Faulty ABS Sensor Triggers Multiple Warning Lights

I had a similar issue with my A3 diesel from 2002. With some experience working on cars, I can say these ABS and traction control problems can be tricky to diagnose correctly. The electronic stability system and ABS warnings appeared suddenly during normal driving. The workshop performed a diagnostic scan which revealed the control unit was defective, not just the lateral sensor. They explained that moisture had damaged the unit over time. The repair cost me 1000 Euro, including: Complete diagnostic testing, New control unit installation, Steering angle sensor calibration, System programming, Final testing of all safety systems After the fix, all warning lights cleared and the ABS/traction control systems worked perfectly again. The workshop also checked the wheel alignment to ensure everything was properly calibrated. To help better with your specific case, could you share: Any recent changes or repairs before the issue started, Whether the problem occurs more in wet conditions, If you notice any unusual brake behavior, The exact error codes from your diagnostic scan This would help determine if your issue matches what I experienced with my control unit replacement.

Last serviced 2 weeks ago at 157008 KM. After reading your detailed response, I suspect my vehicle stability issues might be more complex than initially thought. The yaw rate sensor was actually tested during my last service when they noticed irregular traction control behavior, but they found it working properly. The safety warning lights started appearing intermittently, especially during cornering maneuvers. The workshop quoted 1200 Euro for a complete control unit replacement, which seems in line with your experience. They mentioned potential water damage near the ABS module, similar to your case. Before proceeding with such an expensive repair, I would like to get a second opinion on whether just replacing the lateral sensor might solve the issue. Has anyone tried cleaning the connections first? The error codes keep returning even after resetting them.

Thanks for providing those details about your service history and symptoms. Your situation does sound remarkably similar to what I experienced, particularly the intermittent warning lights during cornering. While cleaning connections can help in some cases, the persistent error codes and stability issues you describe match the pattern of a failing control unit. In my case, attempting to clean connections only provided temporary relief. The safety warning lights returned within days. My experience with just replacing the lateral sensor first proved costly in the long run. I spent 300 Euro on the sensor replacement, only to need the full control unit replaced two months later. The diagnostic scan eventually confirmed internal corrosion in the control unit itself. The 1200 Euro quote for the control unit replacement actually sounds reasonable considering: The complexity of electronic control unit programming, Required wheel alignment verification, Steering angle sensor calibration, Full system testing The water damage near your ABS module matches what caused my unit to fail. A proper fix requires addressing the moisture intrusion point to prevent future issues. Once replaced, my steering stability and traction control have worked flawlessly for the past 18 months. The error codes returning after reset strongly suggests an underlying hardware issue rather than just sensor problems. This persistent behavior mirrors what I experienced before the full unit replacement.

The workshop clarified things by showing me the actual error logs from the diagnostic scan. Now I better understand why just cleaning connections or replacing the lateral sensor alone might not fix my vehicle stability issues. The persistent nature of these error codes, even after resetting, really does point to a control unit problem. Their assessment of water damage near the ABS module combined with my yaw rate sensor test results makes the 1200 Euro repair quote seem more reasonable. Given that others have spent extra money trying partial fixes first, going straight for the control unit replacement might be more cost-effective. The traction control problems during cornering are becoming more frequent, and I want to ensure all safety systems work properly. Since my vehicle shows such similar symptoms to other cases where cleaning connections only provided temporary relief, I will probably schedule the full repair next week. One final question though, has anyone successfully identified and fixed the source of moisture intrusion when doing this repair? I want to make sure the new control unit stays protected once installed.