Different ECU's for same engine on other bodies?

[DaniTD]

Hi
I have a 318i 4-door with a M40 engine from 1990. My car has the ECU Bosch Nr: 0 261 200 157.
Now I have here another supposed M40 ECU with the reference Bosch Nr: 0 261 200 387.

The thing is, the later one has it's VIN on the sticker, and it came from a 318i cabrio. BUT, if I search the reference on ETK, it's supposed to be ONLY on tourings. And if I search with my car's VIN on ETK, this ECU is not listed for it.

BUT if I search on the BMW Nominal values and Specifications CD, they both appear as a valid ECU for all M40's with Motronic 1.3 management.

SO the question is, if they made variant codes for the ECU's to reduce the number of hardware to stock, why they made 2 different ECU hardware, if they have the same variant codes programmed (with/prepared for/without catalyst)? Maybe one is newer than the other? If so, why the ETK doesn't list it as a valid replacement for my car?

Strange german thinking

[Brianmoooore]

All interchangeable, except the M1.7 520 and 661 used on the E36, etc.
All M40 E30 ECUs were designed for lambda sensor equipped cars, and have a jumper plug in the engine loom to be plugged in when used without a sensor.

[DaniTD]

I know, but it's strange that ETK has ECU's for M40 in three groups:
-E30 coupé/sedan/cabriolet
-E30 touring
-E34 (of course, for the first ones using M1.3)

¿Maybe there is some different sensor? I can only understand differences on the M40 with M1.7 using a throttle potentiometer instead of a switch.

[Brianmoooore]

There may be minor differences between them, but they are all fully interchangeable with each other, with no differences in performance that will ever be noticed. Even the same ECU is loaded with different software for different markets. All sensors are the same on all models.