Audi A3 Power Loss Due to Temp Sensor Failure

I had a very similar issue with my 2002 Audi A4 2.0L gas engine last winter. With moderate experience working on cars, I initially tried using a diagnostic tool to confirm the error codes, which indeed pointed to a faulty air temperature sensor. The symptoms matched exactly what youre describing, reduced power, rough idle when cold, and the check engine light. The car sensor was giving incorrect temperature readings, causing the engine management system to use wrong fuel mixture calculations. My local workshop confirmed the intake air temperature sensor was defective. The repair was straightforward and cost me 155 Euro including parts and labor. Since the fix, all engine issues cleared up completely. Before jumping to conclusions though, could you share: What specific error codes are you getting? Does the engine performance improve once warmed up? Have you noticed any unusual sounds or vibrations? When was your last routine maintenance done? This information would help determine if your case is similar or if there might be additional underlying problems that need addressing.

Thanks for the replies. My mileage is 114455KM and last service was 2 months ago. The error code was P0113 which points directly to the air temperature sensor. Engine does run smoother after warming up but still feels underpowered. No unusual sounds, just the rough idle when cold. The diagnostic tool readings show the sensor is giving inconsistent temperature values. Last maintenance included new spark plugs and oil change, everything else checked out fine. Sounds like replacing the temperature sensor is the logical next step based on the symptoms and your experience with a similar engine issue.

Thanks for the additional details. Your situation sounds nearly identical to what I experienced with my A4. The P0113 code and inconsistent temperature readings from the sensor are telltale signs. In my case, the faulty air temperature sensor was definitely causing the engine issues and rough cold starts. Just like your vehicle, mine also showed improvement after warm-up, but the reduced power remained noticeable throughout. The incorrect temperature readings were causing the engine management system to miscalculate the air-fuel mixture, particularly during cold starts. Since your maintenance is up to date and you're not experiencing any unusual sounds, I'm even more confident the temperature sensor is your culprit. The repair should resolve the check engine light and restore proper engine performance. One tip from my experience: while changing the air sensor, it's worth checking the connector and wiring for any signs of corrosion or damage. This can sometimes cause similar symptoms and might need addressing to prevent future issues. Would definitely recommend getting this fixed soon, as running with incorrect air temperature readings can affect fuel economy and engine performance in the long term.

Thanks everyone for the helpful responses. After getting these insights, I went ahead and had the IAT sensor replaced at a local shop. Total cost was 140 Euro for parts and labor, which seems reasonable based on what others paid. Happy to report the fix worked perfectly. The check engine light is now off, cold starts are smooth, and full engine power is restored. The diagnostic tool confirms the temperature sensor is now giving consistent readings. For anyone else running into similar symptoms, rough cold starts, check engine light, and reduced power, definitely worth checking the intake air temperature sensor early in the diagnostic process. The repair was much simpler and cheaper than I initially feared. Good reminder about checking the wiring too, my mechanic confirmed the connections were clean but mentioned it's a common related issue to watch for with temperature sensor problems.