e30 m42 "175" ECU variations, how to decode white label ?

[m42roundie]

Ok, New to the forum and hoping to harvest some technical ifo from those in the know, here goes.

I have done a lot of searching and have found no info here or on the internets regarding the 90-91 318i / 318is "175" ECUs and the variations. Does anyone know how to decipher the white labels / stickers on the case?.

I have 4 1991 "175" ECUs but they are all slightly different inside, meaning slightly different circuit board layouts.

In other words they all have the same part number and all came out of 1991 318 series cars but are all different from one another. One unit even has a an additional circuit board standing on pins above the main board. what gives?

Can anyone shed light on this??

Thanks!-     Jeff

[1998ccc]

Not sure if it's a typo, but the "173" DME is for the M20 i motor.  The had quite a few different #'s and  single / two board styles for the i cars.  153 was 2 board, 173 / 380 / 525 etc were a few of the #'s that come to mind for the i's.

[m42roundie]

DOH,   typo indeed... now corrected!   thanks for the heads up!

[wazzu70]

If the PN is the same the ECUs should have the same functionality. If parts are not reverse compatible they will change the PN for tracking reasons.

The differences in PCB variations could be they are supplied by different manufacturers (different ways to get same end result), slight improvements, or changes due to part unavailability.