Audi Q7 Engine Stalls: Camshaft Sensor Alert

I experienced similar issues with my Audi Q5 3.0T from 2012. Having some experience with engine control systems, those symptoms immediately reminded me of what I went through. The engine misfire and stalling issues turned out to be related to a defective encoder wheel on the camshafts, which directly affects camshaft position sensing and ignition timing. The workshop diagnosed it using specialized diagnostic equipment to monitor the cam sensor signals. The repair involved replacing the faulty encoder wheel and recalibrating the engine control system. Total cost was 695 Euro including parts and labor. After the fix, the engine ran smoothly again with no more cold start issues or stalling problems. To better assist with your specific case, could you share: Current mileage on your Q7, Whether the check engine light is constant or flickering, If you notice the issues more during cold or warm weather, Any specific error codes if you have had them read These details would help determine if your symptoms align with what I experienced and could point to similar root causes in the camshaft position system.

Thanks for sharing your experience. My Q7 has 71119 KM and was last serviced 3 months ago. The check engine light stays constant, not flickering. I had the codes read at a local shop, they showed P0340 and P0016, which apparently relate to the camshaft position sensor circuit and timing correlation issues. I noticed my symptoms match yours closely. The cold start misfires and stalling are particularly bad during cold mornings. After researching further, I think the encoder wheel issue you mentioned makes sense, especially given the error codes pointing to crankshaft sensor and camshaft position problems. Before booking a workshop appointment, is there anything specific I should ask them to inspect besides the encoder wheel and ignition timing components?

Those error codes P0340 and P0016 definitely point towards camshaft sensor failure or timing correlation issues, which matches my experience. The workshop found my encoder wheel had worn significantly, affecting the camshaft sensor readings and causing engine control problems. Given your mileage and symptoms, I recommend having them check the entire timing chain system while they diagnose the camshaft position sensor. On my Q5, they discovered slight timing chain wear that contributed to the timing correlation issues. The sensor testing revealed inconsistent signals due to both the encoder wheel wear and timing chain stretch. The complete repair on my vehicle included: Diagnostic testing of camshaft sensors, Encoder wheel replacement, Timing chain inspection, Engine control system recalibration Total repair time was about 6 hours. If they find similar issues, expect costs between 650-850 Euro depending on parts needed. Make sure they check all related wiring connections too, as poor connections can mimic sensor failure symptoms. The check engine light cleared after repairs and never returned. Cold starts have been perfect since, even in freezing temperatures.

Thanks for those details. Based on your second reply, I will definitely mention both the encoder wheel and timing chain inspection when I take it in. Your repair experience is really helpful since the error codes and symptoms match so closely with what I had. I called a certified workshop and scheduled an appointment for next week. They quoted 1 hour for initial diagnostic testing of the camshaft position sensor and related components. I specifically asked them to inspect the encoder wheel and timing chain system as you suggested, since engine misfire symptoms seem to point in that direction. The service advisor mentioned they often see these exact symptoms when there is a combination of sensor failure and mechanical wear in the timing components. They estimated around 750 Euro for a complete repair if they find similar issues to yours. Will update once I get the car diagnosed and repaired. Really appreciate the detailed breakdown of your repair process, it helped me understand what to expect and ask for at the workshop.