MS42 < MS43 Compatibility Thread...
The purpose of this thread is to discuss and document the possibility of retrofitting a 323/328 equipped with the Siemens MS42 DME with an MS43 DME.
DME stands for Digital Motor Electronics. Its the European equivalent to ECU.
There were three versions of the Siemens DME offered with the e46 in North America, each with their own software packages which reflected the optional extras found in the car:
- MS42; used in the 323 and 328 M52TU engines
- MS43; used in the 325 and 330 M54 North American engines up to 03/2003; all 325xi
- MS45; used exclusively in North American for all M54 engines and SULEV engines produced after 03/2003; except all 325xi
The MS42 and MS43 have five harness connectors to handle the flow of data and power supply. They are referred to as "modules" and are numbered X60001 through X60005.
Pin Comparison Files (pdf format)
MS42(blue) vs MS43(red)
Module 1: X60001.pdf
Module 2: X60002.pdf
Module 3: X60003.pdf
Module 4: X60004.pdf
Module 5: X60005.pdf
Pin Location Reassignment: PIN_REASSIGNMENT.pdf
M52TU/M54 Part Comparison Spreadsheet: PART_NUMBER_COMPARISON.pdf
Its already known and documented that this DME swap can be done with the aid of an MS43 engine wiring harness. Our goal is to see if we can recycle the MS42 wiring harness, thus reducing cost and increasing accessibility.
This topic was initiated while discussing a viable solution to upgrade the M52TU to a larger throttle body located here:
Throttle Body Size (post b30 manifold swap)
More to follow...
This is a repost of JT_3K's research on the MS43 pin assignments:
Okay, heres a quick shopping list of the things we're going to need:
- Verify the above pin assignments are correct for the MS43
- Compile a list of the pin assignments in the MS42
- Compile a list of engine components which the DME directly interfaces with
Engine Components List (updated as new parts are suggested)
- Air intake temp sensor
- Ignition coils
- Crank angle sensor
- Cooling fan
- O2 sensors pre-cat
- O2 sensors post-cat
- Idle air control valve
If I missed something just say so!
Okay, well I decided to tackle the throttle wires. It's actually fairly simple once you have it on paper. Basically, any wires that stayed with the throttle body kept their original pins on the DME side. Any wires that had to be added/moved to the pedal module got new pins on X60004.
So here's the table. Format is:
EDK - MDK - X60003 (MS42/43) - Label
1 - 8 - 19 - A_DKG1
2 - 2 - 7 - U_DKG
3 - 9 - 43 - T_MDK1
4 - 5 - 10 - A_DKG2
5 - 10 - 44 - T_MDK2
6 - 4 - 20 - M_DKG
Discard all other MDK wires/pins
For the pedal, you're best off making a harness yourself. 6-wires
PWG - X60004 - Label
1 - 12 - M_FWG1
2 - 7 - M_FWG2
3 - 14 - U_FWG2
4 - 8 - A_FWG1
5 - 9 - U_FWG1
6 - 13 - A_FWG2
That is the bulk of the wiring difference. The other major difference is how various diagnostic signals are routed. It appears BMW just has the signals going directly to the cluster (or other module) instead of the DME sitting as a middle man. I have yet to verify this though, that'll be for another day.
X60002, and X60005 are identical between MS42 and MS43. X60001 has an extra voltage supply on Pin 9 for MS42 DMEs. Otherwise it is the same. Per the tables anyway. I guess we should verify the diagrams also look the same, but I doubt they'd switch polarities on us for no reason.
welllllllllllllll lookey here!
I just found a pin summary for the MS42 and MS43. It lists the pin locations and purpose for each of the five harnesses that plug into both DMEs. This will make this comparison MUCH easier!
TerraPhantm, sorry if this is what you've been talking about.
MS42 LHD 5-speed manual
MS43 LHD 5-speed manual up to 09/2001
MS43 LHD 5-speed manual after 09/2001
What version of the MS43 should we be using for this comparison? The MS42 didnt have very many options, but the MS43 looks like they had different year ranges.
Should we just make two tables?
And yeah the tables do make life easier, especially since the vast majority of the pins are in the same positions between the two modules.
Edit: also noticed that in addition to the differences I pointed out in my earlier post, they moved te signal for the SAP from pin 3 to pin 52 for some reason
Looks right to me.
okay, I edited the first posting and made a link for modules 1, 2, and 5 in pdf format. Heres module 3:
What on earth is a "suction jet pump shut-off valve"?
I'm pretty sure that's the SAP
aaannnnnddddd the last module:
Module 4: X60004
Seems Module 4 is where the issue lies...
Yes... its a cluster ****. From what I've gathered so far, it looks like there will have to be some pins that are shuffled between module 3 and 4.
I think before we go any further, it would be wise to have a cost-benefit discussion. I was browsing ebay today and found several M54 wiring harnesses for around 70-80 bucks. How much is it worth to someone to save 70 or 80 dollars by reusing the existing harness?
It's actually not that bad.
For the MDK/EDK stuff, post number 5 just about covers it.
On X60003, 6 pins from the MDK are retained (and just have to be rewired into the EDK connector at the TB side); the other 4 are discarded. And the SAP signal has to be switched from pin 3 to pin 52.
X60004 are where the pedal sensor/driver's wish connections ended up. You're best off just making your own harness for this. Its only 6 wires, and it's not particularly hard to route wires from the DME box to the firewall. Now what may prove to be problematic is the "fuel tank leak sensor" depending on what kind of hardware that requires... but someone retrofitting an MS43 harness would also have to retrofit that, so it may not be that big of a deal (or it doesn't throw a code). I would not worry about pin 18 - it's just for the butterfly valve in the 330 exhausts. It's completely optional (won't throw a code)
Now the other difference are the various diagnostic signals (battery, oil level, pressure, temperature, etc...) - we'll have to go through the diagrams to figure out what BMW did with them.
What parts of the harness would be hard to access? If they're that cheap, I'd rather do it that way as it should be relatively easy for me...I'm a "take things apart and put things back together" kind of person.
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