SQ5 Power Loss: Faulty Air Temp Sensor Alert

As someone with some automotive repair experience, I had a very similar issue with my 2015 S4. The symptoms matched exactly what you describe, the check engine light, power loss and rough idle. The air temperature sensor was indeed the culprit. My IAT sensor was giving incorrect temperature readings, causing the engine management system to miscalculate the air-fuel mixture. The workshop diagnosed it quickly with proper diagnostic tools. Total repair cost was 155 Euro, including the new temperature sensor and labor. The repair process was straightforward, they replaced the faulty air sensor and cleared the error codes. After replacement, all symptoms disappeared immediately and the engine ran smoothly again. To help provide more specific guidance: Which error codes is your diagnostic showing? Have you noticed if the problems get worse in specific weather conditions? Is the power loss constant or does it come and go? Has there been any recent work done on the intake system? These details would help confirm if your temperature sensor issue matches what I experienced with my vehicle.

Thanks for your helpful reply. After my last service at 182025 KM, I got the following error codes: P0113 and P0072. The power loss is pretty constant and definitely more noticeable in cold weather. The temperature reading seems way off, showing -40C even on warm days. No recent work has been done on the intake system. Based on your experience, this really sounds like the IAT sensor is the culprit. Good to know the repair was straightforward in your case. Will schedule a workshop visit to get this sorted.

Thanks for providing those error codes. Those are exactly what I saw on my S4, P0113 and P0072 specifically indicate a malfunction in the intake air temperature sensor circuit. The -40C reading you mentioned is a classic sign of a failed temperature sensor, identical to what I experienced. The cold weather correlation makes perfect sense too. When my car temperature sensor failed, the engine management system was getting completely wrong air temperature readings, making the cold-weather performance even worse since it couldnt properly adjust the fuel mixture. In my case, replacing the air sensor completely resolved the constant power loss and error codes. The repair itself took less than an hour. The engine issues cleared up instantly after the new sensor was installed and calibrated. Just for your peace of mind, those error codes combined with the incorrect temperature readings and constant power loss mirror my situation exactly. The repair should be similarly straightforward and cost-effective. Make sure the workshop checks the wiring harness connected to the sensor too, though in my case it was just the sensor itself that needed replacement.

The codes, symptoms, and temperature readings pretty much confirm what I suspected about the intake air temperature sensor. Really appreciate you sharing your experience, its helpful to know the repair was quick and relatively inexpensive in your case. The matching error codes P0113 and P0072, plus the fact that my temperature sensor is showing -40C readings, make me confident this is the same issue you faced. Its good to know the power loss problems cleared up immediately after the sensor replacement. Ive scheduled the workshop visit for next week. They quoted around 180 Euro for parts and labor, which seems reasonable based on your experience. Will make sure they check the wiring harness too, as suggested. Looking forward to getting these engine issues resolved and having the car running properly again. Thanks for the detailed insights about your repair experience, its been really helpful in understanding what to expect.