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Allroad semi auto prob

Discussion in 'A6/S6/Allroad forum (C5 Chassis)' started by Delboy73, Oct 25, 2012.

  1. Delboy73
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    Delboy73 New Member

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    [Oct 25, 2012]
    Bought a 2004 allroad 3 wks ago and have been happy with it.
    The problem is that this morning driving to work the semi auto mode would not activate.
    Had to drive in full auto and that seemed to over rev on take off. Stopped after 5 miles and restarted car and all seemed fine.
    Also in full auto the display was not showing what drive mode i was in s....d....r......n.....p for example.
    Would like some feedback as the car is still under warranty.
    It's a 2.5tdi 2004.
    Thanks
    #1
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  3. TYphoon GB
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    TYphoon GB Member

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    [Oct 26, 2012]
    The box is driven by a mechatronic unit immersed in the oil.
    These suffer from 'dry joints' and solenoid failures.
    A Vag Com scan should show any faults.
    First off check date of last box oil and filter change. Many people get a return to normal after a oil change.
    Otherwise its a new module (about £2K) or a rework by ECU Testing (about £500 including a local independant fitting as the oil is £100 on its own).

    Audi A4 A6 PRNDS light flashing - Audi Faults

    If you do get a vag com error then ECU will test the device for about £40 to £50.

    If there are no errors this may not prove the unit is good but start looking at the wiring and the external sensors feeding the box.

    Good luck killed 2 on my DSG TT luckily all on warranty!!
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  4. Delboy73
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    Delboy73 New Member

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    [Oct 26, 2012]
    Thanks mate I'll get it scanned.
    #3
  5. ms1083
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    ms1083 Member

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    [Oct 28, 2012]
    Def get it diagnosed whilst under warranty, i have had to have a new gearbox = very expensive.

    Another issues it may be, which is quite a lot cheaper, but still would be diagnosable by reading fault codes is the selector lever. Inside the unit there is a circuit board which can fail. Mine is tempremental, worse on cold damp mornings. It means the car's electronics is unable to know which gear you have selected. Apparantly this normally happens few years after someone drops a drink over the area and the electronics start to corrode.

    ALso, the selector mechanism contains little magnets which move across the circuit board, again to identify which setting is selected, these magnets can drop out of their carrier meaning however much you move the lever the electronics are unaware of your choice. This probablly won't get picked up by fault scanning but easy to check & fix yourself.
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  6. Delboy73
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    Delboy73 New Member

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    [Oct 29, 2012]
    make contact with the garage and they say they will call me when they have arranged a courtesy car.The car has a few issues I want looked at.With it having a short warranty(three months) I want this done ASAP.Thanks for your input.
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