Passat tdi turbo cutting in & out . . ?

andy t

have a 130bhp tdi passat & the turbo has started cutting in & out...

might start that car & have no turbo then it might work for a few miles , then stop again...
it doesnt work most of the time

there is no smoke so i suspect a sensor



anyone ever have this issue ???

Chimaera

It sounds like it's going into limp mode. Could be a few things:

Rotten vacuum lines
Failed N75 valve
Stuck vanes on the turbo
Failed MAP sensor
Failed VNT actuator on the turbo

Replacing the vacuum lines is a cheap fix and probably worth doing anyway if they haven't been done already.

After that you need to run diagnostics to see where the problem lies. You're going to have codes for overboost if it's going into limp mode but that won't tell you why it's overboosting. Whoever does the diagnostics for you needs to know how to test for failures in the different parts of the boost control system.

andy t

il start with the vacuum lines & then work towards sensors

where is the n75 valve ?
is that the 1 in the front down near the turbo ? ive heard they give a lot of bother

andy t

i swapped over a map sensor with another one last night & turbo worked so going to get a new one & hope the problem is solved

andy t

map sensor worked a treat,,,
worth a try for anyone else as its a very cheap part