130 tdi over boosting

[shoolhouse]

Hi all my wife's passat 2002 130 tdi is over boosting and going into limp mode, i read the codes can't remember the code i think it was p1557?.
I've checked the N75 valve,and all vac pipe and cleaned the pressure sensor(the one in the air inlet pipe).
It's looking like the turbo is clogged,may thake it apart and check/clean.
Anyone know were the best place(or just a recommendation) is to get a replacement turbo,just in case it's needed.

[scotty33]

Hi

P1557 is a generic obd code equivalent to vcds 17965, as you say overboost. Also as you already know commonly caused by soot making the vanes 'stick'. In my case it was caused by a faulty 'thrust sensor' (map sensor) though this is said to be a lot less likely. If you can lay your hands on a known good one, maybe worth swapping over, to rule it out.
I would say, before you commit to cleaning the turbo, check the vanes are 'sticking'. There are 2 m6 nuts or bolts securing the vnt actuator to it's bracket, (in between the turbo hotside and coldside) if you unbolt the actuator from its bracket, you should be able to pull the linkage, which should move very freely (almost like there is nothing attached).
It would be possible to seperate the linkage without unbolting the vacuum actuator. The linkage length is factory set and critical because it determines the boost characteristics of the turbo. It really should not be interfered with.

If you have not seen it, a good guide on tdi club:

VNT Repair Procedure - TDIClub Forums

maybe turbo technics or midland turbos would have something?

[shoolhouse]

Cool thanks for your help, i well check the linkage next,and will check out the link( TDIClub Forums) later on tonight.