Audi SQ5: Rough Engine + Exhaust Leak After Poor Repair

A similar issue occurred with my 2012 Audi S4 (3.0 TFSI). The symptoms match exactly what you describe, rough running, check engine light, and exhaust fumes. The diagnostic revealed a failed Lambda sensor combined with a cracked exhaust pipe near the manifold. The Lambda sensor failure caused incorrect fuel mixture readings, leading to poor engine performance and increased emissions. The exhaust leak made it worse by allowing false readings to reach the NOx sensors, creating a cycle of incorrect engine management. This needs immediate attention as it can lead to: Catalytic converter damage, Increased fuel consumption, Potential engine damage if left untreated, Failed emissions tests The repair requires: 1. Complete diagnostic scan 2. Lambda sensor replacement 3. Exhaust pipe inspection and repair 4. System reset and adaptation This is considered a serious repair as it affects both engine performance and emissions control systems. The exhaust leak especially needs immediate attention as it can lead to harmful gases entering the cabin. For proper diagnosis, a professional workshop with Audi-specific diagnostic equipment is essential. The combination of symptoms suggests multiple related issues rather than a single faulty component.

A similar issue occurred with my 2012 Audi S4 (3.0 TFSI). The symptoms match exactly what you describe, rough running, check engine light, and exhaust fumes. The diagnostic revealed a failed Lambda sensor combined with a cracked exhaust pipe near the manifold. The Lambda sensor failure caused incorrect fuel mixture readings, leading to poor engine performance and increased emissions. The exhaust leak made it worse by allowing false readings to reach the NOx sensors, creating a cycle of incorrect engine management. This needs immediate attention as it can lead to: Catalytic converter damage, Increased fuel consumption, Potential engine damage if left untreated, Failed emissions tests The repair requires: 1. Complete diagnostic scan 2. Lambda sensor replacement 3. Exhaust pipe inspection and repair 4. System reset and adaptation This is considered a serious repair as it affects both engine performance and emissions control systems. The exhaust leak especially needs immediate attention as it can lead to harmful gases entering the cabin. For proper diagnosis, a professional workshop with Audi-specific diagnostic equipment is essential. The combination of symptoms suggests multiple related issues rather than a single faulty component.

A similar issue occurred with my 2012 Audi S4 (3.0 TFSI). The symptoms match exactly what you describe, rough running, check engine light, and exhaust fumes. The diagnostic revealed a failed Lambda sensor combined with a cracked exhaust pipe near the manifold. The Lambda sensor failure caused incorrect fuel mixture readings, leading to poor engine performance and increased emissions. The exhaust leak made it worse by allowing false readings to reach the NOx sensors, creating a cycle of incorrect engine management. This needs immediate attention as it can lead to: Catalytic converter damage, Increased fuel consumption, Potential engine damage if left untreated, Failed emissions tests The repair requires: 1. Complete diagnostic scan 2. Lambda sensor replacement 3. Exhaust pipe inspection and repair 4. System reset and adaptation This is considered a serious repair as it affects both engine performance and emissions control systems. The exhaust leak especially needs immediate attention as it can lead to harmful gases entering the cabin. For proper diagnosis, a professional workshop with Audi-specific diagnostic equipment is essential. The combination of symptoms suggests multiple related issues rather than a single faulty component.

A similar issue occurred with my 2012 Audi S4 (3.0 TFSI). The symptoms match exactly what you describe, rough running, check engine light, and exhaust fumes. The diagnostic revealed a failed Lambda sensor combined with a cracked exhaust pipe near the manifold. The Lambda sensor failure caused incorrect fuel mixture readings, leading to poor engine performance and increased emissions. The exhaust leak made it worse by allowing false readings to reach the NOx sensors, creating a cycle of incorrect engine management. This needs immediate attention as it can lead to: Catalytic converter damage, Increased fuel consumption, Potential engine damage if left untreated, Failed emissions tests The repair requires: 1. Complete diagnostic scan 2. Lambda sensor replacement 3. Exhaust pipe inspection and repair 4. System reset and adaptation This is considered a serious repair as it affects both engine performance and emissions control systems. The exhaust leak especially needs immediate attention as it can lead to harmful gases entering the cabin. For proper diagnosis, a professional workshop with Audi-specific diagnostic equipment is essential. The combination of symptoms suggests multiple related issues rather than a single faulty component.

Thanks for sharing your experience. I had the same problem with my SQ5 about 8 months ago. The oxygen sensor was indeed the main culprit, but during inspection they also found a small crack in the exhaust pipe. Getting both fixed resolved all the issues, and my engine has been running smoothly since. Would you mind sharing what you ended up paying for the repairs? Also curious if you encountered any other issues since getting it fixed? My repair bill was quite steep and Id like to compare notes.

Thanks for sharing your experience. I had the same problem with my SQ5 about 8 months ago. The oxygen sensor was indeed the main culprit, but during inspection they also found a small crack in the exhaust pipe. Getting both fixed resolved all the issues, and my engine has been running smoothly since. Would you mind sharing what you ended up paying for the repairs? Also curious if you encountered any other issues since getting it fixed? My repair bill was quite steep and Id like to compare notes.

Thanks for sharing your experience. I had the same problem with my SQ5 about 8 months ago. The oxygen sensor was indeed the main culprit, but during inspection they also found a small crack in the exhaust pipe. Getting both fixed resolved all the issues, and my engine has been running smoothly since. Would you mind sharing what you ended up paying for the repairs? Also curious if you encountered any other issues since getting it fixed? My repair bill was quite steep and Id like to compare notes.

Thanks for sharing your experience. I had the same problem with my SQ5 about 8 months ago. The oxygen sensor was indeed the main culprit, but during inspection they also found a small crack in the exhaust pipe. Getting both fixed resolved all the issues, and my engine has been running smoothly since. Would you mind sharing what you ended up paying for the repairs? Also curious if you encountered any other issues since getting it fixed? My repair bill was quite steep and Id like to compare notes.

Good to hear you got it sorted. Had mine fixed last month and the exhaust treatment malfunction warning finally disappeared. The Lambda sensor replacement cost me 375 Euro at a specialized workshop. This resolved all the issues, including the engine light and rough running. Like yours, my engine runs perfectly smooth now. The diagnostic confirmed the failed Lambda sensor was causing incorrect readings and messing with the NOx sensors. Since the repair, I have not experienced any related problems or warning lights. The fuel consumption has also improved noticeably. The cost seems in line with what these repairs typically go for, especially considering the specialized diagnostic equipment needed. Much better to fix it properly than risk damage to the particulate filter or EGR valve down the line.

Good to hear you got it sorted. Had mine fixed last month and the exhaust treatment malfunction warning finally disappeared. The Lambda sensor replacement cost me 375 Euro at a specialized workshop. This resolved all the issues, including the engine light and rough running. Like yours, my engine runs perfectly smooth now. The diagnostic confirmed the failed Lambda sensor was causing incorrect readings and messing with the NOx sensors. Since the repair, I have not experienced any related problems or warning lights. The fuel consumption has also improved noticeably. The cost seems in line with what these repairs typically go for, especially considering the specialized diagnostic equipment needed. Much better to fix it properly than risk damage to the particulate filter or EGR valve down the line.

Good to hear you got it sorted. Had mine fixed last month and the exhaust treatment malfunction warning finally disappeared. The Lambda sensor replacement cost me 375 Euro at a specialized workshop. This resolved all the issues, including the engine light and rough running. Like yours, my engine runs perfectly smooth now. The diagnostic confirmed the failed Lambda sensor was causing incorrect readings and messing with the NOx sensors. Since the repair, I have not experienced any related problems or warning lights. The fuel consumption has also improved noticeably. The cost seems in line with what these repairs typically go for, especially considering the specialized diagnostic equipment needed. Much better to fix it properly than risk damage to the particulate filter or EGR valve down the line.

Good to hear you got it sorted. Had mine fixed last month and the exhaust treatment malfunction warning finally disappeared. The Lambda sensor replacement cost me 375 Euro at a specialized workshop. This resolved all the issues, including the engine light and rough running. Like yours, my engine runs perfectly smooth now. The diagnostic confirmed the failed Lambda sensor was causing incorrect readings and messing with the NOx sensors. Since the repair, I have not experienced any related problems or warning lights. The fuel consumption has also improved noticeably. The cost seems in line with what these repairs typically go for, especially considering the specialized diagnostic equipment needed. Much better to fix it properly than risk damage to the particulate filter or EGR valve down the line.

Thanks for the input. Just wanted to close the loop on this one. Finally took my car to a different mechanic who specializes in German cars. The diagnostic showed exactly what was suspected, a faulty oxygen sensor and a small crack in the exhaust pipe near the manifold. Total repair came to 850 Euro, the oxygen sensor replacement was 375 Euro and the exhaust pipe repair cost 475 Euro. The engine light disappeared immediately after the fix and the rough running is completely gone. The exhaust smell has also cleared up. The mechanic also cleaned the EGR valve while they were at it, saying it had quite a bit of carbon buildup. No extra charge for that, which was nice. The car runs better than ever now, and fuel economy has improved significantly. Much happier with this mechanic, they took the time to show me the damaged parts and explain everything. Should have switched shops sooner. Good lesson learned about finding the right specialist for these kinds of repairs.

Thanks for the input. Just wanted to close the loop on this one. Finally took my car to a different mechanic who specializes in German cars. The diagnostic showed exactly what was suspected, a faulty oxygen sensor and a small crack in the exhaust pipe near the manifold. Total repair came to 850 Euro, the oxygen sensor replacement was 375 Euro and the exhaust pipe repair cost 475 Euro. The engine light disappeared immediately after the fix and the rough running is completely gone. The exhaust smell has also cleared up. The mechanic also cleaned the EGR valve while they were at it, saying it had quite a bit of carbon buildup. No extra charge for that, which was nice. The car runs better than ever now, and fuel economy has improved significantly. Much happier with this mechanic, they took the time to show me the damaged parts and explain everything. Should have switched shops sooner. Good lesson learned about finding the right specialist for these kinds of repairs.

Thanks for the input. Just wanted to close the loop on this one. Finally took my car to a different mechanic who specializes in German cars. The diagnostic showed exactly what was suspected, a faulty oxygen sensor and a small crack in the exhaust pipe near the manifold. Total repair came to 850 Euro, the oxygen sensor replacement was 375 Euro and the exhaust pipe repair cost 475 Euro. The engine light disappeared immediately after the fix and the rough running is completely gone. The exhaust smell has also cleared up. The mechanic also cleaned the EGR valve while they were at it, saying it had quite a bit of carbon buildup. No extra charge for that, which was nice. The car runs better than ever now, and fuel economy has improved significantly. Much happier with this mechanic, they took the time to show me the damaged parts and explain everything. Should have switched shops sooner. Good lesson learned about finding the right specialist for these kinds of repairs.

Thanks for the input. Just wanted to close the loop on this one. Finally took my car to a different mechanic who specializes in German cars. The diagnostic showed exactly what was suspected, a faulty oxygen sensor and a small crack in the exhaust pipe near the manifold. Total repair came to 850 Euro, the oxygen sensor replacement was 375 Euro and the exhaust pipe repair cost 475 Euro. The engine light disappeared immediately after the fix and the rough running is completely gone. The exhaust smell has also cleared up. The mechanic also cleaned the EGR valve while they were at it, saying it had quite a bit of carbon buildup. No extra charge for that, which was nice. The car runs better than ever now, and fuel economy has improved significantly. Much happier with this mechanic, they took the time to show me the damaged parts and explain everything. Should have switched shops sooner. Good lesson learned about finding the right specialist for these kinds of repairs.