Audi S7 NOx Sensor Linked to Exhaust Leak Alert

Had a similar issue with my 2012 Audi S6 last month. The check engine light was triggered by a failing emission sensor, which was causing incorrect readings in the exhaust system. The main symptoms matched yours, check engine light and exhaust leak sounds. After scanning, it turned out the NOx sensor wiring had deteriorated, causing intermittent connection issues. The catalytic converter was functioning properly, but the faulty sensor was making the system think otherwise. The fix required replacing the NOx sensor and repairing the wiring harness connection. This was not a major repair, but leaving it unfixed could lead to catalytic converter damage over time. The sensor failure is somewhat common in these engines after 70000-80000 km. Important to note: A proper diagnostic scan will show if its truly the NOx sensor or potentially other exhaust system components. The error codes should point specifically to sensor-related issues rather than mechanical exhaust problems. Would recommend getting it checked soon, as faulty readings can affect engine performance and potentially cause more expensive repairs if left unaddressed.

Thanks for sharing your experience with the NOx sensor issue. This helps confirm what I was suspecting. How much did your repair end up costing? I am planning to get it fixed this week since I do not want to risk damaging the pollution control system further. Also curious if you have experienced any other check engine warnings or exhaust system problems since the repair?

Great to hear back from you. The NOx sensor repair was straightforward and cost-effective at 95 Euro for fixing the cable connection issue. The mechanic found the plug connection was defective, causing those faulty readings in the air-fuel ratio monitoring system. Since the repair, my diesel engine has been running smoothly with no further check engine warnings. The pollution control system is working as intended, and I have not experienced any additional exhaust system problems. The repair completely resolved the intermittent sensor readings that were causing the initial warnings. Regular monitoring of the NOx sensor performance is important for maintaining proper emission control, but once fixed correctly, these issues rarely return. The catalytic converter continues working efficiently now that it receives accurate sensor data. I made the right choice getting it fixed quickly, and it sounds like you are too. Acting fast helps prevent more extensive damage to the emission control components.

Thank you everyone for the input. I took my car to a certified mechanic today who specializes in diesel engine systems. The diagnostic confirmed it was indeed the NOx sensor causing the check engine light and exhaust issues. The total repair came to 280 Euro which included replacing the faulty sensor and fixing some corroded wiring in the pollution control system. They completed everything in about 3 hours. Since the repair, the exhaust leak sound is completely gone and no more warning lights. The catalytic converter was tested and is working properly. Really glad I addressed this quickly before it could cause more extensive damage. For anyone facing similar issues, getting a proper diagnostic scan first saved me from unnecessary repairs. Sometimes the simplest solution is the right one.