Audi Q3 Cam Sensor Issue Causes Power Loss

I had a very similar issue with my 2013 Audi Q5 last year, and having some experience with engine management issues, I can probably help. The symptoms you describe match exactly what I experienced, the engine light came on, performance dropped significantly, and fuel consumption went through the roof. After running diagnostics, it turned out the crankshaft sensor was defective, causing incorrect engine synchronization readings. The workshop first checked the timing chain and related components, but they were all fine. The real problem was identified when they tested the crank sensor signals, the reference values were completely off, causing the engine management system to receive incorrect timing data. The fix involved: Complete diagnostic scan, Testing of sensor signals, Replacement of the faulty crank sensor, System reset and adaptation Total cost in my case was 340 Euro, including parts and labor. The repair solved all issues immediately, engine light went off, performance returned to normal, and fuel consumption improved. Before suggesting more specific advice, could you share: What error codes are you getting? Has the timing chain ever been replaced? Are you experiencing any unusual engine sounds? What mileage is on your Q3? This information would help determine if your issue is identical to what I experienced.

Last service done at 122000 KM, currently showing 124011 KM. Based on diagnostic reports from my mechanic, error codes point to timing-related issues. The camshaft position sensor shows inconsistent readings when compared to crank sensor data. The timing chain has never been replaced and runs without noise. My mechanic suggests replacing both the crank sensor and camshaft sensor as a precautionary measure since engine synchronization readings show both sensors giving unreliable reference values. They quoted 460 Euro for parts and labor. Think I will proceed with the repair since the symptoms match the diagnosis and the cost seems reasonable for the potential fix of these issues.

Definitely agree with your mechanic's approach, replacing both sensors is smart preventive maintenance. When I had my Q5 fixed, I initially only replaced the crankshaft sensor, but 3 months later the camshaft sensor failed with similar symptoms. Had to pay for labor twice, which was frustrating. The reference values between crankshaft and camshaft need to be perfectly synchronized for proper engine operation. When either sensor starts failing, it disrupts engine synchronization and throws off timing. Your mileage is very close to when mine started having issues (around 125000 KM). The 460 Euro quote is fair considering they are replacing both sensors. You will save money in the long run by doing both at once. Plus, the symptoms you describe, poor engine response and high fuel consumption, should resolve completely once the engine synchronization is restored with new sensors. Would be interested to hear how it turns out after the repair. Keep track of the fuel consumption before and after, you should see a noticeable improvement once the engine timing is properly synchronized again.

Thanks everyone for the helpful feedback! Quick update on my 2015 Q3 situation: Had both sensors replaced yesterday and the improvement is remarkable. The engine synchronization is now perfect according to diagnostic readings. Fuel consumption has already dropped noticeably on my commute today. Final repair breakdown: New crankshaft sensor, New camshaft sensor, Labor and diagnostic time Total came to 460 Euro exactly as quoted Really glad I went ahead with replacing both sensors at once. The misfire symptoms are completely gone, check engine light is off, and acceleration is smooth again. Engine feels like new. Big thanks for confirming this was the right approach. Will track fuel consumption over the next few weeks but already seeing positive results. Definitely recommend anyone with similar symptoms to check their engine synchronization sensors first before looking at more complex issues.