How many different ecu's?

[S4evr]

There is A box, M box, are there any other ecu's? Which ones go with what year/vin car?

[tike0rz]

Dude check out S4wiki..I think that has what you're looking for.

[twinsnailsS4]

You're missing H box (2001), T box (2002), and then there are separate designations for tips (B, J, L, AA). The A box and M box are for 2000 and 2001.5, respectively.

[hosmer79]

I found this when looking for myself before on GIAC's website
http://www.giacusa.com/programs.php?mpid=59

2002 B5 S4® (Tip) 8D0907551AA
2002 B5 S4® 8D0907551T
2002 B5 S4® 8D0907551T
2001 B5 S4® (Tip) 8D0907551J
2001 B5 S4® (Tip) 8D0907551L
2001 B5 S4® 8D0907551M
2001 B5 S4® 8D0907551H
2001 B5 S4® 8D0907551M
2000 B5 S4® (Tip) 8D0907551B

Not positive which 2001 ECU Letters are for 2001.5 (if there even is a difference). I know my 2001.5 tip had the "L" ECU.

Take care!

[ThirdStrike]

is it true that M box is the fastest/best?

[twinsnailsS4]

is it true that M box is the fastest/best?

If you've searched and have been here long enough you will know that ECU and year is irrelevant...color is what ultimately dictates what's fastest

If you were being serious, it depends on what you mean by best and how you look at fastest. Strictly speaking in stock terms, 2000 S4's were a little lighter than newer ones and did't have ESP which could make it faster and better depending on what you want to do. Once mods are in the picture, I know for a while it was believed certain programming ran better on certain years, and with certain Stage 3 kits the Bosch MAF needs to be replaced, so in some sense the later S4's are better. At the end of the day, there's bigger things besides ECU and year that I would be concerned with...like color