RS6 Exhaust Sensor Failure Triggers Limp Mode Crisis

Last month I experienced similar symptoms on my 2017 S6. The check engine light triggered when the temperature sensor started sending incorrect readings to the engine management system. The car exhaust system showed signs of a small leak near the connection points, which affected the temperature fluctuation readings. The repair involved replacing not just the faulty temperature sensor, but also addressing the exhaust component connection issue. A proper diagnosis revealed that the exhaust leak was causing irregular readings, making the engine compensate incorrectly. This explained both the limp mode activation and increased fuel consumption. The job was relatively serious since ignoring it could lead to catalytic converter damage and further engine performance issues. The repair required specialized diagnostic equipment to properly calibrate the new sensor with the engine management system. Important points to watch for: Make sure they check for exhaust leaks before just replacing the sensor, Request a complete diagnostic scan, Verify all exhaust mounting points are secure, Ensure they use OEM or high-quality equivalent sensors The whole process took about 4 hours at the shop, including diagnostic time and road testing to confirm proper operation.

Thanks for sharing your experience with the S6 heat sensor replacement. Your symptoms match what I went through with my RS6 last year. Just wondering, do you remember what was the total cost for fixing both the sensor and the exhaust system leak? Curious since prices seem to vary quite a bit between shops. Also, have you had any other engine management or exhaust component issues pop up since the repair was done?

Got the work completed last week and everything is running perfectly now. The faulty exhaust temperature sensor was the main culprit, just as suspected. The emission control system is working normally again after fixing both issues. The total cost came to 265 Euro for addressing both the heat sensor replacement and the exhaust system leak. This included parts, labor, and the required diagnostic work to properly calibrate the new sensor. Since the repair, no engine management warnings have appeared and fuel consumption has returned to normal levels. The exhaust sensor readings are now stable and the car runs at full power without going into limp mode. The mechanic did a thorough job checking all connection points in the exhaust system to prevent future leaks. Worth mentioning that using high-quality parts for the repair has made a noticeable difference in overall performance. The engine response is actually better than it was even before the issues started.

I took my RS6 to the shop yesterday and can confirm the diagnosis matched what others mentioned. The mechanic found the exhaust temperature sensor was failing, along with a small leak in the exhaust system that was messing with the readings. Total repair cost came to 890 Euro, which included: New temperature sensor, Exhaust component repairs, Full diagnostic scan, Labor and calibration The emission control system is now working perfectly and the car runs like new. No more limp mode or excessive fuel consumption. Really glad I got it fixed quickly before it could damage other components. Turned out the questionable repairs I mentioned earlier actually contributed to the exhaust system leak. The previous shop hadnt properly secured all the connection points. Current mechanic did a much more thorough job and checked every part of the system. Thanks for all the input, helped me know exactly what to look for during the repair process.