S5 Camshaft Sensor Failure Causing Engine Stalls

Had the same symptoms on my 2020 Audi S4. The stalling engine and rough idling turned out to be a failing camshaft position sensor, combined with a deteriorated wiring harness connection. The key warning signs you are describing match exactly: weak engine performance, difficult starting, and timing-related codes. These symptoms typically worsen over time, especially in cold weather when sensors are more stressed. The repair involved replacing both the camshaft sensor and the associated wiring harness. This is a serious issue that should not be postponed, as a malfunctioning sensor can cause the engine to stall unexpectedly while driving. The faulty readings between the camshaft and crankshaft positions can also cause timing issues that may damage engine components if left unaddressed. Most important signs to watch for: Engine hesitation during acceleration, Inconsistent idle speed, Check engine light flashing, Multiple failed start attempts This repair requires proper diagnostic equipment and expertise with engine timing systems. The job involves accessing components deep in the engine bay and ensuring precise sensor alignment during installation.

Thanks for sharing your experience. I had very similar timing issues and check engine alerts with my S5 last year. The engine misfire symptoms matched what you described, and the sensor failure ended up causing more problems than expected. After my dealer confirmed the diagnosis, they also found the wiring harness needed replacement due to heat damage. Did the repair last long for you? Would be great to know the total cost you paid and if any other issues came up since the fix.

Thanks for asking about the follow-up. I got the repair done and the timing issues were fully resolved. The mechanic found a damaged wire connection at the camshaft sensor, which was causing the erratic readings and check engine warnings. The fix was straightforward and cost 95 Euro to repair the faulty connection. No parts replacement was needed since the sensor itself was functioning correctly once properly connected. The rough idling and starting problems disappeared immediately after the repair. Its been 6 months since the fix, and I havent experienced any sensor failure or engine performance issues. The crankshaft and camshaft are now perfectly synchronized, and the engine runs smoothly without any warning lights or error codes. This turned out much simpler and cheaper than expected, especially since I initially feared needing a complete sensor and wiring harness replacement. Regular checks show everything is working as it should.

After getting lots of good advice here, I took my S5 to a certified dealer instead of my regular mechanic. They diagnosed the problem quickly, turned out the camshaft position sensor was failing and the wiring had some heat damage, just like others mentioned. The total repair came to 450 Euro, which included replacing both the sensor and damaged wiring harness. They completed everything in one day. The rough idling and starting problems disappeared right away. Its been about 2 weeks now, no check engine lights or error codes have returned. The engine runs much stronger now and starts perfectly every time. Really glad I caught this early before it could cause any serious damage to the timing system. Going to stick with this dealer for future repairs, they even showed me the worn parts and explained exactly what was wrong.