Audi S5 NOx Sensor Issues Trigger Emission Faults

Having some experience with diesel engines, I dealt with a similar issue on my 2020 Audi A5. The check engine light and pollution control warnings were almost identical to what you describe. After initial diagnostics, the workshop found that the NOx sensor had a damaged cable connection, which was causing erratic readings in the air-fuel ratio. The exhaust leaks you mentioned often accompany these sensor issues because the system tries to compensate for incorrect readings. The fix was straightforward but required specialized diagnostic equipment. The total repair cost was 95 Euro, covering the reconnection and testing. The workshop also performed a complete system reset to clear the error codes. To provide more specific guidance about your S5, could you share: Current mileage, When the check engine light first appeared, Any performance changes noticed, Whether the issue occurs more during cold starts, If you have access to diagnostic codes Worth noting that while the symptoms sound similar, the S5 has a different engine configuration than my A5, so the exact repair approach might vary.

Having some experience with diesel engines, I dealt with a similar issue on my 2020 Audi A5. The check engine light and pollution control warnings were almost identical to what you describe. After initial diagnostics, the workshop found that the NOx sensor had a damaged cable connection, which was causing erratic readings in the air-fuel ratio. The exhaust leaks you mentioned often accompany these sensor issues because the system tries to compensate for incorrect readings. The fix was straightforward but required specialized diagnostic equipment. The total repair cost was 95 Euro, covering the reconnection and testing. The workshop also performed a complete system reset to clear the error codes. To provide more specific guidance about your S5, could you share: Current mileage, When the check engine light first appeared, Any performance changes noticed, Whether the issue occurs more during cold starts, If you have access to diagnostic codes Worth noting that while the symptoms sound similar, the S5 has a different engine configuration than my A5, so the exact repair approach might vary.

Having some experience with diesel engines, I dealt with a similar issue on my 2020 Audi A5. The check engine light and pollution control warnings were almost identical to what you describe. After initial diagnostics, the workshop found that the NOx sensor had a damaged cable connection, which was causing erratic readings in the air-fuel ratio. The exhaust leaks you mentioned often accompany these sensor issues because the system tries to compensate for incorrect readings. The fix was straightforward but required specialized diagnostic equipment. The total repair cost was 95 Euro, covering the reconnection and testing. The workshop also performed a complete system reset to clear the error codes. To provide more specific guidance about your S5, could you share: Current mileage, When the check engine light first appeared, Any performance changes noticed, Whether the issue occurs more during cold starts, If you have access to diagnostic codes Worth noting that while the symptoms sound similar, the S5 has a different engine configuration than my A5, so the exact repair approach might vary.

Thanks for the detailed input. My S5 has only 14715 KM and had its last service 2 months ago. The check engine light started appearing right after a cold start last week. The catalytic converter seems to work fine based on exhaust readings, but the nitrogen oxide levels are inconsistent. Ive noticed slightly reduced power output, especially during acceleration. The diagnostic codes point to the emission sensor system, but the readings are intermittent. Given the low mileage and recent service, Im wondering if this could be a warranty case.

Thanks for the detailed input. My S5 has only 14715 KM and had its last service 2 months ago. The check engine light started appearing right after a cold start last week. The catalytic converter seems to work fine based on exhaust readings, but the nitrogen oxide levels are inconsistent. Ive noticed slightly reduced power output, especially during acceleration. The diagnostic codes point to the emission sensor system, but the readings are intermittent. Given the low mileage and recent service, Im wondering if this could be a warranty case.

Thanks for the detailed input. My S5 has only 14715 KM and had its last service 2 months ago. The check engine light started appearing right after a cold start last week. The catalytic converter seems to work fine based on exhaust readings, but the nitrogen oxide levels are inconsistent. Ive noticed slightly reduced power output, especially during acceleration. The diagnostic codes point to the emission sensor system, but the readings are intermittent. Given the low mileage and recent service, Im wondering if this could be a warranty case.

Thanks for providing those details. Just like with my A5, intermittent sensor readings often indicate either a wiring issue or sensor degradation. The lower power output you mentioned mirrors what I experienced, especially when the NOx sensor started malfunctioning. Given your low mileage and recent service, this absolutely should be covered under warranty. When my emission sensor system showed similar symptoms, even though my car had higher mileage, the diagnostic pattern was nearly identical. The inconsistent nitrogen oxide readings are particularly telling, its a classic sign of a NOx sensor failure. The diesel engine pollution control systems are quite sensitive, and even minor issues can trigger these symptoms. In my case, the intermittent nature of the problem made diagnosis tricky, but the reduced power during acceleration was a key indicator that helped pinpoint the emission sensor as the culprit. Strongly recommend getting this checked under warranty rather than waiting. The pollution control system in these models can develop more serious issues if sensor problems are left unaddressed. Document the cold start incidents and performance changes, this will help support your warranty claim.

Thanks for providing those details. Just like with my A5, intermittent sensor readings often indicate either a wiring issue or sensor degradation. The lower power output you mentioned mirrors what I experienced, especially when the NOx sensor started malfunctioning. Given your low mileage and recent service, this absolutely should be covered under warranty. When my emission sensor system showed similar symptoms, even though my car had higher mileage, the diagnostic pattern was nearly identical. The inconsistent nitrogen oxide readings are particularly telling, its a classic sign of a NOx sensor failure. The diesel engine pollution control systems are quite sensitive, and even minor issues can trigger these symptoms. In my case, the intermittent nature of the problem made diagnosis tricky, but the reduced power during acceleration was a key indicator that helped pinpoint the emission sensor as the culprit. Strongly recommend getting this checked under warranty rather than waiting. The pollution control system in these models can develop more serious issues if sensor problems are left unaddressed. Document the cold start incidents and performance changes, this will help support your warranty claim.

Thanks for providing those details. Just like with my A5, intermittent sensor readings often indicate either a wiring issue or sensor degradation. The lower power output you mentioned mirrors what I experienced, especially when the NOx sensor started malfunctioning. Given your low mileage and recent service, this absolutely should be covered under warranty. When my emission sensor system showed similar symptoms, even though my car had higher mileage, the diagnostic pattern was nearly identical. The inconsistent nitrogen oxide readings are particularly telling, its a classic sign of a NOx sensor failure. The diesel engine pollution control systems are quite sensitive, and even minor issues can trigger these symptoms. In my case, the intermittent nature of the problem made diagnosis tricky, but the reduced power during acceleration was a key indicator that helped pinpoint the emission sensor as the culprit. Strongly recommend getting this checked under warranty rather than waiting. The pollution control system in these models can develop more serious issues if sensor problems are left unaddressed. Document the cold start incidents and performance changes, this will help support your warranty claim.

Thanks everyone for the great insights. Really appreciate the detailed feedback, especially about the warranty coverage potential. I will definitely document all symptoms before heading to the workshop. Just booked an appointment for next week and made sure to mention all the details discussed here, the cold start issues, intermittent NOx sensor readings, and the power loss during acceleration. The service advisor confirmed theyll check the diesel engine emissions system thoroughly, particularly focusing on the pollution control components and wiring connections. Still hoping its just a sensor issue rather than something more complex with the catalytic system. Will update once I get the diagnosis and repairs completed. Good to know others have successfully resolved similar check engine light problems. The specific details about diagnostic patterns and repair processes shared here will help ensure I get the right fix under warranty.

Thanks everyone for the great insights. Really appreciate the detailed feedback, especially about the warranty coverage potential. I will definitely document all symptoms before heading to the workshop. Just booked an appointment for next week and made sure to mention all the details discussed here, the cold start issues, intermittent NOx sensor readings, and the power loss during acceleration. The service advisor confirmed theyll check the diesel engine emissions system thoroughly, particularly focusing on the pollution control components and wiring connections. Still hoping its just a sensor issue rather than something more complex with the catalytic system. Will update once I get the diagnosis and repairs completed. Good to know others have successfully resolved similar check engine light problems. The specific details about diagnostic patterns and repair processes shared here will help ensure I get the right fix under warranty.

Thanks everyone for the great insights. Really appreciate the detailed feedback, especially about the warranty coverage potential. I will definitely document all symptoms before heading to the workshop. Just booked an appointment for next week and made sure to mention all the details discussed here, the cold start issues, intermittent NOx sensor readings, and the power loss during acceleration. The service advisor confirmed theyll check the diesel engine emissions system thoroughly, particularly focusing on the pollution control components and wiring connections. Still hoping its just a sensor issue rather than something more complex with the catalytic system. Will update once I get the diagnosis and repairs completed. Good to know others have successfully resolved similar check engine light problems. The specific details about diagnostic patterns and repair processes shared here will help ensure I get the right fix under warranty.