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Fault code 17608 Boost Pressure Control Valve

Discussion in 'A3/S3 Forum (8L Chassis)' started by Coless3, Jan 1, 2013.

  1. Coless3
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    Coless3 Member

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    [Jan 1, 2013]
    Hi all,

    Does this fault code mean I need to replace the n249 valve or is it my forge008 needing a service? Anyone got any other ideas?

    Cheers Coless3
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 1, 2013]
    Have you got an N249 bypass?

    <tuffty/>
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  4. Coless3
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    Coless3 Member

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    [Jan 1, 2013]
    No I haven't. Am I right in thinking that the n249 valve dumps the boost or not?
    Is it best to do a bypass? Won't it mean that the fault code is there continually if the n249 is bypassed or am I wrong

    coless3
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  5. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 1, 2013]
    That fault code is the result of the ECU trying to use the N249 to operate the dump valve under boost as there is an issue somewhere (typically an over boost deviation)... if the ECU doesn't see the boost pressure drop quickly enough (or at all) then this code is thrown as it implies there is an issue with the dump valve...

    If you have not done an N249 bypass then it suggests the DV is the problem.. I would look at that in the first instance...

    <tuffty/>
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  6. Coless3
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    Coless3 Member

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    [Jan 1, 2013]
    What's the reason for a n249 bypass? I have a forge 008 fitted, should I service it? Could this solve the problem?
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  7. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 1, 2013]
    N249 bypass is more suited to highly tuned setups... big turbo power etc... it also serves to clean up the engine bay if thats what you wish to do.. for stage 1/2 levels of tune it is not really thats required to be done but it does improve DV response a little...

    Its a protection system that is used by the ECU to prevent engine damage from an overboost situation...

    I couldn't say for sure if servicing the 008 will 'fix' your problem as the very fact that this has come up in the first place is because of another potential issue requiring the ECU to try and dump boost... service the DV anyway as they do require this from time to time, make sure that its actually working too... if you are getting a fluttering sound (choo, choo, choo noise) when you lift off the throttle (even revving the engine whilst stood still will highlight this) then the DV is not working properly so check it and the way its plumbed in

    <tuffty/>
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  8. Coless3
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    Coless3 Member

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    [Jan 1, 2013]
    Cheers for that, I know this is properly a silly question and there properly is an endless amount of things it could be but what would make the ECU try to dump boost?
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  9. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 1, 2013]
    ...as I explained above... too high a boost deviation... if actual boost is higher than requested boost by 200mbar or more for a set amount of time then it will try and dump boost and throttle cut to protect the engine...

    <tuffty/>
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  10. Gizmo20VT
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    Gizmo20VT Member

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    [Jan 1, 2013]
    Error codes and logs would point you in the right direction :), could be anything from a small boost/vac leak, to a faulty electronic component.
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  11. Coless3
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    Coless3 Member

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    [Jan 1, 2013]
    Gizmo20vt

    what would I be looking for in the logs? Would this highlight where the problem is coming from?
    is there set values for what certain things should be running at whilst looking at a log?
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  12. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 1, 2013]
    You need to log block 115 as a minimum... this will give you requested boost vs actual boost

    <tuffty/>
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  13. Coless3
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    Coless3 Member

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    [Jan 1, 2013]
    So if my actual boost is higher then then the requested boost what would I be looking at then?
    Last edited: Jan 1, 2013
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  14. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 1, 2013]
    If this is the case then you have a mechanical problem....

    One issue at a time though... fix the DV issue then start logging...

    <tuffty/>
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  15. Coless3
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    Coless3 Member

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    [Jan 2, 2013]
    Have taken out the DV and serviced it and checked it is working as far as i can. Did a log block 115 and as far as i can tell the actual boost pressure and desired boost pressure are all within 200mbar.
    Results were at 5760rpm ;- Actual boost pressure was 2190mbar and desired boost pressure was 2180mbar.
    Could the problem just be a faulty N249 valve? Is there any way of testing it?
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  16. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 2, 2013]
    Not particularly...

    I assume the code hasn't come back and the car is running ok? if so I would not worry too much about it at this time... if you are sure the boost is ok (what gear did you do the logging in?) then I would wait and see if you get the code again

    <tuffty/>
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  17. Coless3
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    Coless3 Member

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    [Jan 2, 2013]
    3rd gear ? does that boost pressure sound about right?
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  18. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 2, 2013]
    Would need to see the logs tbh...

    <tuffty/>
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  19. Coless3
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    Coless3 Member

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    [Jan 2, 2013]
    i haven't got them with me atm, would you mind looking at them tomo night.
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  20. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Jan 2, 2013]
    Sure...

    <tuffty/>
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