on the way home yesterday i lost most power,heater plug light came on.i knocked it off and on again.was ok but not as it should be.this happened three times on the way home.

had the vagcom on today came up with upper limit perameters not reached.

we cleared the code and it was a lot better.only for it to go back to how it was within 30 miles.

anyone else come across this fault.

does it look like a turbo.

So I guess the possibilities are:

Defective N75 valve

Vacuum leak between N75 and VNT actuator

Clogged VNT mechanism.

You could try doing an N75 duty cycle test on VCDS and observing the movement of the VNT actuator?

So I guess the possibilities are:

Defective N75 valve

Vacuum leak between N75 and VNT actuator

Clogged VNT mechanism.

You could try doing an N75 duty cycle test on VCDS and observing the movement of the VNT actuator?

thanks.i will let you know how we get on.

Hi Ozzy. Can you post up the exact fault codes? It's not clear why you think it's an underboost based on what you mentioned you saw in VCDS. Also forgot to say if it is lower boost pressure than expected, look for boost leaks.

Hi Ozzy. Can you post up the exact fault codes? It's not clear why you think it's an underboost based on what you mentioned you saw in VCDS. Also forgot to say if it is lower boost pressure than expected, look for boost leaks.

should get it tomorrow.

it read something like-upper boost limt not achieved