Audi S1 Stalling Issue Points to Faulty Cam Sensor

Had similar issues with my 2013 Audi S3. With some experience working on cars, I initially thought it was just a camshaft sensor failure, but the actual problem turned out to be more specific. The symptoms matched exactly what you describe, rough starts, stalling at idle, and check engine light. After sensor testing at my regular workshop, they discovered the encoder wheel on the camshafts was defective, causing incorrect camshaft position readings. This explained why the engine management was getting confused about valve timing. The total repair came to 695 Euro, including parts and labor. The fix involved replacing both the encoder wheel and camshaft sensor as a precaution, since they work as a system. After the repair, the engine ran perfectly again. Could you share some additional details about your S1: Any specific error codes from the check engine light? Does the problem get worse when the engine is warm or cold? Have you noticed any unusual sounds from the top of the engine? What's your current mileage? This information would help confirm if your issue matches what I experienced with my S3. A proper diagnosis through crankshaft sensor and camshaft position monitoring would be the best way to confirm the exact problem.

Thanks for sharing your experience. My last service was actually 2 months ago, and with 89664 KM on the clock, no issues were found then. The engine control unit is now showing error code P0340, which points toward a camshaft position sensor issue. The problem definitely gets worse when the engine is warm, and I can hear a slight ticking noise from the valve cover area. I had the ignition timing checked by a friend with a diagnostic tool, and the readings were inconsistent, suggesting a sensor failure somewhere in the system. Good to know about the encoder wheel, I will have that checked along with the sensor. The repair cost you mentioned seems reasonable compared to what I was quoted.

Thanks for providing those additional details. Your error code P0340 and symptoms match my S3 case exactly, especially the ticking noise and timing inconsistencies when warm. The encoder wheel issue on these engines often develops around 80-90k km, which aligns with your mileage. The check engine light and engine misfire patterns you describe are classic signs of this problem in our engines. After my repair, I learned these camshaft sensor issues can be tricky because the sensor itself might test fine, but the encoder wheel wear causes erratic readings. When the engine control unit receives these inconsistent signals, it cant properly adjust valve timing, leading to the stalling you experience. Quick tip from my experience: while they are replacing parts, have them check the wiring harness connected to the sensor. Mine had some wear that could have caused future problems if not addressed during the repair. Worth noting that driving with these symptoms risks further engine damage, as incorrect timing can affect valve operation. Would recommend getting it looked at soon, and make sure they specifically check both the sensor and encoder wheel rather than just replacing the sensor alone.

Thanks everyone for the detailed responses. After reading about your experiences, especially regarding the encoder wheel issue, I feel much more confident about the repair direction. Just wanted to update that I took the car to a workshop yesterday. They confirmed both a sensor failure and worn encoder wheel, exactly as suggested here. The total repair came to 720 Euro, slightly higher than expected but worth it given they found and fixed some wiring issues too. The engine now runs perfectly, no more stalling, check engine light is off, and the ignition timing is spot on. Really glad I asked here before going in blind, as I might have ended up paying for just a sensor replacement which wouldnt have solved the underlying problem. For anyone searching with similar symptoms in the future: definitely get both the camshaft sensor and encoder wheel checked if you have rough starts and engine misfire issues. The repair cost might be higher than a simple sensor replacement, but it properly fixes the problem.