours for the full repair once the part arrives. Going ahead with the repair next week. Much relieved its not a complete transmission failure. Thanks again for helping me understand the likely cause and potential costs before visiting the shop. Really helped me have an informed discussion with the mechanic about the transmission issues.