I have an a4 B6 1.8t , having major problems with the turbo. About 3 months ago I took it to the Audi dealer because it was not boosting , it turned out that the boost cutoff valve and the n75 valves were bad , I told them to replace them . Car was running good until the check engine light turned on the code was that it was running too lean , after struggling to find out y it was running lean , I found that 1 of the nipples on the n249 was broken and the dv valve was not hooked up to vacuum. I went out to the dealer and purchased the valve and plugged everything where is supposed to be following the vacuum diagram from a service manual and the car will not boost . As soon as I unhook the dv vacuum line it starts to boost again . Any suggestion I would highly appreciate . Thanks I'm running out of options please help.

 

Hi. I don't know much about your problem. But I felt I needed to at least offer a little advice and let you know that people are reading posts on here.
try posting in the A4 section on here. There are LOTS of people on here with A4 T's who should be able to help you.
Good luck.