S5 Camshaft Sensor Issues Causing Stalling at Idle

Had similar symptoms with my 2015 Audi S4. The engine control module was logging multiple crankshaft sensor and camshaft position errors. The main issue turned out to be a damaged encoder wheel on the camshaft, causing incorrect ignition timing signals. The symptoms matched exactly, hard starts, unusual stalling at idle, and engine misfire codes. The sensor itself was functioning, but the encoder wheel teeth were worn, sending incorrect position data to the engine control unit. This is a serious issue that needs immediate attention, as continued driving risks further engine damage. The repair requires removing the camshaft cover to access the encoder wheel. The diagnostic process involves checking both the sensors and the encoder wheel teeth pattern with specialized equipment. A proper fix includes: Testing both camshaft position sensors, Inspecting encoder wheel condition, Verifying timing chain tension, Full system scan for related sensor failure codes This kind of issue requires specific diagnostic tools and expertise with Audi engine management systems. Suggest having it checked at a shop with certified Audi diagnostic equipment to properly identify the root cause.

Thanks for sharing those details on the encoder wheel issue. That really helps narrow down what I should look for. Since you dealt with something so similar, do you remember roughly how much the full repair ended up costing? Also curious if youve had any other sensor-related problems pop up since getting it fixed? Im trying to budget for the worst case and want to make sure I address everything while its in the shop to avoid repeat visits with the check engine light coming back on.

Following up on my earlier post, I got the encoder wheel issue fixed last month and the car runs perfectly now. The total repair came to 695 Euro, which included replacing the defective camshaft sensor and the worn encoder wheel. The check engine light hasnt returned since the repair. The mechanic confirmed my initial suspicion about the encoder wheel being the root cause of the engine misfire and stalling problems. They did a thorough check of the entire engine control system during the repair and found no other sensor issues. Its been about 5000km since the fix, and I havent experienced any more problems with hard starts or car stalling. The engine runs smoothly at idle now, and the acceleration response is back to normal. Getting both components replaced at once was definitely the right call, it prevented potential repeat visits for related sensor problems. If your symptoms match what I described, you might be looking at a similar repair cost. Just make sure they check both the sensor and the encoder wheel, since replacing just one might not solve the underlying issue.

Thanks for the input. I took my S5 to a different mechanic who specializes in engine management systems. The total bill came to 780 Euro, which included replacing both the camshaft position sensor and the encoder wheel, plus diagnostic time. The mechanic showed me the worn encoder wheel teeth when they removed it, pretty obvious why it was causing problems. They also did a full sensor testing routine and found no other issues. Car starts perfectly now and the check engine light is gone. The repair took about 5 hours total. The hardest part was waiting for the parts to arrive, but the actual fix was straightforward once they had everything. Really glad I caught this early before it caused more engine damage. Been driving for about 2 weeks since the repair, put on around 1000km, and everything works like new. No more stalling, no rough idle, and the engine feels much smoother overall. Definitely worth getting it properly diagnosed and fixed rather than trying quick fixes or ignoring the problem.