MS45 vs MS45.1

Besides some transmission lags at a certain RPM, is there anyone who knows what "fixes" were made...Dealer wants 430 to do the flash...Not sure that is worth it...I have the software to do it, but not the confidence nor a battery charger

MS43 vs MS45.1

MS43 has 3 wire MAF and a seperate AIT sensor in intake

MS45.1 has 5 wire MAF (that incorporates the MAF and AIT into one) and a seperate MAF on the SAP

DMEs and wiring harnesses are NOT interchangeable

I understand that...I'm asking about the diff between MS45 and 45.1...like what did BMW change to require this software upgrade....I have already realized that my car buying decision was bad when I read about the M56

I do not know of MS45 DME except when used with the M56 SULEV engine - so, in that case - the two DMEs are NOT interchangeable

Maybe I'm not explaining this properly...I have the M56 SULEV garbage motor....I have the MS45 DME...I'm trying to figure out what the MS45.1 software upgrade actually provides...I appreciate you trying to help though...That is a sick looking 330i

Originally Posted by NukeMiller

I understand that...I'm asking about the diff between MS45 and 45.1...like what did BMW change to require this software upgrade....I have already realized that my car buying decision was bad when I read about the M56

MS45.0 & MS45.1 DME's were introduced in the US Markets in 03/03 on both the 325i, 330i ZHP & SULEV. This ECU was then later used on the early 04-06 Z4 2.5 & E60 530i's as well. Since you have a M56 you are a SULEV BMW made this change for US Spec vehicles for cleaner Emission Purposes.

The Fuel Injection system in M56 is completely different than that of a M54.

I do not believe the MS45.1 DME will work on the M56 engine

As far as I know, MS45.0 = Europe and MS45.1 = US. Euro E46s never got either, but cars like the Z4 and E60 did get the MS45.

Originally Posted by TerraPhantm

As far as I know, MS45.0 = Europe and MS45.1 = US. Euro E46s never got either, but cars like the Z4 and E60 did get the MS45.

correct! MS45 is using narrowband sensor and MS45.1 is using wideband, therefore the parts aren´t interchangeable, as the hardware is different.

Right on...Thanks guys...no need for me to take action then...

Originally Posted by daniel_f.

correct! MS45 is using narrowband sensor and MS45.1 is using wideband, therefore the parts aren´t interchangeable, as the hardware is different.

Doing a little bit more research, in the US, the Z4 came with the MS45.0 as did the X3 2.5i (but oddly, the 3.0i got the MS45.1). You are correct in that the difference seems to be wideband vs narrowband sensors.

I have a MS45.1 laying around and i would like to do the convertion from MS43 to MS45. Does anyone know if there is a possibility to build an adapter between the stock MS43 harness and the MS45 ecu? i don´t want to re-pin all the wires directly.

Originally Posted by daniel_f.

I have a MS45.1 laying around and i would like to do the convertion from MS43 to MS45. Does anyone know if there is a possibility to build an adapter between the stock MS43 harness and the MS45 ecu? i don´t want to re-pin all the wires directly.

I'm sure you can reuse the vast majority of the stock harness, but some changes will still have to be made. Extra pins for wideband sensors, extra wiring for SAP MAF, and... Actually that's probably all. And unless you can tune your ECU, I imagine that you'd need to use the 5-pin MAF as its unlikely the MAF and its temperature sensor follow the same curves as the ms43 hardware.

I also suspect that the MS45.1 and MS45 are largely similar. I would not be surprise if you can convert from one to the other with a bootsector and program update.

Actually i don´t think BMW wanted the same hardware inside the DME, as wideband needs definately different hardware components. But as i haven´t opened a MS45.0 i´m not shure.

nevertheless i would prever the ms45.1 because of the capability using wideband.

i know which wires to change, i just don´t want to change the stock harness.

Eh, I'm 99.9% sure the hardware is the same. The pinouts are identical except that the MS45.1 models use a couple extra pins (corresponding to the extra wires required by wide band sensors). A DME that is meant for wide-band O2 sensors could be reprogrammed to use narrow-band sensors -- this wouldn't be particularly difficult if you have access to the source code as BMW does.