Audi S7 Camshaft Sensor Issues Killing Performance

As someone with moderate experience working on cars, I had a very similar issue with my 2016 Audi S6. The symptoms you describe match exactly what I experienced, poor starting, reduced power, and error codes related to the camshaft position sensor. After experiencing stalling engine problems and rough idling, I took it to a workshop. The diagnostic revealed a faulty connection between the camshaft sensor and its wiring harness. The automotive sensor itself was fine, but the cable connection had degraded over time. The total repair cost was 95 Euro, which covered the labor to access the sensor location, clean the connections, and repair the wiring. The whole job took about 2 hours. Since the repair, the engine has been running perfectly with no sensor failure issues. Before suggesting specific solutions, could you share: The exact error codes from your diagnostic tool, Whether the check engine light is constantly on or intermittent, If the problems occur more frequently when the engine is cold or warm, The current mileage of your S7 This information would help determine if your issue is truly similar to what I experienced with the camshaft sensor wiring.

Thanks for the helpful replies. My vehicle has 149922 KM on the odometer, and I had the last service done at a specialist 3 months ago. The check engine light is constant, and the issues are definitely worse when the engine is cold. The diagnostic tool shows P0340 and P0341 codes, which apparently relate to the camshaft position sensor circuit range and performance. The crankshaft sensor readings look normal in the live data. Based on the information shared, this seems quite similar to the wiring issue mentioned. The timing of the engine misfire symptoms, especially during cold starts, matches perfectly with what others have described for sensor failure problems. Have others found that replacing just the wiring harness was sufficient, or did the entire sensor assembly need replacement?

Thanks for providing those details. The error codes P0340/P0341 combined with cold start issues on your S7 are exactly what I encountered with my S6 before fixing it. However, my initial diagnosis about just the wiring being the culprit turned out to be incomplete. In my case, while the wiring harness showed signs of wear, the camshaft sensor itself had also degraded. The timing issues and engine misfire symptoms persisted even after repairing just the wiring. I ended up needing to replace both the sensor and harness as a complete assembly. The full repair included: New camshaft position sensor assembly (320 Euro), Labor costs (180 Euro), System diagnostic and reset (60 Euro) Total repair time was about 4 hours. The stalling engine problems disappeared immediately after replacement, and cold starts have been perfect since. If your symptoms and error codes match mine this closely, I would recommend replacing the entire assembly rather than trying to fix just the wiring to avoid repeated issues. Since you mentioned the crankshaft sensor readings are normal, this further confirms the camshaft sensor as the likely culprit. These sensor failure issues often show up around 150000 KM on these models, so your mileage fits the typical pattern.

Thanks everyone for the detailed responses. After comparing my symptoms with similar cases, I feel more confident about the diagnosis. The timing issues and error codes definitely point to the camshaft sensor assembly being the problem. I called a few shops and got quotes ranging from 500 Euro to 650 Euro for a complete sensor and harness replacement. Given that my rough idling gets worse during cold starts and the check engine light remains constant, I will go ahead with the full replacement rather than just attempting a wiring repair. Will schedule the repair next week and update once it is done. The stalling engine and performance problems have become too annoying to postpone any longer, especially with the cold weather approaching. Hopefully, replacing both the automotive sensor and wiring harness will resolve these issues completely, as it did for others with similar symptoms.