1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

ECU Swap help...

Ram Aug 26, 2008

  1. Ram

    Ram Member

    Hi guys - I have a 1999 S4 and two matched ECUs...

    I want to swap the current ECU over with the spare to carry out some diagnostics.

    Bear in mind that BOTH ECUs have been matched with the cluster; what is the procedure please for adapting the swapped ECU so the car starts?

    Looked on Ross-Tech.com and the associated Wiki to no avail.

    Thanks in advance!

    Best wishes,

  2. Ram

    Ram Member

    Immobilizer 2 ECU Swapping
    Updated 29 Mar. 2005

    Ross-Tech is not responsible for any damage or problems that may result from following these instructions. They are to be used at your own risk. As always, you should refer to a Factory Repair Manual for your vehicle!

    Immobilizer II:

    The immobilizer will prevent the car from running without a matching key microchip. There is a symbol in the instrument cluster showing a key inside a car. If a new (or different ECU) is installed in the vehicle, the immobilizer will prevent the car from running and will cause the symbol to flash. Here is the procedure to introduce a new ECU to the instrument cluster. This must be performed each time ECU's are exchanged. This does not apply to installing a "chip" in the same ECU that is already aligned with the car.

    Immo-3 knows your car's VIN. Access 17-Instruments (or separate 25-Immobilizer on vehicles that are set up that way) and look at the first "Extra" field.

    If you see something like: "Immo-ID VWZ7Z0W0648696" You've got Immo-2 (or maybe even Immo-1 in earlier non-US models).

    If you see something like "WVZKB58001H231169 VWZ7Z0W0648696" You've got
    Immo-3. The first 17-digit string is the VIN. The second 14-digit string in the Immo-ID.


    Install the new ECU in the car
    [17 - Instruments]
    [Adaptation - 10]
    Leave channel at "00"


    [Done, Go Back]
    [Close Controller, Go Back - 06]


    Turn ignition OFF for 15 seconds. Start vehicle.

    Note: For cars with a separate Immobilizer (Includes 2000+ EuroVan, Cabrio, and many older non-US models), use [25 Immobilizer] instead of [17 - Instruments]. The rest of the procedure is the same.
  3. stapo69

    stapo69 All hail the mighty quattro!

    When I've swapped my ecu's over in the past I used steps 1 to 3 as above on vagcom. Dead easy.
  4. Ram

    Ram Member

    Perfect - Thank you! You don't happen to have a spare 551C by any chance do you??

    Best wishes,


Share This Page