A5 IAT Sensor Issues Causing Multiple Engine Problems

I had a very similar issue with my A4 2.0T from 2019. Having some experience with intake air sensor problems, I can share what worked in my case. The symptoms matched exactly, rough idle, decreased power, and the check engine light. After connecting a diagnostic tool, it also pointed to the IAT sensor readings being off. The repair shop confirmed the intake air temperature sensor was failing intermittently. The fix involved replacing the IAT sensor and cleaning the surrounding intake area. Total cost was 155 Euro including parts and labor. Since the replacement, the engine has been running smoothly with no more warning lights. Before jumping to conclusions though, could you share: Current mileage on your A5, When did these symptoms first appear, Any recent maintenance work done, Are there any other warning lights besides check engine, Does the problem get worse in specific weather conditions This information would help determine if your case is similar and whether the air sensor is truly the root cause.

Last service was done at 35000 KM three months ago, so I have added about 2600 KM since then. Thanks for the detailed information about your sensor replacement. The symptoms started appearing gradually over the past two weeks. I noticed the car temperature readings were inconsistent before the check engine light came on. The engine runs especially rough during cold starts. A basic car diagnostics scan showed P0112 and P0113 codes. No other warning lights are active. The temperature sensor readings seem to fluctuate wildly according to the scan data. Given the codes and symptoms, I am leaning toward replacing the IAT sensor, but wanted to confirm with others before proceeding.

Based on your mileage and the error codes you mentioned, this definitely sounds like the same IAT sensor issue I dealt with. The P0112/P0113 combination typically indicates an intake air temperature sensor that is failing, showing both low and high circuit issues. The fluctuating readings you described match my experience exactly. At 37600 KM, your car is right in the range where these sensors can start acting up. The fact that you notice it more during cold starts further supports the diagnosis. In my case, the temperature readings were also all over the place before the final failure. After replacing my IAT sensor, all these symptoms cleared up: Fluctuating temperature readings stopped, Engine ran smoothly, especially during cold starts, Check engine light turned off, Power returned to normal, Error codes did not return Just ensure the repair shop performs a proper car diagnostics scan after replacement to verify the fix. Having them clean the intake air system while they are in there is also worthwhile preventive maintenance. Since your symptoms and error codes are identical to what I experienced, I am even more confident now that replacing the sensor will resolve your issues.

Thanks for the feedback. After reviewing the diagnostic codes and comparing my situation with similar cases, I feel confident moving forward with the IAT sensor replacement. The matching symptoms, especially the inconsistent temperature readings and cold start issues, make a strong case for the air sensor being the problem. I will schedule the repair this week and have them perform a complete car diagnostics scan afterward to confirm everything is resolved. The 155 Euro repair cost seems reasonable given the symptoms and potential damage from leaving it unfixed. Will update once the temperature sensor is replaced to confirm if this solved the rough idle and power issues. Really helpful to hear from others who dealt with the same problem, made the diagnostic process much clearer.