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02 TDI power problem Help - 1964johnr
My TDI drives well around town, but as soon as I hit the motorway and put my foot down , there is little power after 60mph. Foot to the boards to get to 7omph and big problems getting up hills. I have noticed that the gushing sound that I normally get when I turn the ignition on is no longer there. Could it be a fuel pump problem ? I have also read that it could be a MAF sensor problem. Anyone got any ideas ? I called the AA, but no faults came up on his diagnostic test with the lap top. I don't really want to take it to a VW dealer specialist and pay £100 an hour labour.

Edited by Webmaster on 09/02/2009 at 17:43

02 passat SE TDI power problem Help - adverse camber
Any smoke? What colour?

Is it only on hard acceleration or do you have any issues on light acceleration?

Can you narrow it down in terms of engine speed/road speed in different gears?

MAF fai;ure wont show an error. If you disconnect the maf do things get better or worse or no change?

02 passat SE TDI power problem Help - loskie
Sounds like similar symptoms to the MAF failure in my 1.9 tdi Octavia. Or sticky turbo Vanes?
02 passat SE TDI power problem Help - craig-pd130

Agree with Loskie, possibly a failed mass airflow sensor as these don't always show a fault code, even when they have failed.

Could also be sticking turbo vanes, although this usually manifests itself by performing normally until you give the car some beans ... and then the car overboosts, going into limp-home mode, which causes the glow-plug light to flash. If the car isn't running normally then suddenly losing power (like you've hit the brakes), it's unlikely to be this.

The turbo boost on Passats is controlled by engine vacuum and there are lots of small-diameter plastic hoses running around the engine. Have a check with a torch to ensure that none are loose / unconnected at the joints, this can happen quite easily. It's worth removing the plastic cover over the airbox (2 screws) to check under there, as there are several junctions.

Also have a quick look under the bonnet and make sure all the inlet / intercooler hoses are in place and not split. A known weak spot with the Passats is the "elbow" hose that runs from the intercooler up to the engine block. This can and does split; it can also get soft over time, which means it kinks. Check the bends in the hose for wrinkles / splits etc.

02 passat SE TDI power problem Help - 1964johnr

Thanks for the reply. I'll try all the things you mentioned. Can you explain what you mean by limp home mode. I don't hink I'm getting that. Everything seems okay until I hit 60mph, that's when I hit the problem. It's also intermitant. One time it's fine, the next I have the problem. I've been driving round town for a few weeks with no problems, but I never get over 40mph. There doesn't seem to be any problem with smoke from the exhaust, only the same small amount as usual. John.
02 passat SE TDI power problem Help - Giggles
Had this on my A6. Car was going into safe mode.
Turned out to be a pipe come off the turbo (leak-off I think).
Worst case the turbo is dead (is the car really smokey). If it is then park up and get your intercooler cleaned out or you'll have no engine left soon.
Also, like said before, try cleaning the MAF.

EDIT: Like the poster above also said, the elbow from my intercooler was also split.

Edited by Giggles on 09/02/2009 at 16:43

02 passat SE TDI power problem Help - 1964johnr
Thanks for your reply. I'll check under the hood and see if I can see any problems and clean the MAF. There are no problems with smoke. John.
02 passat SE TDI power problem Help - 1964johnr
Thanks for the reply. Problem only occurs when moving in to 4th or 5th gear. Occurs in these gears with light or heavy acceleration. I will try your idea of disconnecting the MAF wires and see what happens. I guess your getting at If the problem is not there with the MAF disconnected, it's probably the MAF causing the problem, if there is no change it's probably something else. I'm kind of hoping it is the MAF. I can change that myself and it will only be £70 for a Bosch replacement. Any ideas why I no longer have the gushing sound when I turn the ignition on. Could this indicate a fuel pump problem ?
Cheers, John
02 passat SE TDI power problem Help - adverse camber
I'm not quite sure what you mean by a gushing noise? Is this with ignition on but engine not started?

I think that a fuel pump problem would be more noticeable in driving.

I would have expected a hose problem to be more engine speed /load related rather than road speed. There is the turbo valve which could be problematic - again doesnt have to set the warning lights off.
02 passat SE TDI power problem Help - craig-pd130
you get the gushing sound when turning the key to start, it's the lift pump in the fuel tank priming the fuel lines.

Maybe part clogged fuel filter too?
02 passat SE TDI power problem Help - 1964johnr
Thanks for the info. When I get it sorted i'll post to say what the problem was. John.
02 TDI power problem Help - andythom
i had a similiar problem to this with my passat tdi and it turned out ti be the boost pressure control switch
02 TDI power problem Help - enigalive
1964johnr > I have exactly the same problem in my VW Passat TDi which I bought from meinheim auction. I have already tried driving bypassing MAF sensor with not much of a difference. Booked a full service with my local nationwide autocenter this weekend. Will see if it resolves the problem.

I would like an update on your problem. Have you managed to sort it out ?
appreciate your help :-)

02 TDI power problem Help - garygp3
I have had a power problem with my 2001 130 tdi sport for two years now. first time it happened I had driven hard for 40 miles and it went into limp mode, I drove another 90 miles and stoped in a garage for fuel. after paying the car was back to normal. this started to happen more and more often but it only happens if I go over 70mph. i found that by quickly switching the ignition off then back on again it resets the problem and is ok. the frequency is now so offten that i really can only drive at less than 70mph in order to keep full power. the car has been serviced regularly. there are no lights that come on. now i only drive at below 70mph and realy have a problem. i would like to sort the problem so if anyone knows what the problem is that would be great.
02 TDI power problem Help - craig-pd130

This sounds like overboost again. What revs are you doing when it goes into limp mode, and what gear are you usually in?

Is it usually 5th or 6th when the revs are around 2,500 for more than a couple of minutes?

One thing worth a try on Passats is to hose the VNT mechanism control linkage with WD40, it's quite exposed to rain & road muck and can get sticky.

If you know where the VNT actuator is (its the silver mushroom-shaped thing with a tube going into the top of it, on the LEFT side of the engine as you look at it, next to the airbox-to-turbo hose), have a feel underneath. There is a rod that goes from the actuator down into the turbo housing.

That rod moves the VNT linkage. What you need is a small can of WD40 with the straw on it. You need to aim the spray DOWN the rod so it runs down to the bottom of the linkage. REALLY soak it, then leave 15 minutes and soak it again. This can flush away crud that may be making the linkage sticky.

If that doesn't work, then it is likely that there's a problem with the N75 solenoid or the turbo is sooted up internally.
02 TDI power problem Help - garygp3
As you say, the revs are about 2,000 - 3000 in 6th gear and normally after at least 20 min driving although it happens sooner and more often each time. Today, after reading the comments above, I tried driving only in 2nd gear at about 4000rpm to try and put it into limp mode but it didn?t happen, maybe the journey was too short or it only happens in 6th gear?

When I accelerate hard and throttle off to change gear there is loads of smoke left behind, I don?t think it is blue or white it just looks dirty. It is really noticeable at night when there are lights behind you, the car behind almost disappears lol.

I will try the VNT actuator as you have suggested and see if that helps.

Thank you for your reply

02 TDI power problem Help - garygp3
Just to be sure!!

When the car goes into limp mode it is still drivable and will still get up to 70mph, it just takes a long time to get there, no real power and you couldn?t overtake with any confidence.

Not having experienced a car that goes into limp mode before I am only guessing that my definition above is actually limp mode and not some other problem.

02 TDI power problem Help - Glaikit Wee Scunner {P}
Why don't you search for a local independent VW group specialist and ask them to diagnose the problem?
Have a bit of discussion beforehand and tell them you do not want to waste your money. If they have any pride and knowledge they will take on the job and do it at a reasonable price.In my experience at much less than a main dealer. If you were in the South Yorkshire/North Derbyshire area I'd recommend JBS, Chesterfield.

02 TDI power problem Help - karak
Hi Craig,

I have read your posts in some tdi threads,and would like to ask for info about my 1.9 tdi pd bora with 130 bhp.
I have the same problem than some other guys here.
The car put it self to limp mode on the motoway,then switch off the engine,start again then goes well for a while,then the problem appears again.
My question is:
Do you know how to clean out the turbo on my car?I have seen you offer to use wd-40,which maybe solve the problem.
Could you give me a guide what and how to remove from the turbo(which pipes),where and how many times to spray the wd-40 please?

Thank you in advance

02 TDI power problem Help - craig-pd130


the WD40 thing is NOT a guaranteed fix but it is cheap and worth trying.

On the Golf / Bora the turbo is at the back of the engine, way down by the bulkhead on the passenger (left) side of the car.

You will need to remove the engine cover but don't remove any pipes. When you find the turbo, it's obvious where the actuator and rod are ... just aim for the short link arm that the actuator rod pushes / pulls on.

I have also seen on various forums that replacing the N75 valve (which controls the turbo VNT mechanism) can fix overboost. The N75 is the plastic solenoid switch on the bulkhead which has three rubber vac pipes and an electrical connector.
02 TDI power problem Help - karak
Hello Craig,

Thank you for responding!
I have tried to find the actuator.
Is it something like a rubber ball on the turbocharger?
So if it is,I only need to aim to the mechanical part of this?
I will give a try...
Someone told this horse power loosing can be caused a dirty or faulty MAF sensor.
Do you think should I try to clean it with brake cleaner?A mechanicer offered me this way.
02 TDI power problem Help - craig-pd130
This pic is useful -- it shows the turbo from underneath the car (Seat Ibiza, but the same engine and layout).


The actuator is the silver round thing pointing at you, and the actuator rod goes UP to the turbo, so you should be able to hose it with WD40 from above, if you remove the engine cover.

The MAF connector can be a problem and is worth a try, again it is very easy to get at. Brake cleaner is maybe too harsh, if you have some tape head cleaner, that's better.

Or you can just unplug and reconnect the connector 5 or 6 times. This will "wipe" the connector clean.

Edited by craig-pd130 on 24/11/2009 at 09:46

02 TDI power problem Help - karak
Hi there,and Thank you Craig!

I finally understood which could be this actuator rod!
I can not see from above,so I am going to get my self under the car,and will find it there.
Do you think I can try to move(pull-push) it whilst I am spraying with wd-40?
Or just spray it?
I am gonna check the vacuum pipes,and clean the MAF in the same time as well.

Then change the N75 and the MAF if the problem will still exist.

If none of them works,do you think is there a point to clean the whole turbo with Innotec Kit,or the turbo is probably dead?
Is there any way to clean the geometry(vanes) from outside without removing the turbo,or any pipes,or any parts from the turbo?

02 TDI power problem Help - dieselnut
When I had a MAF fail on one of theses engines it was a permanent fault & couldn't be reset by turning off the ignition.
Change all the vacuum pipes associated with the turbo & N75 valve. VW used poor quality rubber pipes that easily develop leaks & because they are covered in a cotton sheath you can't see the damage underneath, only costs a few pounds.
Make sure you change one at a time so you don't get them mixed up.
The turbo has to be removed & partially stripped down to clean.
Here is a link showing what's involved.
02 TDI power problem Help - garygp3
Finally I used the WD 40 on the actuator rod, I had driven some way so the turbo was hot. It made a crack noise and I was worried that it had cracked the turbo, it still ran ok so I think all is well. It has been well tested now and the car no longer trips into limp mode. I wish I had found this out 2 years ago when the problem first started. The power now is better but the economy has not changed, it is still really good. Thanks for all your help. Gary
02 TDI power problem Help - craig-pd130

that's good news, hope it continues to work without problems.
02 TDI power problem Help - ryxstar

Hello, I own a 02 plate vw passat 130 and I have noticed the power is gone after I rev up to 3500-4000 to over take someone as example. There is no smoke or any lights on the dash but, it is full power while I'm on the throttle and in the moment I change the gear, like 3-rth to 4-rth or 4rth to 5-th, right on the moment when I press the clutch I notice a small slow down on the acceleration. After the gear is changed, I have no power what so ever, it acts like an old diesel engine. The tricky part is that if I stop the car and put engine off and start again I have full power !!!! The car drives with no problems excepting the moment when I really want to put my foot down and leave it to go over 3500 rpm, which is not that often.

Recently I had service done, and the mechanic accidental pull off one of the vacuum pipes around the turbo and I had the same problem but was continuously, return to garage, pipe fitted back and problem solved. He drove the car before and after the pipe work and he felt the power.

Now, my question is, what can I do with the issue ? The mechanic test the car for error codes and it was clean. i do not want to replace parts just for fun.

02 TDI power problem Help - mickeybo
My TDI drives well around town, but as soon as I hit the motorway and put my foot down , there is little power after 60mph. Foot to the boards to get to 7omph and big problems getting up hills. I have noticed that the gushing sound that I normally get when I turn the ignition on is no longer there. Could it be a fuel pump problem ? I have also read that it could be a MAF sensor problem. Anyone got any ideas ? I called the AA, but no faults came up on his diagnostic test with the lap top. I don't really want to take it to a VW dealer specialist and pay £100 an hour labour.


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