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Oh no the dreaded immobiliser thread!!!!

Discussion in 'A4/S4 forum(B5 Chassis)' started by madkebab, Dec 29, 2005.

  1. madkebab
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    madkebab Member

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    Well I suppose it had to happen some when, I have been struck down with the dreaded immobilser problem.

    Went to use the car just before xmas, I hadnt used the car for probably 10 days and the battery didnt have enough charge to turn the car over. So I put the battery on charge (whilst still connected to the car).

    Anyhow left on charge for an hour came back and car started first time. However, after filling up with petrol the car wouldnt start again. It would run for like 3 seconds and then cut out with the immobilser light on the dash flashing.

    Only way I could get it to start was to disconnect the earth on the battery and then reconnect and restart the engine. I managed to home but if I wanted to use the car I would have do the same routine of disconnecting the battery. I decided to give the battery a full charge overnight (battery still connected to car).

    The next morning the car wouldnt start at all whatever I tried.

    Do you think that charging the battery whilst it was connected to the car has somehow blown the immobilser? Has anyone else experienced problems whilst charging the battery on the car?

    I have phoned lots of well known Audi specialists and all have said I will need to take the car to the main dealers to get this sorted out. God knows how much this will cost and they cant even get the car booked in until 11th January.

    What I am going to try is to swop out my ECU and replace it with a spare I bought ages ago off of Ebay (non-chipped though). I have ordered the VAG-COM USB interface as I know you have to reprogram the immobilser after an ECU change. Hopefully this might cure the problem. If anyone has any other ideas please let me know. Is it possible to disable the immobilser altogether and go for a 3rd party one?

    This is really doing my head in as I know that mechanically the car is fine its just some blooding annoying electronics stopping it from running.

    Just think what is going to happen to more recent cars when they get to 10 years old with electronics managing everything!!!
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  2. FezzR
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    FezzR Member

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    first thing to do before you start pulling anything out,
    do a diagnostic check, interogate the fault memory on 01 - engine, 25 - immobilizer, and 17 - dash pannel

    if it is the immobilizer blocking the engine then it should throw a fault code, along the lines of "incorrect key programming" and or " engine control unit blocked"

    if no faults does it start if you blip the throttle when starting, sometime in really cold weather if the coolant temp sensor has failed then there is nowhere near enough fuel to even start.

    If it is an immobilizer problem first thing to do is to take down the steering column shroud and lower dash trim follow the wires from reader coil on the key end of the ignition switch. remove these wires from the main loom all the way to the immobilizer and insulate them seperately and route them as far from the main loom as possible.
    The reason for this is because interference from the ignition switch during cranking is known to upset the immobilizer, very well known cause and cheap to fix yourself.

    Hope this helps
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  3. imported_mc119856
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    imported_mc119856 Guest

    Had the same problem recently, started off very intermittent & would usualy fix itself after a few goes at turning the key. Then it got much worse, it would'nt start at all but like you i disconnected the battery to cure this. As time went on it got much worse & twice i needed a tow home.

    So eventually was so pi$$ed off i took it to Audi who charged about £250 to fit a new immobilser coil. The bad news is that its integrated into to ignition barrel so
    i had to wait 2 weeks for the part to arrive.

    My advice, forget faffing around with another ecu, take it to you main dealer & get it diagnosed/fixed. It may not be cheap but it definately beats being stuck in a petrol station!
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  4. madkebab
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    madkebab Member

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    Cheers for your responses guys, I will wait until my OBD cable arrives to see if there are any faults and take it from there. I am dubious about letting the main dealer touch my car as I have heard some horror stories about my local dealer.

    Has anyone else had problems after charging the battery on their car whilst still connected to the car? Is this safe or should I have disconnected it from the car first?

    The strange thing is most ppl who have experienced this problem say that it gradually gets worse over time. I had never had this problem before until I charged the battery.
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  5. FezzR
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    FezzR Member

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    charging the battery shouldnt cause you any problems, its usually jump starting that causes power spike and therefore problems

    althought it is possible with a low quality charger
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  6. madkebab
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    madkebab Member

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    right I have VAG'd the car. The following fault code has been logged

    01177 - Engine Control Unit
    65-10 - unauthorized - Intermittent

    Any ideas?

    I have a spare ECU so may try to see if I get the same problem.
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  7. FezzR
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    FezzR Member

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    you will get the same problem,

    that is saying that the immobilizer is cutting off the ECU,

    interogate 17 dash pannel and 25 immobil.
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  8. madkebab
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    madkebab Member

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    Well just to let you know I have resolved this problem. Hooked the car up to VAG-COM and followed the procedure as if I was replacing the ECU (which I didnt do) which resyncs the ECU and immobiliser. Car now back to how it was before. No trip to the dealers and didn't cost me any more than the OBD cable and the software. VAG-COM is priceless in these situations.
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