A5 2.0T FSI Boost Issue with Temperature Sensor Fault

The charge sensor fault you describe matches what happened with my A4 2.0T FSI (2012). The whistling sound during acceleration coupled with reduced power are typical symptoms of a faulty charge air temperature sensor connection. In my case, the issue was a loose wiring harness connection to the temperature sensor. The vibrations from driving had gradually worked the plug loose, causing intermittent connection issues. The engine would detect these fluctuations and reduce power as a protective measure. The fix required: Cleaning the connector pins, Replacing damaged wire insulation, Securing the harness with new clips, Testing the temperature sensor readings While this was not a serious repair, leaving it unfixed can lead to: Continued power loss, Poor fuel economy, Potential damage to other engine sensors, Inaccurate air-fuel mixture A proper diagnosis should include checking both the sensor itself and its connection integrity. Often the temperature sensor works fine, but the wiring or plug connection is the root cause. Make sure the shop performs a complete circuit test rather than just replacing parts.

Thanks for sharing your experience with the air temperature sensor issue. Your symptoms sound identical to what I faced. My Audi A5 was giving me similar grief last summer, reduced power, that same whistling noise, and the dreaded check engine light. Glad to hear it was just a wiring issue in your case. The automotive sensor diagnosis in my situation revealed a completely failed charge air temperature sensor that needed replacement, along with some damaged wiring. Just curious, do you remember roughly what the repair ended up costing you? And has everything been running smoothly since the fix? I had a few small issues crop up afterward with the engine sensor system that needed attention, so wondering if you experienced anything similar.

After getting my A4 checked by a mechanic last week, I can confirm the charge air temperature sensor error was fully resolved. The fix was straightforward, just a faulty cable connection to the sensor that needed repair. Total cost came to 95 Euro for the wiring work, which was much better than replacing the entire airflow sensor unit. The car has been running perfectly since the repair, no more power loss or whistling sounds. The temperature gauge readings are now stable and accurate. Unlike your experience, I havent had any follow-up issues with the engine sensor system. The early diagnosis probably prevented additional complications with the air intake system. Make sure your mechanic thoroughly tests the temperature sensor connection even after repairs. A proper fix should include checking the entire circuit, not just the obvious components. This helps avoid those secondary problems you mentioned experiencing.

I took my A5 to a new mechanic yesterday after reading the responses here. The complete diagnosis revealed a failed charge air temperature sensor plus some corroded wiring, exactly what I was worried about. The total repair came to 280 Euro which included: New temperature sensor, Wiring harness repair, Labor costs, Full system testing The mechanic did a thorough job testing the entire air intake system and airflow sensor connections. After the fix, the engine performance returned to normal with no more whistling sounds. The temperature gauge now shows consistent readings during acceleration. This was definitely a better experience than my previous mechanic who just wanted to replace parts without proper diagnosis. Really glad I got a second opinion and proper repairs done. The car runs perfectly now, no power issues or warning lights.