2 codes, limp mode.

[Slf-951]

So here's how it all plays out. I bought my early 99 mk3 TDi about 2 months ago. Slowly I'm trying to get her good for the road. Not that it was bad... But needs a little attention all over the place.

I've done a good bit to get it road worthy, now I'm down to this. P1550, been getting that one since day one, so I replaced all the vac lines, including the one in the computer... All did look good except the one to the wastegate actuator, so I had high hopes. So I took it out for a ride yesterday, and instead of it being hard to get the code to set, it was easier than before. I got it just pulling through 3rd gear getting on the highway. Before it would take one particular hill, a big one on the highway... About halfway up. And with that I'm getting both p1550(boost deveation) and p1549(boost control valve short to ground) now.

Here's my question, as I suspect the valve to be bad... The car never felt or sounded as if it was over boosting, I suspect that it has been underboosting the whole time. And even when it hits limp mode, it isn't the worst it could be(like my mk4 auto in limp!), can still make it up said hill...
So... Boost pressure on these opens the wastegate, right? The n75 just bleeds boost pressure so the waste gate opens at a higher intake pressure, right? And, if the coil inside of the valve isn't working propperly, I'm guessing it could be giving me the p1549 code...?

So if my idea sounds correct (I hope it's that easy), where is the best place to purchase one(cheapest price for factory?) and have it as fast as possible??

Thanks in advance!!

[Keithuk]

Welcome to the forum.

VAG Error Code: 17958
EOBD II Error Code: P1550

Fault Location:
Turbocharger (TC) pressure - control difference

Possible Cause:
Intake/exhaust leak.
Hoses interchanged/not connected.
Manifold absolute pressure (MAP) sensor (G71).
Turbocharger (TC) wastegate regulating valve.
Turbocharger (TC) wastegate actuator.
Turbocharger (TC).


VAG Error Code: 17957
EOBD II Error Code: P1549

Fault Location:
Turbocharger (TC) wastegate regulating valve - open circuit/short to earth

Possible Cause:
Wiring open circuit/short to earth.
Turbocharger (TC) wastegate regulating valve.

As taken from my Free EOBD II Error Codes software

[lira42069]

having problem with vnt tring to remove with out removing turbo

[Seatman]

Originally Posted by lira42069

having problem with vnt tring to remove with out removing turbo

You can remove the actuator without removing the turbo but not the actual vnt mechanism, that'll need the turbo off.