Turbo ok but sometimes Limps

Wrrrr

Member
Joined
Apr 24, 2024
Location
Boston
TDI
2006 Golf 1.9L
My Canadian 2006 golf 1.9 l TDI has 406,000 km about a quarter million miles. I've maintained this car for the last hundred thousand kilometers since I bought it in 2021. I replaced the cold air turbo pipe due to a worn out clip. Most recently I have installed a timing belt water pump as well as a new serpentine belt, alternator, tensioner. In the city the turbo works fine and is consistent up to 60 miles an hour, zippy with no issues. I can accelerate on the highway to 80-85 miles an hour without the turbo. The issue I'm having is that if I'm on an uphill grade moving along around 70 mph if I hit the pedal to call for the turbo it kicks in and then goes into limp mode and while the turbo is engaged the acceleration is negligible and the car maintains as well as it can but as I go uphill the speed continuously decreases. Once I reset the throttle everything is back to (semi) normal. As I drive the car for a couple of weeks eventually the engine light goes back off. This overboost condition PO2034 but when the light is off obviously there is no condition. I don't have a real problem driving the car this way and know how to keep it from doing this but just wondering if this is specifically a turbo issue without evidence of other fault codes it's a bit of a head scratcher. Any suggestions or relevant experiences would be really appreciated.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
Your actuator is probably on its last legs. And acceleration from highway speeds creates a condition where it overboosts and the ECU sends it into limp mode. Unfortunately, actuators are not available for the KP39 that came on a BEW. A new turbo is the best option.
 

Rx7145

Veteran Member
Joined
May 21, 2017
Location
Ohio
TDI
2006 Jetta BRM
You could try the zip tie mod the turbo stop is probably adjusted wrong.
 

Wrrrr

Member
Joined
Apr 24, 2024
Location
Boston
TDI
2006 Golf 1.9L
Your actuator is probably on its last legs. And acceleration from highway speeds creates a condition where it overboosts and the ECU sends it into limp mode. Unfortunately, actuators are not available for the KP39 that came on a BEW. A new turbo is the best option.
I'm a noob. It's unclear to me how well the car drives currently with the turbo being responsive up to 70mph ish, then that you mention it may be that it's on it's last legs. Are you saying if the KP39 actuator (fails completly) I'll be dead in the water? I've been assessing this condition for a year and the car seems fine (driven as I've noted).
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
The actuator will continue to slowly deteriorate. Ultimately you'll end up with limp mode all the time. The turbo itself is probably fine, only the actuator is failing. At this point it sounds like you can continue to drive it for a while.
 

Rx7145

Veteran Member
Joined
May 21, 2017
Location
Ohio
TDI
2006 Jetta BRM
.... almost six years later? :p
Your actuator is probably on its last legs. And acceleration from highway speeds creates a condition where it overboosts and the ECU sends it into limp mode. Unfortunately, actuators are not available for the KP39 that came on a BEW. A new turbo is the best option.
I think being an 06, it would be a BRM engine code. Amazon does show an actuator available for it. I don’t know if it would work. Looks like it should.
 

Wrrrr

Member
Joined
Apr 24, 2024
Location
Boston
TDI
2006 Golf 1.9L
I used to mechanic on my 76' F-100 Straight 6. Climb right in and work on it. No more.... no lift/hoist or real skills for my BEW mk4 Golf. I have a really good shop I go to in Canada but seriously, the VNT-17 looks like I can get a kerma smart actuator for a $100, but while digging in further, is this the real issue? I could go all in and get a new turbo, but what if it isn't the actuator and (again) reading in here there is talk about the egr and many other things to check, which, for anyone is obviously time consuming. If you read my original post, the turbo works good up to 70mph and I hear that may mean the actuator is on it's way out or going to fail. The only code is overboost PO2034 and the light will go off a week or so after reset. I appreciate all the replies !!
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
There is no factory "smart" actuator for the KP 39 turbo. Having said that you can get an aftermarket chinese copy, normally I don't suggest you buy chinese anything for your car but I have purchased this about 2 years ago and it's still working fine.


You will have to set it up properly with a handheld mity vac. You can also change it from underneath the car without removing the turbo.

However before buying anything you can check the actuator with that hand held mity vac. The actuator should hold vacuum when applied. Also check the 3 wire plug-in that makes this actuator a "smart actuator" those 3 wires are very thin and prone to damage.
 

Wrrrr

Member
Joined
Apr 24, 2024
Location
Boston
TDI
2006 Golf 1.9L
There is no factory "smart" actuator for the KP 39 turbo. Having said that you can get an aftermarket chinese copy, normally I don't suggest you buy chinese anything for your car but I have purchased this about 2 years ago and it's still working fine.


You will have to set it up properly with a handheld mity vac. You can also change it from underneath the car without removing the turbo.

However before buying anything you can check the actuator with that hand held mity vac. The actuator should hold vacuum when applied. Also check the 3 wire plug-in that makes this actuator a "smart actuator" those 3 wires are very thin and prone to damage.
Without knowing much... would that fit my 06' Mk4 Golf 1.9L BEW? I know it says BEW but for 04-05?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I can only imagine the rust issues that would foul up trying to replace the VNT actuator on an 18 year old car from Boston that has covered a quarter million miles.

I'm with IBW, I'd look into a new turbocharger.
 

Wrrrr

Member
Joined
Apr 24, 2024
Location
Boston
TDI
2006 Golf 1.9L
I can only imagine the rust issues that would foul up trying to replace the VNT actuator on an 18 year old car from Boston that has covered a quarter million miles.

I'm with IBW, I'd look into a new turbocharger.
LOL. (Canadian built) Actually Canadian miles in northern ontario, not as much salt. Only in Boston for a short stretch. On to NC in the Fall. But I get what you said seriously.
 

sptsailing

Veteran Member
Joined
Jul 9, 2010
Location
Safety Harbor, FL
TDI
2006 Jetta Manual, stock with Panzer Plate & Franko6 modified EGR cooler & CAM
My Canadian 2006 golf 1.9 l TDI has 406,000 km about a quarter million miles. I've maintained this car for the last hundred thousand kilometers since I bought it in 2021. I replaced the cold air turbo pipe due to a worn out clip. Most recently I have installed a timing belt water pump as well as a new serpentine belt, alternator, tensioner. In the city the turbo works fine and is consistent up to 60 miles an hour, zippy with no issues. I can accelerate on the highway to 80-85 miles an hour without the turbo. The issue I'm having is that if I'm on an uphill grade moving along around 70 mph if I hit the pedal to call for the turbo it kicks in and then goes into limp mode and while the turbo is engaged the acceleration is negligible and the car maintains as well as it can but as I go uphill the speed continuously decreases. Once I reset the throttle everything is back to (semi) normal. As I drive the car for a couple of weeks eventually the engine light goes back off. This overboost condition PO2034 but when the light is off obviously there is no condition. I don't have a real problem driving the car this way and know how to keep it from doing this but just wondering if this is specifically a turbo issue without evidence of other fault codes it's a bit of a head scratcher. Any suggestions or relevant experiences would be really appreciated.
I had weird sudden limp mode years ago that was due to vacuum leaks. In my car's specific case, I finally traced it to a leaking vacuum reservoir that would create problems only when I tried to drive at higher elevations. The vacuum pump created enough vacuum to overcome the leak at low elevations only. Perhaps the valve controlling vacuum to the turbo is sticking. Your VCDS should tell you a lot.
 

325_Guy

Veteran Member
Joined
Jun 21, 2011
Location
West Central Texas
TDI
MkV Jetta
Your symptoms track with mine when my actuator popped a hole in the diaphragm. Drove alright around town, but I could consistently trip an overboost by giving full throttle on an uphill grade at the speeds you see as well- 60 to 70mph.

The good thing is this was manageable in-car. The trick is to reduce the need for full boost. I'd hold 4th longer than usual until I hit the top of the hill, or be the slow guy and hold off on acceleration until I was at the top of the hill.

The other good thing is this is easily diagnosable with a mity-vac. Apply vacuum to the actuator nipple. You should see the actuator draw in, and there should be no leaking whatsoever.

....edited out the not relevant parts....oops!....
 
Last edited:

Rx7145

Veteran Member
Joined
May 21, 2017
Location
Ohio
TDI
2006 Jetta BRM
So I guess I have to ask a dumb question. Doesn’t the BRM and the BEW both use a vacuum actuator and couldn’t both of them have a hole?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
Not the same actuator, no. One pulls, one pushes, one's on top, one's on bottom. But they both do work via pulsed vacuum, so yes the both could have a leak internally, resulting in no boost.

Very easy to check with VCDS... especially the BRM, as it's rod is easy to see from the top.
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Without knowing much... would that fit my 06' Mk4 Golf 1.9L BEW? I know it says BEW but for 04-05?

All BEW engines take the same style actuator. Yes it would fit. If you live in the salt belt or have lived there the two bolts that hold that metal flange to the turbo will probably round off when you attempt removal. That would necessitate removal of the turbo to drill those bolts out. Oilhammer and IBW have a point, if you need to remove the turbo you are probably better off replacing it. You can always sell the old one, or keep it as a spare after cleaning it, provided it checks out good.
 

Wrrrr

Member
Joined
Apr 24, 2024
Location
Boston
TDI
2006 Golf 1.9L
Great advice from everyone. I appreciate it. Moving toward the new turbo everyday. I see 5 different models ranging from the most affordable GT1749vb and on up. This seems like a smart choice but what additional information do I need, or suggest a different model? I'm not a performance junkie, this is my daily driver.

Notes from one of the suppliers I found (performance tdi in canada) https://performancetdi.com/shop/vnt17-gt1749vb-turbo-for-alh-bew-1-9-tdi/
The GT1749vb is a 100% bolt-on option for the BEW, but you will need an adapter for the piping on the ALH . It works with the stock downpipe.We strongly recommend to order a braided steel oil feed line and gasket kit for the installation. For the BEW, you will also need to delete the EGR, or fit a special EGR pipe if you want to keep the EGR. It is fully balanced with an actuator that is precisely calibrated – ready to install.
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I don't think the VNT-17 is a great turbo on the BEW unless you have the car tuned. It's laggy otherwise. If you want to keep it stock I'd go with a replacement KP39. If you're willing to have it tuned, the 17 will work great.
 

Tdijarhead

Top Post Dawg
Joined
Nov 10, 2013
Location
Lawrenceville PA
TDI
2003 TDI Jetta Daughters Car, 2001 TDI Beetle, Wife’s car, 2005 Golf TDI Mine, all 5 spds
Just to throw this out there, don’t go to eBay or amazon to buy a turbo. Although idparts, cascadegerman, and metalmanparts all have an eBay store so they would be okay, though I prefer to deal directly with any one of them. Other than those 3 any turbo bought off eBay or amazon is likely to be a chinese copy of something that is guaranteed to fail.
 
Top