what is the difference between the boxes (ECUs)

[Turtle]

I know its a stupid question but the search came up with like 900 matches.... So like whats the difference between say an M-box or a H-box. How many different ones are there. Thanks

[10SecS4]

The B5 S4 came with the following ECUs in this country:

2000 6spd - A-Box
2001 6spd - H-Box
2001.5 6spd - M-Box
2002 6spd - T-Box

2000 tip - B-Box
2001 tip - J-Box
2001.5 tip - L-Box
2002 tip - AA-Box

6spd ECUs are not interchangeable with tiptronic ECUs (and vice-versa).

2000 ECUs are not compatible with other model years.

2001.5 ECUs and 2002 ECUs are directly interchangeable.

2001 ECUs can be interchangeable with 2001.5 and 2002 ECUs if you recode the instrument cluster. This is a simple procedure that takes about 30 seconds with a vag-com.

So the difference between the M-Box (2001.5 6spd) and H-Box (2001 6spd) is the different coding for the instrument cluster (which can be changed by recoding the instrument cluster module with the vag-com).

The box numbers, in case you're wondering, refer to the last character of the Audi part #.

Here is an example of an M-Box:

http://www.titsup-racing.com/video/parts4sale/mbox.jpg

Some ECUs have a VW/Audi/Skoda sticker on them that covers the original part number. The sticker has the original part number of the ECU along with an X at the end. These are remanufactured ECUs.

Some ECUs have a little arrow or triangle to the right of the part number. This means that the ECU did not come in the car from the factory and was purchased through the dealer.

Hope this helps.

[HighDesertAudi]

I wonder why the Auto Ecus don't work with the Manuals. On my old A4 I recoded a Auto Ecu to manual with VAGCOM.

[10SecS4]

You can't recode the transmission soft coding on S4 ECUs (not to be confused with TCU for all you tip guys out there). Been there, tried that. It just won't accept the change in the vag-com.

06611 for the 00 6sp
06711 for the 01 6sp
06651 for the 00 tip
06751 for the 01 tip

[Kievskiy]

^ hey marc, where can i find the info on my a6, which ecu is it, my sticker is messed up on the top of ecu, its 2000 2.7t a6 6mt? can you help?

[10SecS4]

You've got a K-Box son.

Audi part # 4B0 907 551 K. Bosch part # 0 261 206 561

Let me know if you need one as I've got a couple kicking around in my collection. [:D]

http://titsup-racing.com/images/s4/kbox.jpg

[HighDesertAudi]

You can't recode the transmission soft coding on S4 ECUs (not to be confused with TCU for all you tip guys out there). Been there, tried that. It just won't accept the change in the vag-com.

06611 for the 00 6sp
06711 for the 01 6sp
06651 for the 00 tip
06751 for the 01 tip

I ran an Auto ECU in my A4 for awhile, it ran good but would stumble when decelerating, and had a CEL for "Not being able to comunicate with my non-existant TCU). It was a simple fix with my A4.

I guess the S4's ECU most be more complex

[10SecS4]

The biggest problem is the difference in load value and characteristics between the two. When I put a 2000 6spd ECU (A-Box) in my 2000 tip S4 (B-Box car), the car was extremely unresponsive at low speeds (in addition to the TCU going into limp mode).

[Kievskiy]

^Thanx, are they stock/chipped(k-box)? how much?
pm me the info.