VW Sharan TDI Power Loss, Common Causes & Fixes

Similar issues occurred with my VW Touran 1.9 TDI from 2002. I have some experience working with diesel engines, though mainly basic maintenance. The symptoms match exactly what happened after I had my car chip tuned by a small local shop. The car computer started showing dashboard lights and the engine lost significant power. The vehicle diagnostics revealed multiple fault codes related to boost pressure and fuel delivery. I took it to an authorized VW workshop where they discovered the third-party chip tuning was causing conflicts with the engine management system. They had to reset the engine control unit back to factory settings and perform a complete diagnostic scan to ensure no damage was done to other components. The total repair cost was 180€. Before suggesting more specific solutions, could you provide: Current mileage, Whether any recent modifications were done, If the engine issue started suddenly or gradually, What fuel consumption changes youve noticed, If there are any unusual engine sounds These details would help identify if your diagnostic codes might be related to similar chip tuning issues or point to different engine problems.

Last service was done at 38000km and the car has started having this issue right after. Like you, I also noticed the check engine dashboard light, but my vehicle hasnt been modified at all. After using a scan tool to read the diagnostic codes, the mechanic mentioned something about the turbo system, but didnt provide details. The power loss happened quite suddenly during highway driving. Fuel consumption increased by about 2L/100km since the problem started. There is a slight whistling noise during acceleration that wasnt there before. The car feels especially weak when climbing hills. Based on the symptoms, I suspect its turbo-related, but hoping someone can confirm if this matches their experience before I commit to potentially expensive repairs.

Thanks for providing those additional details. The symptoms you describe match exactly what I experienced with my VW before the repairs, especially that whistling noise during acceleration and the increased fuel consumption. Since your car is stock without modifications like mine was, and considering the timing right after service, I suspect the issue could be a boost leak in the turbo system. When my car was diagnosed, the car computer showed fault codes related to boost pressure, which explained the power loss and whistling sound. The actual problem turned out to be a cracked intercooler pipe that developed a small leak. The check engine light came on because the engine management system detected irregular boost readings. The whistling sound was boost pressure escaping through the crack. The repair involved: Full diagnostic scan to confirm fault codes, Pressure testing the entire intake system, Replacing the faulty intercooler pipe, Clearing the engine fault codes Total cost was around 320€ including parts and labor. The car returned to full power immediately after the repair and fuel consumption went back to normal. Worth getting this checked soon since running with boost leaks can cause additional engine stress. Have them specifically check the intercooler and associated piping since those are common failure points after service work.

Based on those detailed responses, let me share my current situation. After hearing about similar turbo-related issues, I took the car back to have the diagnostic codes checked more thoroughly. The car computer showed multiple boost pressure related faults. The mechanic confirmed a whistling noise from the engine bay during a test drive and recommended a complete inspection of the turbo system. They quoted 350€ for diagnostic work including pressure testing and visual inspection of all boost-related components. While this seems a bit high compared to the repair costs mentioned, at least I now have a better idea what to expect. The symptoms match perfectly with the intercooler pipe issue described, especially the sudden power loss, increased fuel consumption, and that distinct whistling during acceleration. It makes sense this could have been disturbed during the recent service. I will proceed with the inspection and post an update once the actual problem is confirmed. The check engine light and engine issue symptoms are concerning enough to justify having it looked at properly rather than risk additional damage. Thanks for sharing those repair experiences. Having this information helps a lot when discussing the problem with the workshop.