UrS6 & ABY ECU - Interchangeable ?

[macspring]

Are these car's respective ECU's interchangeable or are there differences that preclude swopping them about ?

Thanks.

[UrS4boy]

AAN ECU pin-out info with hyperlinks plus ABY pin-out

Are these car's respective ECU's interchangeable or are there differences that preclude swopping them about ? Thanks.

Prj will have the final word but I would say you can swap an ABY ECU into an AAN car easier than an AAN ECU into an ABY. The issue is the MFTS and how the two ECUs handle the over temp info via pin 46. (Used by the ABY ECU not used by the AAN ECU)

AAN ECU pin-out info with hyperlinks:

http://forums.quattroworld.com/s4s6/msgs/21009.phtml

ABY pinout info:

http://www.s2central.net/motronic_pinout_ABY.html

[A1QSHIP]

My S4 ECU is currently in my S6 with no issues.

[UrS4boy]

My S4 ECU is currently in my S6 with no issues.

The N American UrS4 and UrS6 both got the same ECU, 551AA, so that is not surprising.

Previously from prj:

"AAN Motronic ECU Part Numbers:
551A early UrS4 with pseudo dizzy and 8k boost chip
551AA UrS4 non-immo, Europe and America
551B UrS4 same as 551AA, but auto
551C UrS6 incorporates all software updates from RS2, different codebase, more diagnostics
551D UrS6 same as 551C but auto (see photos at the end of this post)
551E UrS6 has a small tweak to fuel on cold start
551F UrS6 same as 551E but auto.

[Nace20]

AAN ECU into an ABY. The issue is the MFTS and how the two ECUs handle the over temp info via pin 46. (Used by the ABY ECU not used by the AAN ECU)

I have AAn ecu in my S2 and works ok, at least i think

[varia]

I had aby in s4/s6.

[macspring]

Thanks for replies.

Ironically just re-found my stash of three spare ECUs.

macanmar will understand.

Two ABY and one AAN, so now for me the query is academic.

Thanks again though.

[UrS4boy]

AAN ECU pin-out info with hyperlinks:

http://forums.quattroworld.com/s4s6/msgs/21009.phtml

ABY pinout info:

http://www.s2central.net/motronic_pinout_ABY.html

I just checked the two pin-outs above against each other and other than Pin 46 and some pins involved with automatic transmission (AAN with autobox was available in the UrS4s and UrS6s), the two pin-outs are the same.

[mcandmar]

macanmar will understand.

Question is did you homefry the S6 ecu, or just take the ECU out of the blue S2?

[prj]

Both handle MFTS signal exactly the same.
They are interchangeable.

On AAN the MFTS signal simply isn't wired into the ECU plug.
Put it there, and it will behave just like ABY.