Does an AAN ECU fit an ABY engine

[prosty]

Can I just switch the ECU's ? Are they compatible between each other? Or are there differences between the two?

[Jamo]

You need to check the numbers of the ECU

ABY had 2 ECU revisions ending in A & B IIRC

[prosty]

Okay but what are the differences in the ignition and fuel management? None IIRC? The tuning chips for S2 ABY / S4 / S6 are the same right??

[Jamo]

Okay but what are the differences in the ignition and fuel management? None IIRC? The tuning chips for S2 ABY / S4 / S6 are the same right??

AFAIK, the AAN & ABY ECU's are the same part number for the revision A

You just need to check your ECU as i'm not sre if the revision B is interchangable.

I'm only going on past post

[mcandmar]

Think there might be immobilizer versions but in short yes they are interchangeable. Only difference is in the mapping, from what i can tell the aan is a little more conservative in the mid range.

Interestingly my dad and i have been testing Paul Nugents homefrys in the S4, we have an ABY and AAN ecu homefried and both of us prefer the car on the ABY ecu. Main difference is part throttle below 4000rpms, the car pulls much better with the ABY chip.

Top end its hard to tell, didnt really notice much. Were also convinced the idle sounds different with the ABY chip as odd as it may seem.

[Knight Rider S4]

Doing the same thing tonight what is the easiest way to get into the ECU.same as the S4 carpet back then cover

[mcandmar]

Its a lot easier in an S2, ECU is stuck up the back of heater/glovebox. If you remove the trim under the dash you will see it.