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Key Fob transponder failed

Discussion in 'A4/A4 cabriolet/S4 forum(B6 chassis)' started by murph2002, Mar 19, 2009.

  1. murph2002
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    murph2002 New Member

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    [Mar 19, 2009]
    One of my keys fobs looks to have failed. The remote part for opening the doors and boot works ok but when i put the key in the ignition it displays SAFE in the trip odometer. The car will start but shuts down after two seconds.

    I presume the immobilser unit within the car does not recognise the key and i need a new one. I phoned my local dealer who wants £160 pounds for a complete key assembly consisting of the front blade, rear remote section and coding to the car.

    Is the transponder in the blade section of the key ? .

    Is it possible to buy a genuine one elsewhere and get a local locksmith to cut it to match and code it via vagcom myself.

    The part number within the key on the remote part is 8Z0 837 231 D.
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  3. evilscotsman
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    evilscotsman Space Cowboy

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    [Mar 22, 2009]
    vagcom cant match keys mate. The keys are encoded to your dash module too, and only dealers have the ability to access the keycode depending on MY afaik.

    Have you tried replacing the battery? The car will accept one of its keys after battery replacement by opening the car with a working key, then placing the other key in the ignition, turn it on, then off, remove the key and immediately press the unlock button on the remote, then try locking and unlocking to see if the key now works in the ignition to start the car....mine was doing what yours does and I replaced the battery, it works fine now, still had to do the matching up bit as described above.

    Another weird story, is when I had my Alfa remote fob on the same keyring or in my pocket, the audi wouldnt recognise its own key and refused to start unless I put the alfa key away in the house....

    When you switch off the audi, the immob tells the key what the next transponder code sequence will be (encoded of course) and so when the battery is replaced the key tries a default code from the beginning so doesnt work, until the key is recognised and rematched by the car, and given the current code for the next engine start.
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  4. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Mar 22, 2009]
    The transponder doesnt have a battery mate. Its a RFID tag, and is a completely passive device, the RF signals from the barrel provide the power to allow it to transmit the ID

    Battery in the fob is only for the remote, and the two halves of the key come apart, leaving one have with just the remote, and the other half with the blade and transponder.

    An auto locksmith will have the kit required to recode the key to the car. VAGTacho can retrieve the SKC code from the clocks, and you can use that SKC along with vagcom to reprogram the keys.

    What i'd do is buy a genuine key from ebay from some other similar car (often breakers will put the keys online), Then fit your remote and blade to the repalcement key (so the only new part is the transponder), and get an auto locksmith to code it to the barrel
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  5. murph2002
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    murph2002 New Member

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    [Mar 23, 2009]
    cheers for the info, the remote section works ok and it does look like the transponder unit has failed.

    I am trying to find out if the warranty company will cover it first, if that fails then it looks like the ebay option.
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