T5 losing power

[jimmyd]

Well I have just returned home from a 6400km trip from Brissy to Port Fairy and twice my van has lost power dramatically while driving at 100km up some of the hilly areas of Princess Highway. Not good when the van drops from 100km hour to about 30 while having huge semi's right up my tailgate. Both times as soon as I got to a safe spot and tuned the van off, it worked fine when started up again. The van is a 2005 2.5 auto , I have booked it in for a 40,000k service at German Auto's , but thought one of the experts here might have some ideas of whats going on
And have a happy and safe Christmas and New Year all, there really are some idiots out there on the roads !!

[gregozedobe]

Sounds a bit like the turbo's variable vanes might be sticking in the "high boost" position, then when the boost increases too much as the revs get up to 2,000 rpm or so; the ECU notices the "over boost" condition; so it puts the engine into "limp home" mode (to protect the engine from being blown up). It also records a fault code in the ECU.

When you switch the engine off off it resets and runs normally (until it happens next time). This problem tends to happen to 2.5 TDIs that are mostly driven very gently at lowish revs - when you do put your foot into it the above happens.

Best to get someone to look at the fault codes stored on the ECU - need VCDS (VagCom) or the dealer software tool to do this.

If it is overboosting and your van is covered by extended warranty then the dealer will probably just whack a brand new turbo on, but if you are paying for it it is much cheaper to pull the turbo apart and free up the vanes. If you do a search on "sticky vanes" there are several different descriptions around on how to do this, some quite detailed and with photos (IIRC the ones on the TDI Club forum are pretty good).

Hope that helps. Please let us know what the fault turns out to be, and what you ended up doing to fix it. This will help improve the corporate knowledge in the forum.

[jimmyd]

Thanks greg for your info, the first available spot I could get for a service was 22jan, so hopefully problem won't happen too much in the next month ! I think you might be spot on with it being the turbo, as some days the van seemed a bit sluggish when doing 100/110 done the highway, then next day it was flying. I took some advise i read here and let the engine idle for a few minutes after a long days drive, is this the right thing to do ? I will post results after the service..thanks again..j

[4wheels]

Hi Jimmy,

The driving behavior sounds similar to mine when it went into 'limp home' mode after a sensor failure. It was quite comfortable at 100km/hr on the flat, but didn't want to know about hills. Mine's a manual 4 motion, so maybe it was a bit easier to help along with the gears.
I ended up doing about 300km in limp mode to get to the dealer at Port Macquarie (with VW Assists 'OK'), and when they did the repair they found the DPF was 'beyond regenerating' and had to be replaced. I suspect this was because of maybe running rich in limp mode. Fortunately all covered by warranty, but $1500 for the DPF, and $2500 all up.
I guess you don't have to worry about a DPF, but I'd be wary of using it much if it stays in limp mode. When did your factory warranty run out? Maybe you can buy the extended warranty before VW find out (about your problem), but I think maybe it has to run continuously with the factory warranty.

Brian
2007 Trakkadu

PS. I had the 'engine check' light come on on the dash, did you? Might be an argument to get it seen to earlier, rather than just asking for a service.

[Jmac]

When the variable vanes stick it either under boosts or overboosts, both throw limp mode, take it for a drive and get it to happen, then turn the ign off, this gets rid of limp till next cycle, Fault will be logged if this is the case anyway
Cheers
Jmac

[jimmyd]

thanks guys, well I have had this happen twice in the last 3 months, and no fault light shows up on the dash. Not going to be driving the van very much now till it goes in for service, so I will post results then ..j

[gregozedobe]

I took some advise i read here and let the engine idle for a few minutes after a long days drive, is this the right thing to do ? I will post results after the service..thanks again..j

It is good to let a turbo cool down before you switch it off, and important to do so if it has been working particularly hard (eg going up a hill).

I find the easiest way is to just drive gently for the last 3-4 minutes of a journey, then you can switch off immediately.

If your problem IS actually sticky turbo vanes then AFAIK continued driving is unlikely to do much further damage, and you can sometimes avoid the overboost/limp home mode a bit by driving gently and keeping the engine revs below 2,000 rpm.

[Jmac]

It is good to let a turbo cool down before you switch it off, and important to do so if it has been working particularly hard (eg going up a hill).

I find the easiest way is to just drive gently for the last 3-4 minutes of a journey, then you can switch off immediately.

If your problem IS actually sticky turbo vanes then AFAIK continued driving is unlikely to do much further damage, and you can sometimes avoid the overboost/limp home mode a bit by driving gently and keeping the engine revs below 2,000 rpm.

Totally agree here, had the same issue with 1.9 golf the owner was 70 yrs old and never noticed the fault!!!!! sold it to a young fella and all of a sudden it rears its head
Cheers
Jmac

[jimmyd]

Totally agree here, had the same issue with 1.9 golf the owner was 70 yrs old and never noticed the fault!!!!! sold it to a young fella and all of a sudden it rears its head
Cheers
Jmac

thanks again guys, makes me feel a bit less worried. Not really a lead foot and maybe being a bit too careful when driving I didn't really think this would happen tho with the van having such low k's

[Umai Naa!!]

A few things can cause this fault. Dirty/carbon'd-up EGR and intake flap, sticking actuator on the turbo, or possibly even a cracked exhaust manifold.

I'm gonna take a stab and say that the fault code logged is P0299 Low Boost Pressure.

[Jmac]

A few things can cause this fault. Dirty/carbon'd-up EGR and intake flap, sticking actuator on the turbo, or possibly even a cracked exhaust manifold.

I'm gonna take a stab and say that the fault code logged is P0299 Low Boost Pressure.

What happens if it is boost pressure too high?? itll still limp mate, online and telephony diagnosis is dangerous mate, suggest it maybe wiser.
Cheers
Jmac

[jimmyd]

My van just had it's service, and after complete scan, no fault recorded as to why it went into limp home mode. Lawrence told me to bring it back in as soon as poss if it happens again so he can do a scan.

[jamwin]

My van just had it's service, and after complete scan, no fault recorded as to why it went into limp home mode. Lawrence told me to bring it back in as soon as poss if it happens again so he can do a scan.

Having the same problem with my 2010 Automatic Caravelle - problem is when I take it in to VW they turn it on Monday morning and the problem isn't there anymore. They said they have sent the codes to VW and didn't get a clear answer back, now they have 'recalibrated' but unable to replicate the problem at the garage. This is the second time we have brought it in, so I know if i just pay and pick it up I'll have the same problem again. Very frustrating as they don't know what is actually wrong with it.

The issue with being the guinea pig to see if it happens again is it might cause me to get in an accident with my 4 kids in the van so I'm actually terrified to drive the thing knowing it will happen again.

Have posted full details in another thread on TDIs: http://www.vwwatercooled.com/forums/...-54215-36.html

[Sunny43.5]

I can only ad this much to the issue as we have had some issues with our T5 2004 turbo , check ALL the vacumm hoses for any cracks . I had ours to a supposed reputable place NOT Jmac he is a legend but anyway this other mob replaced the turbo and returned the van with the same damn problem Grrrr I went on a journey into the engine bay and found a minute crack in one of the vacumm lines and voila fixed it instantly . These supposed experts not only missed the cracked tube but ended up doing $1200 worth of damage to the door sills by lifting the van at the wrong spots on a hoist .

[jamwin]

Have also tried contacting VW Australia directly - sent them an email and they sent back a form to fill out. Called and they said "we need to have a supervisor call you back", then no call back. Repeated attempts to contact them have failed.