RSQ3 ABS & Traction Control Issues, Fix Needed

Having experienced a similar issue with my 2021 RS3 with gasoline engine, I understand your safety concerns about the ABS warning light. The symptoms match what I encountered, where both the ABS and traction control systems were compromised. After running a diagnostic scan at my workshop, they identified that the ECM was receiving faulty signals from a defective control unit, which affected both the ABS and traction control systems. The speedometer readings remained accurate because it operates on a separate circuit. The complete repair involved: Full system diagnostic testing, Control unit replacement, System recalibration, ABS sensor verification Total cost came to 1000 Euro, including parts and labor. The repair took about 6 hours to complete. To provide more specific guidance for your case, could you share: Current mileage on your odometer, Whether any recent repairs were done, If the dashboard shows any other warning lights, When the issue first appeared, If the problem is constant or intermittent This information would help determine if your RSQ3 is facing the same underlying issue as my RS3 did.

Thanks for sharing your experience. My current mileage is 180811 KM. The ABS malfunction started about 2 weeks ago, and the warning light remains constantly on. No other repairs were done recently, with my last service being the routine maintenance 3 months ago. The check engine light occasionally flickers but does not stay on. A sensor issue seems likely based on your description, though I hope the ECM itself is not affected as that would increase repair costs significantly.

Glad I could help with the initial information. Based on your mileage and the symptoms described, this increasingly sounds similar to what I experienced with my RS3. The flickering check engine light alongside the constant ABS warning actually reinforces my suspicion about the control unit issue. In my case, the transmission control module was also sending intermittent error signals to the ECM, causing that occasional check engine light flicker. The good news was that the ECM itself was fine, the problem centered on the failing control unit and a worn ABS sensor. Quick tip from my experience: request the workshop to perform a complete diagnostic scan of both the ABS and transmission systems. When they fixed mine, they found that the sensor wiring had deteriorated due to normal wear, which was creating signal interference. The repair cost might be lower than what I paid since you likely only need the sensor replacement rather than the full control unit work I required. From the timeline you shared, addressing this sooner rather than later would be wise to prevent any potential cascade of electrical issues. Would you mind updating this thread after your workshop visit? It would be helpful to know if the root cause matches what I experienced with my RS3.

Thanks for the detailed follow up. After reading about your experience, I made an appointment with my regular workshop for next week. The input from your case is really valuable, I will definitely ask them to check both the ABS sensor and the control unit given the similar symptoms. Your point about the wiring deterioration makes sense given my car's high odometer reading of 180811 KM. I am somewhat relieved that your ECM turned out to be fine despite similar dashboard warning patterns. The speedometer still working correctly while other systems malfunction does align with your explanation about separate circuits. I will make sure to get a complete diagnostic scan as suggested. The intermittent nature of my check engine light compared to the constant ABS warning certainly points toward some kind of sensor communication issue. I will update this thread once I get the results from the workshop. Hopefully it will just be a sensor replacement rather than more extensive control unit work. Thanks again for sharing your repair experience, it helps narrow down the likely causes.