Audi Q7 ABS Failure Causing Dangerous Traction Loss

Had the same issue with my 2010 Audi A6 3.0 TFSI. The ABS malfunction started similarly with dashboard warnings and traction problems during braking. The ECM was receiving incorrect wheel speed data. The root cause was a failed ABS control unit, not just a sensor issue. The control unit had internal circuit board damage from moisture exposure. This affected both the ABS and stability control systems. The transmission control module was also getting faulty signals. The repair required: Full diagnostic scan, Replacement of the ABS control unit, Coding and adaptation of the new unit, System bleeding, Testing all speed sensors, Full system calibration This was a serious repair that took several days to complete properly. The odometer and basic speedometer functions worked because they operate on a separate circuit, but the stability systems were completely compromised. After fixing the control unit, all systems returned to normal operation including ABS function, traction control, and stability management. Would strongly recommend having a certified shop handle this repair due to the complexity of system integration and coding requirements.

Thanks for confirming it was the ABS control unit. Currently facing nearly identical symptoms on my Q7, warning lights, traction issues, everything you described. The transmission seems affected too, with some rough shifting. The diagnostic scan also points to the control unit. Just wondering, can you share what the total repair cost was for you? And has everything stayed working properly since the fix? A bit worried about other related issues popping up even after replacing the unit.

Thank you for asking about the follow-up results. Since having the control unit replaced, all ABS and transmission issues have completely resolved. The repair cost came to 1000 Euro total, including the diagnostic work, parts, and programming of the new unit. The dashboard warning lights disappeared immediately after the repair, and the traction control system now works flawlessly. The transmission shifting also returned to normal, as it was indeed getting incorrect input from the faulty ABS unit. Its been 8 months since the repair, and I have not experienced any related problems. The stability control and ABS systems continue to function as designed. The speed signal fault that was initially detected has not returned, confirming the control unit was the core issue. Just make sure the shop performs proper coding and calibration after installing the new unit. The diagnostic process should also verify all speed sensors are reading correctly once the new control unit is in place.

Updates on my ABS control unit situation, got it fixed last week and wanted to share the experience. The repair was pretty much exactly what was described. Took my Q7 to a certified shop after the local mechanic couldnt figure it out. The diagnostic scan confirmed a faulty ABS control unit causing the malfunction. The sensor inputs were all over the place according to the ECM logs. They replaced the unit, did the coding, and ran full system tests. Total bill came to 1200 Euro but at least everything is working properly now. The shop had to keep the car for 2 days to complete all the programming and testing. But the results were worth it, all warning lights are gone, traction control works perfectly again, and the transmission shifts smoothly. Really glad I didnt try any band-aid fixes since the odometer and speedometer were still working. Just finished a 200km trip in wet conditions and the ABS/stability systems performed flawlessly. No more white-knuckle moments when braking in the rain. Would definitely recommend getting the control unit replaced if anyone else runs into similar symptoms.