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Passat ECU in A4?

Discussion in 'A4/S4 forum(B5 Chassis)' started by Foxmeister, May 4, 2011.

  1. Foxmeister
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    Foxmeister Fired Up!

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    Is it possible to fit and code a VW Passat ECU into our A4's? I know underneath the exterior the cars are alike, but im sure they have their differences which makes this not possible, or does it???

    Reason i ask is the charger kit came with the software installed on an ECU, from a V6 Passat, but its fitted onto an encryption type board, so cant be removed and re-used. Other than the above idea, the ECU and software are really no use then.

    Local GIAC dealer thinks i'd need to send my own ECU to GIAC in US of A to be done there, dont fancy posting it there though, doubt i'd see it again. Im currently in contact with PES also so see what they can offer also.
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  2. Broken Byzan
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    Broken Byzan Photographic Moderator Staff Member Moderator

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    My last car had an ECU form a Pissrat in it, but i did check and the part is fitted to both models of vehicle.

    What is the part number? Maybe we can cross reference it
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  3. Foxmeister
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    Foxmeister Fired Up!

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    Passat ECU is - 3B0 907 551 T

    No sure on my cars ecu, is it something you can find elsewhere??? Cheers.
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  4. Jason.s
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    Jason.s Active Member

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    Does indeed match. Passat, A6 and A4 1999 onwards for AQD and APR codes up to chassis 8D-X-400 000 (Audi) and 3B-X-600 000 (VW) and superseeded part number is 3B099752LX
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  5. Foxmeister
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    Foxmeister Fired Up!

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    Good stuff mate, thanks.

    However, my car is 1997, and not sure of my engine code, will have to check that. Provided the ECU matches eng code, will other suff matter like year, chassis no etc, or is that just details to tie ECU with that build date of cars?

    If it does work(fingers crossed) how do i go about having the ECU recoded to my car??? Where or who does this???
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  6. Jason.s
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    Jason.s Active Member

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    hhm well that number is for 99 onwards on most of the models but does drop to a 97 on a passat syncro which i didnt mention just because to actually get a passat that comes up as a syncro is rare even at work and the amount of passat details i put in each day is crazy seeing as the asians use them for taxi`s and the eastern europeans seem to love them and theres a lot of both round here lol.

    If you can get your chassis number i can see if it falls below that chassis break (which it should) and also what your engine code and ECU you`re currently using. Then maybe someone a bit more clued up can work out whether its going to do the trick or not.

    Im not sure myself if it can be done on VagCom, if not then it`ll be Audi themselves and you`d have to drive down there with your ecu on, swap it over and then fit the passat one once its recoded im guessing. Aragorn or Byzan will know for sure.
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  7. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    If its a '99> its probably drive by wire.

    your current car will probably be cable throttle.

    Compare the ECU plugs, if they're the same it should work, if they're different its likely a DBW ECU and you'll need to convert the car to DBW to use it.
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  8. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    As for coding it, theres a few different methods depending on which level of IMMO the ECU has onboard.

    If the ECU is IMMO1 or 2, you can recode it with vagcom pretty easily.

    If the ECU is IMMO3 you'll probably struggle to code it with your IMMO1 cluster, and will require the IMMO removed from the ECU.
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  9. Foxmeister
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    Foxmeister Fired Up!

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    Good shout Kev, hadnt thought of DBW etc. How can i tell which level immo i have, need to connect to Vagcom just???

    Okay, just had a look at my ecu and it looks pretty much identical, size shape and the plug ports, so hopefully its a DBC same as my 97 car??? Although part no's differ??? Is it just different from models normally even thou same unit???

    Heres some pics and chassis no

    [​IMG]

    [​IMG]

    Chassis no
    [​IMG]

    Can anybody confirm anything from that?

    Cheers for help so far guys.
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  10. Foxmeister
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    Foxmeister Fired Up!

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    Heres the Passat ecu to compare

    [​IMG]
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  11. Jason.s
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    Jason.s Active Member

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    The pic is cutting off the last number of your chassis no so i cant put it into ETKA lol. Not that it really matters too much

    Your chassis falls before the break of the passat ecu i posted further up too Yours being 8D-V and the break is UP to 8D-X

    Your ECU is listed for a ALG with manual box and has no chassis break on it and also is used on same age range passats so isnt audi specific. Oh and it goes up to 2001 in the A4 range so dont think this one matters if its DBW or not? Especially with no chassis break on it to say otherwise.
    Last edited: May 5, 2011
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  12. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    Presumably just means that all ALG engines were cable throttle.

    Plug it in and try it. Even without coding the immo it should start momentarily and then cut out.
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  13. Foxmeister
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    Foxmeister Fired Up!

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    Sorry mate, didnt even realise i cut off a digit! Doh!

    So basically the ECU should work with my car? Only issue now will be the coding of it?
    Last edited: May 8, 2011
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  14. Foxmeister
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    Foxmeister Fired Up!

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    I'll give it a bash later on then, wot can we take from it if it does? That the ECU is talking to my car ok and just the immo needs coding???

    Does anybody have Vagcom that can do the coding for me if this is all that i need???
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  15. Foxmeister
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    Foxmeister Fired Up!

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    More $hit news.

    Went to try plug in the Passat ECU to see if the car would fire up, but noticed the plug clips to be slightly different

    look the same here
    [​IMG]

    But connections from the looms are different style plugs and prongs
    [​IMG]

    [​IMG]

    With these being part of the PCB i take it im pretty much fecked at this point in trying to use the ECU or chip that i need.

    So, next possibilty is can i have the car live mapped once i install the supercharger to get the best possible out of the charger??? Or is there an issue with our ECU's to doing this?
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  16. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator

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    thats defo a DBW/DBC difference. The DBW ECU's have many more pins.

    You're either going to have to convert your engine to DBW, or find someone who can map the original ECU.

    Given the trouble we've had finding someone who can properly map the ECU in Marks 1.8T, i think you'll have big problems finding someone who can do the job properly. All i can suggest is have a chat with MRC and RTech and see what they suggest.
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