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Limp Mode

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by Oddie, Jul 4, 2012.

  1. Oddie
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    Oddie Member

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    [Jul 4, 2012]
    Over the last few days my car has started going into "limp mode". This morning i was entering the motorway and was in a bit of a rush so i put my foot down in 5th gear, i was only doing about 50-65 and about 2-3.5 RPM and the car just lost all power as if it had cut the turbo off. For the rest of the journey it just felt really flat and lifeless, as though it had no turbo.

    It also did it a few nights ago this time in 4th gear accelerating hard up to about 40ish again at relatively low RPM. It seems to do it when i accelerate hard in the higher gears.

    Now each time there has been no warning lights at all?

    I don't have access to VCDS unfortunately.

    Any help or ideas would be gladly appreciated, cheers.
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  3. Administrators
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    Administrators Administrator Staff Member Administrator

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    [Jul 4, 2012]
    My bet would be Air Mass If you turn the ignition off and back on it will clear. You might find that if your on a long hill and you accelerate from a low RPM it does the same.

    Have you looked in the VCDS section to see if there is anyone near you?

    Beck of luck

    A
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  4. Oddie
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    Oddie Member

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    [Jul 4, 2012]
    Yep, If I power the car off and back on again it drives perfect once again, full power. Does this sound like MAF then ? Forgot to add that it is a 2007 2.0 TDI 140

    Do MAF faults not produce a warning/error light ?
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  5. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 4, 2012]
    What engine?

    ** correction** just seen...
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  6. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 4, 2012]
    IIRC The 2.0tdi also has variable geometry turbos (as the 1.9tdi did).

    It could be that these have become caked up and stuck. But as Adam has said, without a VCDS scan it is difficult to tell.
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  7. Oddie
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    Oddie Member

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    [Jul 4, 2012]
    If that is the case how would i go about resolving it ?
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  8. Jeeves
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    Jeeves quattronly

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    [Jul 4, 2012]
    Could be that your TDI box is set too aggresively and causing some variables to exceed their allowed values. Worth speaking to them again to enable you to turn it down a notch or two.

    You don't want to be going into limp mode in the middle of an overtake.
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  9. Oddie
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    Oddie Member

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    [Jul 4, 2012]
    Hi mate, i have taken the tuning box off a few days ago
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  10. Oddie
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    Oddie Member

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    [Jul 4, 2012]
    Just spoke to a chap at Awesome GTI and he said it is almost certainly the turbo sticking. He was adamant that a faulty MAF couldn't cause this sort of behaviour. I am hoping and praying that it is the MAF, can anyone shed any more light ?
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  11. AR-rkon
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    AR-rkon BZZZZ.... caffeine fueled electrical engineer Regional Rep

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    [Jul 4, 2012]
    If you can get a vcds or diagnostic scan done and a "positive deviation" code comes up, it will be the vanes...
    #10
  12. Oddie
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    Oddie Member

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    [Jul 9, 2012]
    Sorry to bump this thread again but i have just had a interesting phone call with a mechanic who i have used for a few years. He said judging by the symptoms it doesnt neccesarily mean that the turbo is goosed. He said it could be the turbo boost pressure sensor, split pipe, wastegate sticking etc.

    Now from reading on various forums and speaking to several people, almost everyone seems to think that it requires a new turbo because the vanes are sticking.

    Any ideas folks ?
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  13. bez101
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    bez101 Yorkshire & Humber Rep. Regional Rep VCDS Map User

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    [Jul 9, 2012]
    it could be anything
    have you had a scan done yet to see if you have any fault codes ?
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  14. Oddie
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    Oddie Member

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    [Jul 9, 2012]
    Not yet no, i have just ordered a fault code reader so as soon as that comes i will get it scanned and see what it says. Forgot to add that last night i drove it hard and forced it into limp mode, turning it off and back on again and it was fine as usual.

    I drove it hard again and this time the engine management light came on and has now stayed on. Does this make much difference ?
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  15. mm707
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    mm707 Member

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