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CentralLocking pump over-run

AlistairC Nov 13, 2008

  1. AlistairC

    AlistairC New Member

    When unlocking the car via remote, everything operates as normal.
    But as you get in you can hear the central locking pump still whirring away for another 10 or 15 seconds.

    Can anyone shed any light? It's just getting annoying now!
  2. S3quatt

    S3quatt Flat Oot like a ducks Foot VCDS Map User

    I've sometimes had this where the passenger door doesnt always unlock fully.

    I dont hear the pump running though but it registers on vag com as an overrun.

    If there's a whirring noise after you open the door this could be the fuel pump.
    I'f its on its way out, it could take longer to build pressure than normal...
  3. AlistairC

    AlistairC New Member

    3 weeks later and Pump is now dead.

    Have now done some more searching and as it turns out it is quite a regular problem.
    Over-run probably caused by a slight leak as expected.

    Problem is that over-run causes pump impeller to shatter as above.
    Now on the hunt for replacement parts before swmbo gets upset by using the keys to unlock.

    **For others who experience this - courtesy of Inigoj on the A4 forum**
    If the pump still runs, but doesnt create vacuum/pressure, it is most probable that the graphite impeller has shattered.

    This normally happens if there is a slight leak in one of the pipes, either at the front doors, the connector behind the drivers seat, or at the pump.

    The pump has to work overtime to attain the pressure/vacuum, and eventually becomes damaged.

    You can swap the pump for any with a similar part number and a suffix greater than 'A' (which doesnt have RF interface).

    Depending on where the pump is from you may or may not have to reset the central locking 'softcode' number.

    I am using a 'G' suffix pump from an A3 in my A4, and it did change the code number after fitting the replacement pump.

    If your pump is running for longer than 6 seconds, you have a vacuum/pressure leak in one of the tubes or tube junctions, normally the front doors, fuel flap or junctions behind the front seats. You can sometimes locate the leak by listening for a hissing noise inside the car.
    If a leak is not fixed promptly, and the pump continues to work overtime, the graphite impeller will eventually shatter and a replacement pump will be required.




    4A0 862 257 E


  4. Shug1874

    Shug1874 Member

    Exact same thing happened to mine. Got new pump, but still haven't found the leak, so pump isn't wired in anymore to keep it intact.
    Why couldn't audi use electrical systems like everyone else?
    Mind you, at 300 quid a pump I think I can guess....
  5. AlistairC

    AlistairC New Member

    Well pleased to say that the above diy fix seems to have done the job.
    Bought a pump from a 1992 Corrado G60, canibalised the motor & graphite pump & plumbed it in.
    All seems to work well with no leaks or over-run. £15 fix.


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