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Thread: :: Fuel economy gauge...

  1. #1
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    Default :: Fuel economy gauge...

    Where does the dash fuel economy gauge take it's reading from?

    I notice mine is starting to act up (probably because it knows I'm going to by a TT). Sometimes it doesn't work. Sometimes it stays at zero (instead of off the side). Sometimes it just sit at a fixed position.

    I notice that when it's 'broken', the OBC readout in test mode and consumption mode is 0 as well.

    Any hints?
    :: HIDCanada.com | Illuminating Your World


  2. #2
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    I would like to know too. Mine wont go below 24. I remember reading somewhere that the electronics (capacitors?) in the dash went bad and it needs to be replaced. Im not sure if this is correct though.

    I hope there is a simpler, and cheaper solution...

  3. #3
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    If it's that, I don't mind as I have a spare clusterboard... but who knows. That would affect the OBC test group readout as well?
    :: HIDCanada.com | Illuminating Your World


  4. #4
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    I'm pretty sure the gauge takes input directly from the ECU. If it acts weird it can mean two things: either the gauge itself is malfunctioning or the ECU is doing some weird stuff. It woks on the basis of preset values in the ECU and not real world measurements of how much fuel is released by the injectors.
    2008 audi A3 1.9tdi
    (former 1991 520i LPG)

  5. #5
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    The OBC and Instrument cluster get information directly from the fuel gauge sender and speed sensor. I assumed these are processed within each unit to produce a fuel consumption figure. The OBC just gives a running average.

    I also think its likely the capacitors are at fault.

  6. #6
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    I had a problem with the mechanical movement of the gauge itself. The needle got stuck on something as it passed a certain point on its path. Try doing a cluster self test to see if the gauges move correctly then.

  7. #7
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    If it says zero MPG then it seems logical that it doesn't recognize the signal from the speed sensor telling the computer the car has moved.
    My '89 has a bum speed sensor(Ithink, the speedo is inop). I'll check and report what the OBC reports for fuel consumption.
    What is your speedo/odo doing??
    "The gas pedal wouldn't go to the floor if it weren't meant to be there"

  8. #8
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    My speedo and odo work fine. It's the econo gauge and OBC consumption and instant consumption (test mode) that shows nothing. Keep in mind doesn't always happen. Every once in a while since a few weeks back.
    :: HIDCanada.com | Illuminating Your World


  9. #9
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    Quote Originally Posted by myles
    I had a problem with the mechanical movement of the gauge itself. The needle got stuck on something as it passed a certain point on its path. Try doing a cluster self test to see if the gauges move correctly then.
    How do you perform a cluster sef test?

    Ralph Mendoza Jr. - Long Beach, CA

  10. #10
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    Hold in the check control button (the one on the right) as you turn the key from accessories to on, release the button when the test starts. If that doesn't work try holding the check control button while turning the key from off to accessories. The self test only works on cars with 02/89 and later instrument clusters.

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