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VAG codes - Help Please ( bit long winded , sorry )

storm0906 Nov 25, 2009

  1. storm0906

    storm0906 New Member

    2004 A3 2.0 fsi sport.

    While driving the other day my car lost power and became unresponsive to throttle input ( travelling at 70mph in 6th gear ) I put my foot on the clutch and pressed down on the throttle and the engine revved freely, took my foot off the clutch and still no power. The power returned after a few seconds and was driving normally until it happened again when I was just at the top of a hill and took my foot off the throttle.
    When driving in town it has also started to lose & regain power, usually on a slight upward slope and when I have just changed gear from 1st to 2nd or from 2nd to 3rd. Has also lost power when on the flat in 3rd, 4th & 5th gear, usualy for a couple of seconds then power on for a second then no power again then it comes back and is fine.( has happened at various speeds between 20mph - 70mph )

    Pulled the codes and came up with.

    16825 - evap emission control
    16575 - fuel pressure sensor - plausible signal error
    18974 - low fuel pressure
    17480 - nox sensor

    Had the following done..
    Pressure tested fuel rail
    Cleaned rail pressure valve & sensor
    Stripped & cleaned throttle body & TPS
    Replaced fuel filter.
    Checked all connections & hoses ( none loose and no cracked hoses )

    Took it for a spin and the problem still exists but is now more frequent.

    Pulled codes again and only got.. 16575 - fuel pressure sensor - plausible signal error

    Power loss seems to only happen when engine is warm.
    Seems to happen only when you have eased your foot off the throttle and reapplied it.

    MIL has not come on before, during or after any power loss event.

    Probably coincidence ? but I have had 3 bulbs blown in the past week.

    Now thinking of replacing fuel pressure sensor but not sure if that will achieve anything ?

    Any ideas ?

  2. Ads

    Ads License to drive

    I've currently got the 16825 fault too. Cleared it a few times but it keeps coming back. Can't really say that I can feel anything wrong with the car though. Maybe the odd idle fluctuation from time to time, but no power loss or anything.
    Seems like this is quite a common fault on the fsi though. Seen it posted around quite a bit.

    Also had 16575, but read this can simply be caused by a low fuel level in your tank. Filled mine up, cleared fault, and it hasn't returned yet.

    Have you scanned again to see if any of the codes have reappeared since disappearing?? Mine took up to a week to come back. And once if threw up a slightly different code.
  3. storm0906

    storm0906 New Member

    Haven't got round to rescanning, last scan was this morning and only 16575 appeared. Have cleared that and waiting for the fault to appear again. Will probably rescan on Friday.

    Previous scans have all had , 16825, 16575, 18974.
    The second last one also had 17480

    The fault occurs regardless of how much fuel is in the tank.
    I have noticed that the idle speed is fluctuating when sitting in neutral, falls down to 650 rpm then back to just under 800 rpm.

    Intrestingly this problem only started to happen after I switched to using Shell V Power a month ago. Wonder if that could be upsetting some sensor or other ?

    Toying with the idea of putting in RON95 to see if that cures it. lol. But I know the emission sensors wont like that and the MIL will come on.


    The 2.0 fsi sport has been known to have issues with the Crank angle sensor,the crankshaft sensor and the coolant temperature sensor, i replaced these when i had my cambelt done and i dont get anymore error messages or idling problems but maybe i just got lucky :thumbsup:.
  5. Khufu

    Khufu Well-Known Member


    I've used Shell V in mine with no problems. Using Ron95 wont cause any problems with the MIL light etc, it will just retard the timing slightly meaning slightly less power/mpg but you wouldn't really notice it.
  6. storm0906

    storm0906 New Member

    When is the cambelt due ( is it 60,000 miles ? I've got 51,000 on the clock at the moment )
    Replaced coolant temp sensor months ago after the MIL coming on and the cooling fan running constantly.
    Crankshaft inspected earlier this month and found to be ok. No codes related to crankshaft being thrown up.

    Noticably less power / mpg And kept having activated charcoal filter codes coming up with the MIL on when running on RON95 along with the temp problem above.
  7. NHN

    NHN Retrofitter - Audi - VW - Skoda - Seat Site Sponsor VCDS Map User

    I would change the sensor then go from there as obviously if its not reading correctly it will have fairly adverse effects on the car.
  8. storm0906

    storm0906 New Member

    That was my thought, but what are the chances of the sensor being fine and the ECU being faulty ?

    Originally thought it might be the ESP kicking in and the ECU cutting the power but the ESP checks out ok with no relavant codes recorded ( or ESP light on dash when driving )

    New sensor ordered and hopefully fitted by the weekend.

    Thanks for all the comments everyone.:respekt:

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