NefMoto

My car is EURO S4 B5 from 07/1999.
The ECU is 8D0 907 551D.

Remember the euro S4 B5 has immo in cluster (probably immo2, I 've never really known: but I'm sure the VIN number is not coded in the EEPROM cluster, only the immo ID AUZ7Zxxxxx )

I need a spare one and 8D0 907 551D is hard to find at a decent price.
Is there any other ECU that can match the original 8D0 907 551D ?
What about a a A6 ECU ? What's about immo (I would want to keep this feature ...)

What is the specificities of the 8D0 907 551D that justifies the D letter compared to C or M or G or K ?

Typically, a dumb example:
8D0 907 551G + bin from 8D0 907 551D can be a replacement of 8D0 907 551D ?

Hardware wise they are all the same. The trick is in the programming that is run on the ECU inside the box. While the programming governing the working of motor hadn't changed between the boxes at all or not much, certain ancillary items like addition of Immo in EU cars did.

To properly utilize an ECU that is foreign to your car, you'd have to re-program the EEPROM area of ECU with new VIN ID which is not something you can easily find software for, if at all. This was always dealer's domain. In theory VAG-COM/VCDS could do it but I think it requires some value that only dealer can supply anyway...

Sorry.

1) And If I bypass this step, what is the consequence technically wise ? Immo2 has not VIN coded in the cluster eeprom, only an immoID, so ?
2) I can unsolder the eeprom from ECU and doing it by hand, right ? Or is there checksum stuff in ECU eeprom ?

Note: I already read the cluster eeprom to retrieve the 4-digits PIN.

If put my current S4 file + ECU eeprom dump in the donor ECU (typically a A6 ECU with immo), should it work ?

I don't really catch where the road blocker is exactly.

Bump for this one, I'm really struggling to find a 551d or m to replace my c box. Was thinking could I not just use any ecu ie and a6 or 1.8t ecu and flash it with the Mbox file? As long as the pin out is the same and the size is the same it should be ok no?

APB 2.7 hardware is all the same, 1.8/2.8/4.2 ecu's are different. Any ecu from 00-02 (a6 or s4) will work regardless of transmission type it was originally equipped to handle (just make sure it's a 29f800bb flash chip, not the earlier 400). Just flash the file you want. I have some d-box bins I could send your way.

If you really can't find one, PM me. I've been stockpiling them.

excellent, cheers for that, gives me a wider scope of options. a6 2.7 ecus sometimes come up so ill take a look for them too

Would a 4B0907551F     0261206378-1037-350239         6mt EU  A6 AJK
 box be ok then? found one of these. though wiki doesnt say much about the 4B0 Fbox?

just an update, the above ecu has accepted a m box flash. will try this in the car and see what happens. cheers for the help