turbo linkage/actuator doesn't move?

jrr6

Member
Joined
Sep 20, 2006
Location
Suburbs of Boston, MA
TDI
2000 Jetta TDI
I have a 2000 Jetta TDI 5-speed with 105k miles. Recently, it has been losing power (and going into limp mode) when I try to accelerate up a hill at highway speeds. Sometimes CEL comes on; I had the dealer read the code and it was P1556 -- Boost deviation negative, intermittent.
Upon reading some of the articles here, I replaced the MAF, and the dealer replaced the N75... still the same symptoms.
After reading yet more posts here, I bought a Mityvac and hooked it to the turbo actuator, and it looks like the linkage barely moves under vacuum -- maybe 1mm at -20psi. The linkage is at the top position, and it looks like the space down to the stop is about 10mm or more. I can't move the linkage with my finger either.

Some of the threads here say you can work the linkage back and forth to loosen it up... but how hard can you/should you push or pry on the thing to do so? (with the actuator attached; I don't have the tools to take it off) I assume it is really supposed to move through the full range, but if it's stuck in one position why don't I get the CEL constantly?

The other weird thing is that I had the turbo replaced (by the dealer, under warranty) just 30K miles and 2.5 years ago. Could the thing really be stuck up that bad that short a time?

Thanks for any advice.
 

Jetta2001TDI

Veteran Member
Joined
Jan 10, 2008
Location
Florida
TDI
2001 jetta
jrr6 said:
I have a 2000 Jetta TDI 5-speed with 105k miles. Recently, it has been losing power (and going into limp mode) when I try to accelerate up a hill at highway speeds. Sometimes CEL comes on; I had the dealer read the code and it was P1556 -- Boost deviation negative, intermittent.
Upon reading some of the articles here, I replaced the MAF, and the dealer replaced the N75... still the same symptoms.
After reading yet more posts here, I bought a Mityvac and hooked it to the turbo actuator, and it looks like the linkage barely moves under vacuum -- maybe 1mm at -20psi. The linkage is at the top position, and it looks like the space down to the stop is about 10mm or more. I can't move the linkage with my finger either.

Some of the threads here say you can work the linkage back and forth to loosen it up... but how hard can you/should you push or pry on the thing to do so? (with the actuator attached; I don't have the tools to take it off) I assume it is really supposed to move through the full range, but if it's stuck in one position why don't I get the CEL constantly?

The other weird thing is that I had the turbo replaced (by the dealer, under warranty) just 30K miles and 2.5 years ago. Could the thing really be stuck up that bad that short a time?

Thanks for any advice.
You need to isolate what part is gone bad, the actuator or the turbo.
The actuator rod is held with a c-clip to the turbo vane control arm. Disconnect it, and see if you can move the turbo vane control arm. It should move freely with no resistance. If it does not, you have a problem with your turbo and it needs to be cleaned. If the turbo vanes moves fine, then apply vacuum to the actuator while it is disconnected and see if it moves. If it does not, then it is your actuator.
 

jasonTDI

TDI GURU Vendor , w/Business number
Joined
Apr 26, 2001
Location
Oregon, WI
TDI
20' RAM 3500 CCLB dually HO/Aisan. 2019 Cherokee 2.0T
Running with no underpan on will kill it in a heartbeat as well as driving around really slow.
 

jrr6

Member
Joined
Sep 20, 2006
Location
Suburbs of Boston, MA
TDI
2000 Jetta TDI
Hmm... my skid plate is on, but there's a smallish crack/hole in the side skirt. I wonder if that could kill the actuator in only two winters? Is there a way I can test the actuator without taking it off?
Also, if the actuator were stuck, would it still hold vacuum? It holds 20psi steady.
 
Last edited:

jasonTDI

TDI GURU Vendor , w/Business number
Joined
Apr 26, 2001
Location
Oregon, WI
TDI
20' RAM 3500 CCLB dually HO/Aisan. 2019 Cherokee 2.0T
Disconnect the clip from the end where it connects to the turbo arm. Put some lube on it first though. Keep an eye on it as it tends to go flying when it comes loose. If the arm for the VNT moves free the issue is the actuator. If not it's the turbo. It can be worked a few hundred times and sometimes it'll clear up without issue. You need to drive it a lot harder to actuate it.

There is the issue of a possible bad N75 valve too causing it to not articulate completely and thus freezing up.
 

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
I find that a small vice grip can be put on the vnt arm coming out of the turbo, and you can use that to work the mechanism back and forth really easily.

-J
 
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