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Thanks for all the replies. Car went into my local VW dealer today and guess what.......? They found nothing wrong with the car. They didn't find anything with the diagnostic check. Should I be surprised at this and seek a 2nd opinion?. To me this fault appeared quite serious when it happened.Luckily I wasn't overtaking at the time, but why hasn't the ECu stored details of the fault. It seemd as though the Turbo had completely gone.
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It possible that your MAF (mass air flow) sensor is faulty. In some cases this can cause the car to go into 'limp home mode' and thus disables the use of the turbo. Did the car run normally after this incident or only after you restarted it the next day or whatever ?
A faulty MAF is more evident at higher speeds because there's more air travelling across it.
It's also highly likely that this didn't show in the faults stored by the ECU as for some reason this component often doesn't.
Tell your garage you want to try a new MAF, it'll not be the first time they've had to do it !!!
CCC Technology
Performance Tuning
www.ccctech.co.uk
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The fault did occur at around 70 mph. It ran like a "bag of spanners" for the rest of the journey (approx. 3 miles). It only disappeared the next morning when I restarted the car after work.Thanks for the help.
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WW: have you tried cleaning the MAF? Might still be some tips on Freds. As a long shot, consider water in fuel: examining fuel filter would show this. Drain and replace filter if necessary. Cheap things first in the absence of intelligent diagnosis by VW. Odd how they seem to be stumped despite hundreds of failures of MAF, apparently.
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Hi CCC - I'm experiencing a similiar problem with my Passat TDI 90. It has a gradual loss of power which eventually culminates in me pulling over. After restarting the engine - its fine - for a while! Could this be the MAF? or A hose breakage? Needless to say it didn't misbehave while in the garage but the mechanic thought it might be the MAF, but at £180 plus labour I want to be sure!
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In the course of my TDi motoring, I've had several MAF's replaced, all after the performance had gradually degraded over a period of time (weeks, not hours). (Being overtaken uphill by a BT van suddenly makes it clear that performance has dropped off!). Never had one fail suddenly (touch wood) nor recover after switch off. Also, techicians at VW dealer said that TDi 'limp-home' mode really is slow - not 70mph max that my Golf suffered...
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I have a similar problem with a 1998 Golf 1.9GT Tdi 110BHP, it loses power within a few minutes of "decent" running on a fast road - OK for longer round town. Been to the main dealer and no diagnostic codes showing. Changed the AMM to no effect, changed the ECU to no effect. Their next suggestion is to change the Fuel Pump at a cost of many hundreds of pounds. I would welcome any alternative comments before I am bankrupt! It is not going into limp-home mode as it will eventually get up to speed and will rev to the red-line off load, but it feels just like someone has turned the turbo off like a switch - it is a sudden change, not gradual. Apart from this problem, I love the car and would happily but another...
Did you ever get to the root cause on the Passat?
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My problem was a "one-off" to a certain extent. The Dealer found nothing. However after my problem I felt the car wasn't pulling correctly. Put it back in this week and have been told it needs a new Turbo. Not actually convinced that this is the problem, but it is under warranty and I am more than happy for them to carry this work out.I believe that the symptoms of my problem are more likely to be caused by the wastegate sticking (causing turbo cut-out due to overpressure) or the MAF. However I'll go with the most expensive solution 1st. I'm so glad that VW have this 3 year Warranty or I would be skint.
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I bet it is something to do with the pump. The car mechanics magazine saw many articles where this has been the case on diesels, inc a passat and cavalier.
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I've had this on my Passat Tdi110. It was just after I bought it. After 280 miles on the motorway I pulled out to overtake a van and trailor and the turbo stopped working. A bit alarming, would have been potentially fatal if overtaking on single carriageway. I called the dealer, who basically didn't give a monkey's. The RAC, however, got to the bottom of the problem. The loss of pressure to the turbo was caused by a loose jubille clip on one of the turbo pipes. As the engine had got hotter and hotter, it expanded just enough to alow the pressure to drop to normal atmospheric pressure, hey presto, no turbo. Once it cools it tightens up a bit and the car works again. Check all the pipework on the turbo system and you'll probably find that the prat who assembled the car did not tighten something up properly. Because this is not a 'failure' it is not recognised by VW diagnostics, and, of course, when I took my car into the dealer on my return they said nothing was wrong. What was wrong was the fact that the dealership (VW franchise) had clearly not checked the car at all prior to sale. The message is clear - don't buy a VW.
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