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A4 tdi power loss in the rain

twist123 Nov 23, 2009

  1. twist123

    twist123 Member

    Hi guys,

    Hi Guys,

    My girlfriends 51 A4 tdi has loss of power when it rains heavily, never when its not raining, so im guessing its a connector thats getting wet or the EGR valve?

    List of things I need to check that Ive found on here are:

    Grease MAF contact
    Injector wiring harness
    N75 valve
    EGR solenoid and valve
    Fuel filter (doubt its this as only in the rain)
    Coil packs (doubt its this as only in the rain)

    Anything else to look out for?

    Many thanks
    Last edited: Nov 23, 2009
  2. BILKO1

    BILKO1 Member

    Can't answer your question but a VCDS scan might show up something. If you girlfriends car is a tdi i will not have coil packs.
  3. twist123

    twist123 Member

    I must really start thinking before typing away. Thanks for your advice.
  4. trigger999

    trigger999 New Member

    Hi there

    Firstly i am new to this forum stuff so forgive me if there is anything wrong here.

    I have exact same problem. A4 avant sport 1.9tdi AVF 2004 goes into limp mode when raining heavily. Happened 4 times now every time on motorway. Also suspect a wiring short of some kind by i'm no mechanic.

    Had a scan done 18047 throttle position sensor 1/2 G79 & G185 implausible signal. But its not the pedal sensor as i have changed this for a new part and still not fixed. I know that G79 and G185 are the two potentiometers and i think these are on the pedal.

    After about and hour or two - just enough time to get towed home, the car dries out and with the heat from the engine bay dash lights go off and drives like normal. Hope this helps with your problem twist 123. In the meantime does anyone know how i can isolate this problem.

    Is there anyone out there who can analyse the diagnostic in more detail?

    Do i check the wiring loom from the pedal to the brainbox if so what voltages should i be looking for.

    Any other ideas would be appreciated.

  5. laffind

    laffind Ticha

    Same problem egr etc done also mad n turbo changed but still happens
  6. Scottk

    Scottk Active Member VCDS Map User quattro Audi A6

    Have you checked the plenum chamber? Unlikely, but may be full of water if they haven't been cleaned for a while. Usually causes with carpets.
  7. chris_90

    chris_90 Member

    I had this problem and recently fixed it, check the bungs are removed around the battery and brake servo so water can flow out, after doing this I still had issues, so I removed the ECU cover and it turned out the seal wasn't on it properly so re sealed it and its been fine ever since. I didn't have wet carpets like many but clearly water was getting in there enough to cause an issue.

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