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rear diff controller .. audi s2 avant vaccum

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  • rear diff controller .. audi s2 avant vaccum

    Which of the 2 vaccumlines goes on what intake on the diff acctuator.?
    Yellow and blue line?

    I mean the plastic part the like an accutator. 20210212_152002.jpg

    vaccum lines.jpg
    If i look here. I have a standalone ECU , so think pink line i do not use.
    I dont have a A/C ,, so i should have 1 "pink" line from intake the check valve ( where is its location? )
    The vaccum rerservoir is what exactly ?
    And the rear diff controller is what ( where is it ? )
    As i read the picture .. the blue and yellow vaccum line on the first picture is coming from the rear diff controller correct ?

  • #2
    In coupe the check valve and diff controller are under the rear bench. I believe the Avant is the same?

    S2 Coupe 3B Project

    Ur quattro restoration

    S2 Avant

    Boost is the new rock and roll!


    • #3
      I think you can just check and try it out, if you connect it wrong you will open the diff instead of closing it when you push the "Lock Diff" .
      Then just swap around.


      • #4
        Hi ,, just made a little film on how my lines are connected ,,, it does not look like in the film i did....

        The green line for the ECU i dont have/need , i have standalone ECU with another vaccum line.

        I dont have AC on the car.

        Where is the vaccum reservoir ?

        The blue/white line has been cut at the controller , why do you think and what does that cabel do ?


        • #5
          It's a long time since i've looked at this stuff , but I'd say that the blue/white line is tied to speed and supposed to disable diff at "x", cutting this wire if i'm remembering correctly would mean you could still have diff engaged at speeds above whatever "x" was supposed to be , potentially dangerous but i'm sure it had been done/tried a few times with various results.

          apologies in advance if the above is incorrect , but ther's something familiar about the blue/white wire, somebody will know ...


          • #6
            White/blue wire is vehicle speed signal line. If you cut it, difflock control unit does not see moving speed and does not know when to disengage lock so keeps it locked until you switch it off manually.