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Haldex controller question

jojo Nov 19, 2013

  1. jojo

    jojo Looking for Boost! Staff Member Moderator Team Daytona Audi S3 quattro Audi A6 Audi Avant Owner Group

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    Not your usual question, but would it be ok to just plug my Haldex performance controller under the car without bolting it up? No oil running through it, just want to eliminate the no comms DTC from VCDS. Shouldn't't be a problem right? The part is kind of expensive to break, so want to make sure!
     
  2. hoffmanvp3

    hoffmanvp3 Active Member VCDS Map User

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    Did u check the earth strap for the controller that's still bolted on?
    I don't see why the pre charge pump won't come on if your not requesting it to operate via VCDS but sure one will correct me if I'm wrong:)
     
  3. jojo

    jojo Looking for Boost! Staff Member Moderator Team Daytona Audi S3 quattro Audi A6 Audi Avant Owner Group

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    My car doesn't have an earth strap as far as I know? VCDS is just showing no comms to controller, so I wanted to plug my unfitted performance one on to test the comms. Will the lack of oil effect it's operation, it's just a stepper motor that opens and close a valve right?
     
  4. hoffmanvp3

    hoffmanvp3 Active Member VCDS Map User

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    Not really sure tbh but there should be an earth strap iirc as that'll prob be causing ur no coms
     
  5. Gops

    Gops Badger 5 Edition VCDS Map User Gold Supporter Audi S3

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    It should work.. But be warned not to turn over the car.. It'll piss out oil! I'm not sure if the pre charge pump activates on ignition and oil may come out! It's not a hard job popping it back out anyhow. You using MY blue haldex? :cool:
     
  6. jojo

    jojo Looking for Boost! Staff Member Moderator Team Daytona Audi S3 quattro Audi A6 Audi Avant Owner Group

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    I'm keeping my original Haldex in situ, just want to plug the performance one into the lead to confirm it's the lead that's faulty.

    It did come off your car, but it Miiiiine! :moa:
     
  7. Big Al

    Big Al Active Member

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    Hi Joe

    The Haldex controller may work if just plugged in, but without an earth it may malfunction and damage the circuitry. Apparently many of the controllers fail in this way, as earth straps often break. Your diff unit should have an earth strap and they are easy enough to make. There should be screw posts on both the shell and trans. See this picture of my Haldex unit which I'm selling.

    Al

    [​IMG]
    [​IMG]
     
  8. Gops

    Gops Badger 5 Edition VCDS Map User Gold Supporter Audi S3

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    Pre facelifts didn't have an earth strap
     
  9. Big Al

    Big Al Active Member

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    Really? That's weird. Maybe the loom wiring on pre-facelifts is different too, including an earth in the wiring? I can't see how the controller would operate reliably without the earth/-ve ground strap.
     
  10. rupe

    rupe A3 TQS In Devon

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    my facelift doesn't have a ground strap either and theirs no evidence of their ever having been one, I can see the stud on the floor pan where it would go, but it's covered in the factory underbody stuff.
     
  11. Matt78

    Matt78 Member

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    I'm having my Y plate S3 looked at tomorrow because of this same no comms code....
     

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