VW Polo Whistling: Faulty Charge Air Temp Sensor Fix

Had the exact same symptoms on my VW Golf TDI 2015. The whistling noise during acceleration combined with reduced power turned out to be related to the charge sensor and air intake system connection. The root cause was a damaged wiring harness where the charge air temperature sensor connects to the main loom. The sensor itself tested fine, but the connection was intermittent due to corroded pins and a cracked connector housing. The engine management system was getting incorrect temperature readings, causing the power reduction mode to activate. This fault is common across the VAG diesel range. While replacing just the sensor might seem like a quick fix, checking the entire air intake system is crucial. In my case, the faulty connection was allowing unmetered air to enter, throwing off the airflow sensor readings as well. The repair required a new wiring connector, cleaning of the air intake tract, and recalibration of the engine sensors. This was not a serious mechanical issue, but leaving it unfixed can lead to increased fuel consumption and potential turbocharger stress. A proper diagnosis should include testing the charge sensor electrical circuit and inspecting the air intake system for any leaks or damage. Many shops miss these connection issues and jump straight to replacing parts.

Thanks for sharing your experience. It really helps since I have similar symptoms with my 2013 Polo. My temperature gauge also started acting weird before the power loss kicked in. The local shop initially just wanted to replace the airflow sensor without proper diagnostics. After your post, I will definitely insist on checking the wiring and connectors first. The whistling sound matches exactly what Im experiencing. Can you remember roughly how much you paid for the complete fix? Also, has everything been running smoothly since the repair, or have you noticed any other engine sensor issues?

I took my Golf to a different mechanic who actually checked the wiring first, exactly what was needed. The total repair cost was 95€ which covered fixing the cable connection to the charge air temperature sensor. Much cheaper than blindly replacing parts. Everything has been running perfectly since the fix. No more whistling noises, full power restored, and the temperature readings are now stable. The engine management system is getting accurate data from all automotive sensors, and fuel economy has improved back to normal. The key was finding a shop that properly diagnosed the electrical connection rather than just throwing parts at the problem. The airflow sensor and other components in the air intake system were actually fine, it was just that damaged wiring causing havoc with the sensor readings. A proper inspection of the wiring and connections should always be the first step with these temperature sensor faults. Its a common issue that often gets misdiagnosed, leading to unnecessary parts replacement and higher costs.

Had my Polo checked today after getting great advice here. The mechanic I found actually took time examining the wiring connections to the charge air temperature sensor before suggesting any parts replacement. Turns out the connection to the sensor was corroded and loose, causing those weird temperature readings and power issues. The wiring harness needed minor repair and the connector was replaced. Total cost was 120€, way less than the 400€ the previous shop quoted for replacing the entire airflow sensor unit. The whistling noise is completely gone now and power has returned to normal. The engine sensor readings are stable and the check engine light has cleared. Really glad I didnt rush into replacing parts unnecessarily. This whole experience taught me to be more selective with repair shops and insist on proper diagnostics of the electrical systems first. Thanks to everyone who pointed me in the right direction. Having a knowledgeable mechanic check the wiring first saved me both time and money.