B5.5 MY05 2.0 TDi P0299, P0101

VariantB3_VR6

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05 B5-A, 01 A4-M
Working on a friend's Passat wagon, and he wants me to replace the turbo to fix the code. It 'may' be the turbo, but I want to make sure before throwing useless parts at it..
I've read on here many times that it could be the turbo, a boost leak, the MAF, the EGR, N75, the wastegate, etc. I've vacuum and boost-tested the wastegate, and it seems fine, moves freely, and will hold boost/vacuum.
The car has 393K on it and I'm unsure of the previous history, other than it was a one-owner before he bought it a couple years ago. It's been sitting now for almost a year, as it was going in to limp mode constantly.
I ran VCDS and pulled the P0299 and P0101. I saved the file, cleared the codes, but can't get them to reappear, as he stated was pretty easy to get the codes to come back; I just can't duplicate it just yet..

Having not a ton of VW diesel knowledge (I work on Cummins diesels) and their quirkiness, what's a good avenue to go down, before we start throwing a bunch of unneeded parts at it?
Thanks in advance, guys!
 

MOGolf

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Check the vacuum lines from the vacuum pump all the way to the N75 (inconveniently low at the front of the engine) and from N75 to the actuator. Look closely at the connections to the N75. You'll need an inspection mirror. One or more may be splitting at the ends attaching to the N75 nipples.

When you tested the actuator and it held vacuum, did it move to the stop and return freely when vacuum was released?

It doesn't have a wastegate. It's a variable vane turbo.
 

VariantB3_VR6

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05 B5-A, 01 A4-M
Check the vacuum lines from the vacuum pump all the way to the N75 (inconveniently low at the front of the engine) and from N75 to the actuator. Look closely at the connections to the N75. You'll need an inspection mirror. One or more may be splitting at the ends attaching to the N75 nipples.
Will do!
When you tested the actuator and it held vacuum, did it move to the stop and return freely when vacuum was released?
It did move smoothly. Even if I move it with my fingers, it feels unobstructed.
It doesn't have a wastegate. It's a variable vane turbo.
True, thanks for pointing that out. I knew it was VNT, just was also working on my CC 2.0TSi (yes, it's also broken) and had 'wastegate' on the brain.
 

oilhammer

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There are just too many to list....
Sounds like a boost leak to me. There are four rubber charge air hoses between the turbocharger and the intake... and I have only ever seen two split open. The S-shaped one out of the turbo to the crossover pipe, and the little L-shaped one back by the firewall into the intake throttle flap. Doesn't take much, look for oil stains spit out that is the tell-tale sign of a small hole.
 

VariantB3_VR6

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Sounds like a boost leak to me. There are four rubber charge air hoses between the turbocharger and the intake... and I have only ever seen two split open. The S-shaped one out of the turbo to the crossover pipe, and the little L-shaped one back by the firewall into the intake throttle flap. Doesn't take much, look for oil stains spit out that is the tell-tale sign of a small hole.
I went to remove the one from the throttle flapper. As I reached under the pipe to feel for the clip release, and my fingers were covered in wet oil..
I pulled it off, and there were no holes in the L-hose. So I'm guessing the o-ring. Looks like all the o-rings (7) runs about 80$.
 

oilhammer

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There are just too many to list....
It would be rare that the o-rings alone would cause a low boost DTC, unless one was physically completely blown out. I'd check that S-hose down low.

And of course also check for crash damage down low, lots of intercoolers get damaged from crashing into curbs.
 

VariantB3_VR6

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Will do. what would I look for on the S hose, anything in particular? I was unsure about the o-rings, I'm just grasping at straws, here, since nothing it really standing out to me for the codes, which is why I was thinking about replacing them. There's no noticable end-play or thrust play in the turbo, even with 393k miles on it.

Also, to mention (might not be related).. there's a vacuum pump (?) on the back of the head, with a large line that goes to the firewall into a rubber fitting. This does NOT fit snug; hell, it barely stays in the rubber at the firewall..

Also the IC hoses are pretty oiled up inside. Is this usually due to a breather needing replaced on the cam cover?
 

Tom in PT

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Look for chafing of the S hose against a wire (ground?) down low, there are some posts and a few pictures on that here, do a search.
 

VariantB3_VR6

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05 B5-A, 01 A4-M
So, the S-hose has a fat 2" long split! (thanks @oilhammer ). Additionally, the lower part of the S-hose didn't look fully seated into the cross-over tube. I am going ahead and replacing all the 3 & 5mm vacuum lines, as well as the N75.
The big vacuum line (from pump to firewall) fits really sloppy in the firewall grommet. Is there a 'work-around' to tighten this fitting?
 

VariantB3_VR6

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05 B5-A, 01 A4-M
3B0145828K
is the number I found, but not sure it's what I need. For 2005 GLS 2.0L TDi BHW Passat FWD-AT, 400k mi. Everything I find for this PN says 1.9L and November delivery, and $300!!... o_O That's more than the car's worth lol
 
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auntulna

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05 GLS Passat wagon, mit panzer plate
If it makes you feel better, it cost $300 10 years ago, so no inflation!! Until you get a new replacement, you might try Gorilla tape with a couple clamps around it. My 90 degree hose split once and we got home OK over 500 miles that way.
 

Scubanero

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There are cheaper versions available and I have tried a couple. The $20 ones from China don't last very long. I have had decent (couple years and still good) performance from one from europe for about $60. Look for one with plastic end pieces.
 

MOGolf

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FCPeuro.com is $206. It is Vaico brand from Turkey and is found at several aftermarket parts suppliers.
 

VariantB3_VR6

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FCPeuro.com is $206. It is Vaico brand from Turkey and is found at several aftermarket parts suppliers.
I ended up with a Vaico from ECS for about $200. Also replaced the N75, and all the vac lines. Did all that today, as well as replace the stupid clip on the turbo outlet-to-S hose.. Got the clip from Jim Ellis VW. Put it all together, replaced the fuel filter, as well.
Drove it around for about 20 minutes, no issues. Ran down the interstate for about 5 miles, no issues.. Crossed under to get back on the interstate and head home, turned onto the on-ramp, and Emissions! light popped on.. Cycled ignition to clear LIMP mode, about 1/2 way up the ram, it popped up again and went back to limp mode. I eased it home, VCDS showed P0299 again. 2130 requested, 1700-ish actual..
Unless the turbo has taken a ****, I don't know what the problem is.
I'm open to suggestions, for sure.. I'm kinda guessing/leaning to a turbo failure? I mean, AFAIK, it's OEM with 393k miles on it.
 

Scubanero

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It sounds like something didn't stay put. Sometimes you have to adjust the lugs (with a file) on the hose connectors so that the clip engages properly. I have had an O ring blow out as well.
 

MOGolf

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And if not that, it might be that you have another hose split, another connection location that leaks, a vacuum line issue at the N75 or the nearby vacuum ball, or a faulty sensor. Re-checking the S-hose replacement is the first thing to do. Be sure to push the hose into the turbo and cross-over pipe as far as possible, and the clips in their slots on both sides.

BTW, did you reposition the ground wire away from the S hose if it hadn't been done previously? Just loosen the nut move the cable so it doesn't contact the hose, and retighten the nut. It would not have rubbed a hole in the new hose that quickly. I'm just asking to make sure it doesn't happen.
 

VariantB3_VR6

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It sounds like something didn't stay put. Sometimes you have to adjust the lugs (with a file) on the hose connectors so that the clip engages properly. I have had an O ring blow out as well.
I verified ALL my connections for charge-air. All o-rings looked perfect, all snap-connections were solid. The ground wire wasn't touching the S-hose, so no issue there; the original one just split (I'll snag a pic tomorrow to show where it split).

All the clips are fully seated.

And if not that, it might be that you have another hose split, another connection location that leaks, a vacuum line issue at the N75 or the nearby vacuum ball, or a faulty sensor. Re-checking the S-hose replacement is the first thing to do. Be sure to push the hose into the turbo and cross-over pipe as far as possible, and the clips in their slots on both sides.

BTW, did you reposition the ground wire away from the S hose if it hadn't been done previously? Just loosen the nut move the cable so it doesn't contact the hose, and retighten the nut. It would not have rubbed a hole in the new hose that quickly. I'm just asking to make sure it doesn't happen.
Another Hose is a possibility. I'll go over the vacuum lines again in the morning. I'm truly baffled. I wished I had a smoke tester LOL I have a pressure tester, so I might try and pressure-test from the hose at the MAF, toward the turbo (removing the MAF from the circuit, I mean.)

Thanks for your brain-storming, guys.. it indeed helps..
 

VariantB3_VR6

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I tried a boost leak test.. I could get zero pressure to build in the intercooler system. like I turned it up to 20-25psi, and the rubber boost hoses never even got tight to squeeze..
What Im I doing wrong? lol I pulled the hose from MAS/MAF sensor, inserted my air fitting to that hose (to turbo inlet), tightened it down, and worked from 5psi, up to 25psi, and never gained pressure, nor did I ever hear a leak.. It must be escaping through somewhere...
 

Scubanero

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I had to block the charge air system at the turbo inlet and at the L hose outlet to get any result. I also had to keep the air supply on and use my hands to find the leak because the leak didn't make any noise. It never held pressure even after repairs. Probably O rings, but I think a small leak is no consequence.
 

Scubanero

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Once was a split in the L hose. Another was a missing O ring at the bottom of the S hose - blown out I presume. The hole in the S hose from the ground wire didn't need a pressure test.
 

VariantB3_VR6

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Cool.. I'm gonna have to get a cap to cap off the L-hose tomorrow, as I can't build any pressure to do a smoke test. I built a tester today, but it was useless without pressure lol
 

VariantB3_VR6

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So capped off the IC plumbing between the 90* and the turbo inlet.. 8psi + smoke test showed no leaks.. VGT actuator sweeps up and down smoothly under vacuum, starting to move at around 3in/vac, up to about 16" when it stops moving. holds vacuum for 5 mins fine, no loss.

Would this point to a possible faulty turbocharger for these 0299/0101 codes?
TLDR: 2 codes. Replaced ripped S hose, N75 solenoid, all vacuum lines. verified VGT vac. actuator operation and ability to hold vac. Smoke tested under 8psi between turbo inlet and intake manifold intercooler connection with no visible leaks.
 

VariantB3_VR6

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EXAMPLE 1

YOu can see where the actual boost (yellow) was following the specified boost (green), then just kinda fell off at a gear change, then it's 2nd climb (yellow) and fall, then third climb, car dropped into LIMPO mode. and EMISSIONS WORKSHOP triggered. RED is rpm. I cycled ignition, and continued on, clearing the limp mode..


EXAMPLE 2


EXAMPLE 3

Example 3, the first call for boost (in a parking lot) was fine. the 2nd call for boost (middle of graph) was pulling out onto the road. Boost (actual) never made it to specified, and Limp Mode was triggered.

In VCDS, I went into Engine, into Tests, and tested N75 connected to VNT actuator (VNTA) and it worked as expected, with the actuator arm moving about a 1/2" stroke each cycle. Retested with the VNTA disconnected, and a VAC gauge connected to the VNTA port of the N75, and saw cycles of 22inHg - 0inHg, as expected.

So, this leads me to believe that it is, indeed, a turbo issue, since no leaks in charge air tubes was detected in smoke/pressure tests..
Your thoughts?
 

zzdiesel

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Just a thought here. Peraps Tee in a vacuum gage and see what the actual vacuum is while driving and when it goes into limp mode. You could try it before and after the N75. Does it still have the catylytic convertor?
 

oilhammer

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There are just too many to list....
If you've ruled out the control side (vacuum source, check valve, N75, VNT actuator, etc.) and you've ruled out the charge air side (boost leaks), then you should be able to SEE or HEAR the turbocharger itself as being physically broken. And when a turbocharger dies, it typically does so in a spectacular fashion, because they normally spin at tens of thousands or RPMs. So take the inlet tube off, and look in and see if the compressor wheel has blown up or if the unit will not turn.
 

VariantB3_VR6

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If you've ruled out the control side (vacuum source, check valve, N75, VNT actuator, etc.) and you've ruled out the charge air side (boost leaks), then you should be able to SEE or HEAR the turbocharger itself as being physically broken. And when a turbocharger dies, it typically does so in a spectacular fashion, because they normally spin at tens of thousands or RPMs. So take the inlet tube off, and look in and see if the compressor wheel has blown up or if the unit will not turn.
That's the thing... it turns, and has no play in the shaft... It's so damned confusing..
 

Scubanero

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8 psi is only 550 mbar and you don't lose boost until up over 2000. I would try a higher pressure smoke test.
It seems to me that if the turbo wheel/shaft assembly was toast, you would never get any boost.
 

VariantB3_VR6

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That's what's weird.. it'll make boost, then fall off.. I'll try to do a higher boost leak test today.. I'm working with limited, homemade boost test tools and a homemade smoke tester :D
 
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