[ainarssems]

It could be sticking VNT mechanism on turbo, incorrectly adjusted VNT rod length or a problem with regulating system electrical or vacuum whichever you have on your car. It could be that VNT was all the time in one end position trying to increase boost when you had leaking hose and did not get exercised so now it is not moving freely to other end position. You cannot service it without taking turbo apart. Only thing you can do is go into basic setting on VCDS with car in idle, this will move VNT actuator from one end position to other. You should see pressure changing from 980mbar to 1080mbar or thereabouts as it moves. You can also observe actuator as it moves and check if it does travel full length and possibly help a bit if doesn't. Hopefully it will work OK once you get it moving. It should learn parameters while in basic mode as well.


Our A6 was overboosting as well and it had turbo replaced by previous owner. Not overboosting enough to get fault code but you could see it in logs. It is possible that old turbo died a premature death because of overboosting or it could be that it was fine before and new turbo's actuator was not adjusted perfectly. Anyway doing mapping I adjusted VNT control map to minimize overboost.