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boost fluctuation at low revs (p1200) boost control valve fault code

Discussion in 'A3/S3 Forum (8L Chassis)' started by 4rings, Sep 28, 2011.

  1. 4rings

    4rings Member

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    hi all. i have done some research and have found out that that fault code points to the n249 valve. so i rang up audi and said i need a n249 valve and there saying there is 2 of them?? how can there be 2 different valves under the same name??

    my car is a aum engine code 1.8t


    if anyone can shed any light on the subject would be much appreciated :)



    thanks
     
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  3. 4rings

    4rings Member

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    or could it be the forge split-r valve causing the problem?? would that cause boost fluctuation at low revs??
     
  4. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    17608/P1200/004608 - Ross-Tech Wiki

    17608/P1200/004608 - Boost Pressure Control Valve (N249): Mechanical Malfunction

    This fault code comes up when the ECU has made an attempt to operate the dump valve to dump boost as it wasn't a happy chappy (typically due to boost deviations of request vs actual and especially on remapped cars) and couldn't... basically the ECU spotted something it didn't like... operated the N249 but the boost didn't dump... This is one of those codes that normally symptomatic of another problem... I would suspect the N249 to be ok and the might be worth looking at the DV too...

    This fault code is fairly common where people have done an N249 bypass...

    There is only one N249 valve but should be noted that the reference 'N249' is its wiring diagram ref rather than a part number...

    If the N249 was electrically faulty it would throw an open or short circuit type fault code..

    What mods have you done to your car? aftermarket DV? remap? N249 bypas etc?

    <tuffty/>
     
  5. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    ah... the Forge Split-R... don't get me started lol...

    Swap this for a 007p or at least an OEM one... start from there...

    <tuffty/>
     
  6. 4rings

    4rings Member

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    ok thank you for the write up tuffty. the chances are it will be the split-r as i no they cause fault codes/ running issues. i will change for a 007p soon and go from there :)

    thanks
     
  7. Buzzer

    Buzzer Member

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    could it be the N75, it was the cause of my irregular boost
     
  8. <tuffty/>

    <tuffty/> Badger 5 Edition...Its all about the flow...
    Staff Member Moderator Audi S3

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    Needs logging.... too many variables as to why your boost is 'irregular' and the description is vague at best...

    In my experience when N75 valves are iffy they give boost spikes due to being slow to react to the initial spool, irregular boost could be anything from a vacuum leak or boost leak to a buggered turbo... AUM will have a K03s IIRC and these can and do wear out

    Only thing to do is to go over the basics to eliminate all the usual suspects such as boost and vacuum leaks and do logging to see what the ECU thinks is going on...

    Without that info its gonna be tricky to fault find..

    <tuffty/>
     

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