URQ 20v RR TPS Potentiometer conns

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  • predding
    S2Forum Enthusiast
    • Aug 2009
    • 132
    • Home: United Kingdom Current: France

    #1

    URQ 20v RR TPS Potentiometer conns

    Rather than continue on the old thread on RS2 I have started a new one as this speciically relates to the RR 20v

    I have now tested the TPS/idle switch and have the following readings BUT the wiring colours are different to the AAN / RS2 versionhere https://forums.quattroworld.com/s4s6/msgs/20405.phtml

    Mine are as below:

    Pin 1: Red / Black (RS2 Red)
    Pin 2: Purple/Black (Green/Black)
    Pin 3:Green / Blue (RS2 Grey)
    Pin 4:Brown / Yellow (RS2 Brown/Red)
    Pin 5: Empty (same)
    Pin 6:Green / Purple (RS2 Purple)

    See picture:

    Readings:

    Across Pin 4 and 6 on switch closed = 3800 Ohms (RS2 says 0 Ohms open circuit)
    Across Pin 4 and 6 on switch open = 2000 Ohms (RS2 infinite)

    Testing Potentiometer

    Across Pins 1 and 2 on switch = 2000 ohms (RS2 = 1500 to 2600)
    Across Pins 2 and 3: 800 ohms (RS2 = 750 - 1300 ohms)

    So on Pins 4 and 6 is the wiring different ie

    RR Pin 4 Brown / Yellow
    RS2 Pin 4 Brown / Red

    RR Pin 6 Green / Purple
    RS2 Pin 6 Pure Purple

    Question:
    Is the wiring still the same on the URQ RR as RS2
    If so, is my TPS Idle switch stuffed as it is reading 3800 ohms when acc to the test it should be 0 ohms open circuit

    The car symptoms are idling VERY rick but smooth
    Transition from idle to load big gulp/gasp and revs drop totally then come
    back
    Gentle increase in throttle position engine isnt smooth and some misfires

    This ties in with the exact description on the above link of what IT ISNT DOING
    "The switch tells the ECU what you are doing with your right foot, i.e. what the position of the throttle is at, it might even allow the ECU to check the speed at which you opened the throttle. The idle switch has two positions,idle and Wide Open Throttle (you can hear the microswitches click when you move the throttle body by hand with the engine off)."

    Thanks for any comments / feedback
    Attached Files
  • predding
    S2Forum Enthusiast
    • Aug 2009
    • 132
    • Home: United Kingdom Current: France

    #2
    No idea what is up with software on this forum but trying to deit and it wonts save and comes up with errors. So update on wiring is I found wiring diagram and imy notes check out with slight colour mod ie

    Pin 1: Red / Black (RS2 Red)
    Pin 2: Purple/Black (Green/Black)
    Pin 3:Grey / Blue (RS2 Grey)
    Pin 4:Brown / Yellow (RS2 Brown/Red)
    Pin 5: Empty (same)
    Pin 6:Green / Purple (RS2 Purple)

    So looks like the Idle microswitch in my TPS is stuffed. Question is can I take it apart and just fix that component?
    TPS wiring diagram Item G69 attached - I cross checked the wiring colours in German to my observations
    Attached Files

    Comment

    • Crasher
      S2Forum Enthusiast
      • Nov 2018
      • 139
      • Country: England

      #3
      I have the ABY wiring diagram at work, I will check. VAG tend to stick to a wiring protocol right across models. Have you checked the Lambda sensor voltage? Even a tiny air leak from the turbo flange gasket will cause air to be drawn in and pass over the sensor, making it produce 1 volt so the ECU starts adding fuel. This is a common problem with the OE MLS gasket so I use composite versions.


      Comment

      • newsh
        S2Forum Obsessed
        • Aug 2003
        • 16226
        • Country: United Kingdom

        #4
        Hi Paul
        You need to do this test with the TPS unplugged, is that how you're doing it?

        If so you definitely shouldn't be measuring a “resistance” in either open or closed.

        If the diagram above is correct for the UR20v then pin 4 to pin 6 is just a switch, open = infinite, closed = zero ohms.

        S2 Coupe 3B Project


        Ur quattro restoration

        S2 Avant

        Boost is the new rock and roll!
        sigpic

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        • newsh
          S2Forum Obsessed
          • Aug 2003
          • 16226
          • Country: United Kingdom

          #5
          Also make sure you have enough slack in the throttle cable to allow the switch to close. And the throttle stop hasn’t been bent or messed with.

          S2 Coupe 3B Project


          Ur quattro restoration

          S2 Avant

          Boost is the new rock and roll!
          sigpic

          Comment

          • predding
            S2Forum Enthusiast
            • Aug 2009
            • 132
            • Home: United Kingdom Current: France

            #6
            Hi Crasher & Rob, sorry for delayed reply as was on holidays. I will now try to locate the Lambda sensor and test the voltage, and the gasket.
            Rob - on the resistance this was with the connector removed and me operating the switch so I could hear it fully close click then open click
            I will go back and check again
            I have rebuilt everything and took it for a test drive, its still where it was 5 years ago ie if I press the throttle for accelleration, it gulps and just can keep up with the demand. If I ease the throtlle in, it slowly accellerates
            Last edited by predding; 6 September 2025, 09:13.

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