VW Transporter Turbo Trouble: Power Loss & Hissing

Having some experience with turbo system issues, I faced almost identical symptoms on my 2021 VW Crafter diesel. The whistling noise and power loss during acceleration were particularly concerning. The intake manifold pressure sensor connection was causing these issues. After noticing the problems, I took it to a workshop where they diagnosed a faulty cable connection to the turbo boost sensor. The repair involved replacing the wiring and connector, costing 95€ including diagnostic time. Key symptoms that matched: Check engine light, Power loss with turbo boost issues, Whistling noise under load, Irregular idle, Increased fuel consumption Before suggesting more specific solutions, could you share: Current mileage, Any previous turbo-related repairs, When the symptoms first appeared, Whether the issues occur more during cold or warm engine, Any error codes from diagnostic scans The air intake and turbocharger system is complex, so getting proper diagnosis is crucial. A complete inspection of the turbo system components, including boost lines and connections, would be advisable.

Thanks for sharing your experience with the Crafter. I have 80243km on my Transporter, with the last service done 2 months ago. The symptoms started appearing gradually over the past 2 weeks. Initially just the whistling noise, then the performance issues followed. The check engine light only came on 3 days ago. The problems seem consistent regardless of engine temperature. I had no previous turbo-related repairs, as the vehicle is relatively new. Unfortunately, I do not have access to diagnostic equipment to check error codes. The boost problems and engine performance issues do seem quite similar to what you described. Based on your feedback, I will have the workshop specifically inspect the boost sensor connections and wiring when I take it in. Hopefully its just a wiring issue like in your case rather than a more serious turbo system problem.

After fixing the boost sensor wiring on my Crafter, I learned these issues can sometimes be more complex. While the initial repair resolved most symptoms, I later discovered a small crack in one of the intercooler hoses that was contributing to the boost pressure problems. The engine light came back on after a few weeks, and the whistling noise returned, though less severe. A thorough inspection revealed the additional issue. The total repair ended up costing 280€ including the hose replacement and labor. For your Transporter, given the gradual onset of symptoms, I would strongly recommend: 1. Full pressure testing of the turbo system 2. Inspection of all boost hoses and connections 3. Testing the turbocharger operation 4. Checking the wastegate function The consistent problems regardless of engine temperature point toward a possible physical leak rather than just a sensor issue. The turbocharger and associated components should still be under warranty at 80000km, so document all symptoms carefully when you visit the workshop. Once fixed, keep monitoring your boost pressure readings if possible, as early detection of issues can prevent more extensive damage to the turbo system.

Based on all this helpful information, I will definitely get my Transporter checked thoroughly. The details about the hidden intercooler hose crack in addition to the boost sensor wiring issue is particularly eye-opening. Since my symptoms developed similarly with the whistling noise first, followed by performance problems, I will request the complete inspection checklist you suggested, focusing on both the electrical and mechanical components of the turbo system. I checked my warranty paperwork and confirmed the turbocharger system is still covered. I have documented all the symptoms with dates and will bring this information to the workshop. I will insist on pressure testing of the entire boost system and thorough inspection of all hoses and connections. I plan to schedule the repair next week. Once fixed, I will look into getting a boost pressure monitoring tool to catch any future turbo system issues early. Thanks for helping me understand the potential complexity of these problems beyond just a faulty boost sensor.