Audi Q5 Exhaust Leak + Engine Trouble Warning Signs

Had similar issues with my 2011 Audi A4 2.0T. The symptoms match exactly what I experienced, rough engine performance, strong exhaust odor, and persistent engine light. The root cause was a failed oxygen sensor combined with a small exhaust leak near the manifold. The diagnosis revealed multiple connected issues. Initial scan showed oxygen sensor malfunction, but further inspection found the exhaust leak was allowing unmetered air into the system, throwing off engine management readings. This caused the engine to run rich, leading to poor performance and that distinctive smell. The comprehensive fix required: Replacing faulty oxygen sensor, Repairing exhaust leak, Clearing system codes, Performing readiness tests This was a serious issue requiring immediate attention, as continued operation could damage the catalytic converter. After repairs, engine performance returned to normal, exhaust smell disappeared, and the engine light cleared permanently. For your Q5, strongly recommend finding a specialist who can properly diagnose the full extent of the problem. These symptoms often indicate connected issues rather than a single fault. The exhaust leak you noticed might be masking other problems in the emissions control system.

Thanks for sharing your experience. This is very similar to what my Q5 is going through right now. The oxygen sensor and exhaust leak combination makes perfect sense given the symptoms. Just wondering, do you remember roughly how much the total repair cost you? Also, has everything stayed working properly since the fix? The engine light in mine recently started flickering before staying on permanently, and Im also noticing the exhaust problem seems worse during cold starts. Just trying to get an idea if I should prepare for any additional repairs beyond the obvious exhaust and sensor issues.

Good to update you on the outcome. My repair experience ended up being straightforward after the Lambda sensor replacement. The exhaust treatment malfunction warning cleared completely once the new sensor was installed and calibrated. Total cost came to 375 Euro for parts and labor. The flickering check engine light you mentioned is typical with failing sensors, so that matches the diagnosis. Since the repair, my engine runs smoothly with no warning lights or exhaust issues, even during cold starts. The key was catching it before the faulty sensor could damage the catalytic converter or trigger broader EGR valve problems. A bad sensor can cause the engine to run rich, which risks expensive damage to other exhaust components if left unchecked. Based on the price I paid and your similar symptoms, you should find the repair costs comparable, assuming the exhaust leak is minor and the catalytic converter hasnt been compromised. The most important thing is addressing it promptly to prevent cascading issues in the exhaust system.

I found a specialist shop last week and got everything sorted. The diagnosis matched what you described, failed oxygen sensor causing rich fuel mixture, plus a cracked exhaust pipe near the manifold. The total repair came to 420 Euro, which included: New oxygen sensor, Welding the exhaust leak, Full system diagnostic, Labor costs The particulate filter showed early signs of clogging from the rich mixture, but cleaning it was enough rather than replacement. The mechanic explained how the bad sensor readings were making the engine dump extra fuel, which was causing that strong exhaust smell. Everything runs perfectly now. No more check engine light, smooth idle, and the exhaust smell is completely gone. Cold starts are back to normal too. Really glad I caught this before it could damage the catalytic converter. Thanks again for helping point me in the right direction with the diagnosis. The shop confirmed multiple connected issues was exactly the problem, just like you suggested.