Q3 TDI Boost Sensor Causing Power Loss and Stalling

Had the same symptoms on my Q5 2.0 TDI from 2019. The engine light came on during highway driving, followed by significant power loss and the characteristic whistling noise. The turbo boost issues were caused by a loose connection on the boost pressure sensor, creating a minor boost leak. The fix involved checking the wiring harness where it connects to the pressure sensor. The connector had corroded pins and wasnt making proper contact. A proper cleaning of the connector pins and securing the plug connection resolved the turbocharger issues. The engine light cleared after the repair and the turbo boost returned to normal. This is typically not a serious problem if caught early, but leaving it unattended can lead to the turbocharger running outside its normal parameters. The symptoms you describe, especially the high fuel consumption and power loss, match exactly what happens when the boost pressure sensor cant properly regulate the turbo. Would recommend getting the specific error codes read first. This will confirm if its indeed the pressure sensor connection rather than a mechanical turbocharger issue.

Thanks for sharing your experience with the boost pressure sensor issue. Mine turned out similar, it was also just the connector and wiring causing all those turbocharger problems. The intake manifold and related sensors were actually fine, which was a relief. Do you remember roughly how much the repair cost you? Also curious if youve had any other boost leak issues since getting it fixed? My engine light hasnt come back yet, but always good to know what to watch out for.

Good news about your boost pressure sensor getting sorted! The repair on my Q5 cost 95 Euro to fix the faulty cable connection. The mechanic confirmed it was just the connector causing the turbo boost problems, similar to your case. Since having the defective wiring fixed, my turbocharger has been working perfectly with no check engine lights or boost leak issues. The turbo system is performing as it should, no more power loss, excessive fuel consumption, or strange whistling noises under acceleration. Its been over a year now without any repeated problems. As long as the connections are properly cleaned and secured during repair, these boost pressure sensor issues typically dont come back. Just keep an eye on your boost performance during acceleration and fuel economy, these are usually the first indicators if something starts going wrong again with the turbo system.

Thanks for the helpful advice. Just wanted to close the loop on my turbo troubles. Took it to a new mechanic who actually listened and diagnosed the issue properly. The whole repair took about an hour, they cleaned the boost sensor connections and replaced a damaged wire in the turbo system that was causing the erratic readings. Total cost came to 120 Euro for parts and labor, which felt fair considering how much better the car runs now. The whistling noise is completely gone, fuel economy is back to normal, and the engine pulls strong again. Most importantly, no more check engine light. For anyone facing similar symptoms, definitely get those boost pressure readings checked first before assuming the worst about your turbocharger. A simple wiring issue can mimic major turbo failure symptoms. Really glad I asked here before spending big money on unnecessary repairs.