Faulty ABS Sensor Disrupts Audi S6 Traction Control

Had a very similar issue with my 2021 Audi S4 last winter. With some experience working on cars, I initially thought it was just a sensor problem, but the diagnostic tests revealed more complex issues. The speedometer was working normally like in your case, but the ABS control unit itself was malfunctioning. The workshop ran thorough input tests and found the ABS control unit was defective, requiring complete replacement. The total repair cost was 1000 Euro, including parts and labor. The symptoms you describe match exactly what I experienced, ABS warning light and compromised traction control, despite working odometer readings. The transmission and other components were fine in my case; it was isolated to the control unit. Before suggesting specific solutions, it would help to know: Have you noticed any other warning lights? Does the traction control light flash during normal driving? Did the issue start suddenly or develop gradually? Have you had any recent work done on the braking system? This information would help determine if your issue is similar to what I encountered or if it might be something different.

Thanks for the detailed response on my Audi S6 ABS issue. After the last service at 191299KM, I did notice the traction control light started flashing intermittently during normal driving. The ABS warning on the dashboard appeared quite suddenly, not gradually. No other warning lights are present and I have not had any recent brake work done. The transmission behaves normally otherwise. Your experience with the control unit replacement is helpful, I will have a diagnostic scan done to check if my issue has the same root cause. The 1000 Euro repair cost gives me a good reference point for budgeting. I appreciate the thorough technical input.

Based on those additional details about your S6, I am even more convinced your issue mirrors what I experienced with my S4. The intermittent traction control light flashing after service, combined with the sudden ABS warning, strongly suggests an ECM/ABS control unit malfunction rather than a simple sensor fault. In my case, the intermittent flashing was the key indicator that helped pinpoint the control unit as the culprit. The timing after service is interesting, sometimes disconnecting and reconnecting components during routine maintenance can expose existing weaknesses in control modules. The diagnostic scan should confirm, but the matching symptoms and normal transmission behavior point to a control unit replacement being necessary. The repair costs remain fairly consistent, my 1000 Euro fix included the new unit, programming, and testing to ensure proper integration with other systems. Given these similarities, I would advise moving forward with the diagnostic test to verify the control unit malfunction before exploring other potential causes. This should help avoid unnecessary parts replacement and keep repair costs in line with what I experienced.

Since you are correct about the likely cause matching my S6 symptoms, I will schedule the diagnostic scan this week. The behavior matches exactly what you experienced, traction control light flashing after service and sudden ABS dashboard warning, with everything else functioning normally. The ECM/ABS control unit theory makes sense, especially since the speedometer and transmission are working fine. Having a realistic cost estimate of around 1000 Euro for the complete repair helps with planning. The timing connection to recent service is particularly interesting since my issues also started after maintenance. I feel more confident now about getting this resolved without extensive transmission work or unnecessary sensor replacements. Will proceed with the diagnostic test to confirm the ABS control unit needs replacement. Thanks for sharing your experience and helping me understand the likely root cause.