Audi A7: ABS Light & Traction Control Failure Fix

As someone with moderate experience working on Audis, I faced a similar issue with my 2015 Audi A6 3.0 TFSI. The symptoms matched exactly, ABS light, traction control deactivation, and speed sensor readings showing errors during diagnostic scans. After taking it to a specialist workshop, they found the ECM (Engine Control Module) was misreading input signals from the wheel speed sensors. The transmission itself was functioning correctly, but the main control unit responsible for processing the sensor data had failed. The total repair cost was 1000 Euro, which included: Complete diagnostic testing, Control unit replacement, System recalibration, Final testing To properly diagnose your specific case, could you provide: Exact error codes from the diagnostic scan, Whether the issue happens consistently or intermittently, If any other warning lights appeared before or after, Information about recent repairs or maintenance This could help determine if your A7 is experiencing the same control unit failure or if its related to a different sensor issue.

Thanks for the insight. My vehicle has 133208 KM on the odometer and the last service was done at 130000 KM. After reading your reply, I checked the dashboard more carefully. Noticed the speedometer occasionally flickers when the ABS warning appears. The malfunction happens consistently after the car warms up, usually within 15 minutes of driving. Will get the exact error codes from another scan tomorrow. No other warning lights have appeared yet. The input from wheel sensors seems inconsistent according to the first diagnostic readout. Hoping its just a sensor issue rather than a complete control unit failure.

Thanks for the additional details. The flickering speedometer combined with timing-based symptoms brings back memories of my A6 repair experience. In my case, those exact symptoms, intermittent speedometer readings and warm-up related issues, pointed to a faulty wheel speed sensor rather than the complete ECM failure I initially suspected. The repair ended up being much simpler and cheaper than the control unit replacement: Single wheel speed sensor replacement: 180 Euro, Labor costs: 120 Euro, System recalibration: 100 Euro Total: 400 Euro The dashboard warning pattern you described strongly suggests a sensor malfunction rather than a complete ABS system failure. The timing correlation with engine warm-up often indicates wiring issues or a degraded sensor that becomes problematic at certain temperatures. Before replacing the entire control unit, request the workshop to: Check all wheel sensor wiring connections, Test sensor resistance values at different temperatures, Verify the signal output from each wheel sensor Getting those additional error codes will help confirm, but based on these symptoms, you might be looking at a simpler fix than my initial suggestion.

Thanks everyone for the detailed responses. Got the second diagnostic scan done and error code points to the right rear wheel speed sensor (P0501). The transmission and other systems seem fine. The speedometer fluctuation matches exactly what was described, occurs after warm-up and the readings become erratic. The repair estimate from my local workshop aligns with the 400 Euro range mentioned. Good to know its likely just a sensor replacement rather than a full control unit issue. Will have them check all the wiring connections during the repair as suggested. Really helpful to understand the common symptoms and potential causes before going in. Will update once the repair is completed in case anyone else runs into similar ABS and traction control warnings on these models.