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The point of this thread is to document some differences that should be known if one wishes to retrofit a Siemens MS43 DME into a vehicle that originally came with a Siemens MS45.1/MS45 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 and 330xi
  • MS45; used exclusively in North American for all M54 engines and SULEV engines produced after 03/2003; except all 325xi and 330xi
The MS43 and MS45 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.
Parts you will need to swap from MS45.1 to MS43:

-DME (obviously)
-MS43 engine harness
-Transmission/O2 sensor harness, whether you have a manual or automatic transmission
-MS43 MAF (doesn't have built-in IAT sensor)
-IAT sensor (intake air temperature)
-MS43 O2 sensors
-Coil pack harness

You can re-use your MS45 coil pack harness if you repin it.

Differences between MS43 and MS45 coil pack harness:

MS43:
Pin Type

1) E Signal Ignition coil 3 Ignition coil 3
2) E Signal Ignition coil 2 Ignition coil 2
3) E Signal Ignition coil 1 Ignition coil 1
4) Not used
5) M Ground Ground connector
6) Not used
7) E Signal Ignition coil 6 Ignition coil 6
8) E Signal Ignition coil 5 Ignition coil 5
9) E Signal Ignition coil 4 Ignition coil 4


MS45:
Pin Type

1) A Activation Ignition coil 5 Ignition coil 5
2) Not used
3) Not used
4) A Activation Ignition coil 3 Ignition coil 3
5) M Ground Ground point
6) A Activation Ignition coil 1 Ignition coil 1
7) A Activation Ignition coil 2 Ignition coil 2
8) A Activation Ignition coil 4 Ignition coil 4
9) A Activation Ignition coil 6 Ignition coil 6

Connector part # if you break the connector from repinning is: 12521744624

Differences at module X60004 (DME-body)

Pin 2:
Unused on MS43
MS45: Activation, heating for fuel tank leak diagnosis module

Pin 5:
Unused on MS43
MS45: Ground Secondary air, hot-film air mass meter (MAF for SAP)

Pin 10:
Unused on MS45
MS43: Signal Fuel pump relay 1

Pin 15:
Unused on MS43
MS45: Signal Secondary air, hot-film air mass meter (MAF for SAP)

Pin 18:
Unused on MS45
MS43: Signal Valve, exhaust flap M54 3.0 l only

Pin 19:
Unused on MS43
MS45: Activation E-box fan (fan to cool ECU compartment)

Pin 23:
Unused on MS45 (SULEV/M56 models? Because they are automatic only)
MS43: Signal Clutch switch

Pin 25:
Unused on MS43
MS45: Signal EAC (Environmental Air Catalyst) sensor (SULEV/M56B25)

Pin 31:
Unused on MS43
MS45: Local CAN-bus low / Control unit for electronically controlled fuel pump (SULEV/M56B25)

Pin 35:
Unused on MS43
MS45: Local CAN-bus high / Control unit for electronically controlled fuel pump (SULEV/M56B25)

If I find any new info, or anything needs to be corrected, I will update the post accordingly.
 

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The point of this thread is to document some differences that should be known if one wishes to retrofit a Siemens MS43 DME into a vehicle that originally came with a Siemens MS45.1/MS45 DME.



Parts you will need to swap from MS45.1 to MS43:

-DME (obviously)
-Transmission/O2 sensor harness
-MS43 MAF (doesn't have build-in IAT sensor
-IAT sensor (intake air temperature)
-MS43 O2 sensors
-Coil pack harness

You can re-use your MS45 coil pack harness if you repin it.

Differences between MS43 and MS45 coil pack harness:

MS43:
Pin Type

1) E Signal Ignition coil 3 Ignition coil 3
2) E Signal Ignition coil 2 Ignition coil 2
3) E Signal Ignition coil 1 Ignition coil 1
4) Not used
5) M Ground Ground connector
6) Not used
7) E Signal Ignition coil 6 Ignition coil 6
8) E Signal Ignition coil 5 Ignition coil 5
9) E Signal Ignition coil 4 Ignition coil 4


MS45:
Pin Type

1) A Activation Ignition coil 5 Ignition coil 5
2) Not used
3) Not used
4) A Activation Ignition coil 3 Ignition coil 3
5) M Ground Ground point
6) A Activation Ignition coil 1 Ignition coil 1
7) A Activation Ignition coil 2 Ignition coil 2
8) A Activation Ignition coil 4 Ignition coil 4
9) A Activation Ignition coil 6 Ignition coil 6

Connector part # if you break the connector from repinning is: 12521744624

Differences at module X60004 (DME-body)

Pin 2:
Unused on MS43
MS45: Activation, heating for fuel tank leak diagnosis module

Pin 5:
Unused on MS43
MS45: Ground Secondary air, hot-film air mass meter (MAF for SAP)

Pin 10:
Unused on MS45
MS43: Signal Fuel pump relay 1

Pin 15:
Unused on MS43
MS45: Signal Secondary air, hot-film air mass meter (MAF for SAP)

Pin 18:
Unused on MS45
MS43: Signal Valve, exhaust flap M54 3.0 l only

Pin 19:
Unused on MS43
MS45: Activation E-box fan (fan to cool ECU compartment)

Pin 23:
Unused on MS45
MS43: Signal Clutch switch

Pin 25:
Unused on MS43
MS45: Signal EAC (Environmental Air Catalyst) sensor (SULEV/M56B25)

Pin 31:
Unused on MS43
MS45: Local CAN-bus low / Control unit for electronically controlled fuel pump (SULEV/M56B25)

Pin 35:
Unused on MS43
MS45: Local CAN-bus high / Control unit for electronically controlled fuel pump (SULEV/M56B25)

If I find any new info, or anything needs to be corrected, I will update the post accordingly.
I understand everything except the transmission/02 sensor harness.... Does this apply for a manual transmission?
I know MS45 use different 02 sensor plugs.

Sent from my SM-G930P using Tapatalk
 

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Discussion Starter #3
I understand everything except the transmission/02 sensor harness.... Does this apply for a manual transmission?
I know MS45 use different 02 sensor plugs.

Sent from my SM-G930P using Tapatalk
Yes, you have to replace the transmission/02 sensor harness whether you have a manual or automatic transmission. The O2 sensor connectors are part of that harness.
 

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Yes, you have to replace the transmission/02 sensor harness whether you have a manual or automatic transmission. The O2 sensor connectors are part of that harness.
I have a wiring harness from a 330xi automatic. Would it work on my 6 speed?

Sent from my SM-G930P using Tapatalk
 

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Discussion Starter #6 (Edited)

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There should also be a number of different pins on X60003 as well. I don't have them handy, but I do know that a decent amount of them move around.
That harness might be easier to just replace with a new one, but it is definitely able to be done.
 

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Discussion Starter #8
There should also be a number of different pins on X60003 as well. I don't have them handy, but I do know that a decent amount of them move around.
That harness might be easier to just replace with a new one, but it is definitely able to be done.
Both the transmission and DME harness should just be replaced with MS43-compatible ones.
 

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VladBelsky, would you say it's easier to swap a MS45 to a MS43 this way or change the wire harness from a MS45 engine onto a MS43 engine? For clarity, I am doing an engine swap on a 325 MS45 and installing a M54B30 from a MS43... Any suggestions here or just do what you have listed above? I'd prefer to try and stick with the MS45 if possible. Thanks!
 

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Discussion Starter #10
VladBelsky, would you say it's easier to swap a MS45 to a MS43 this way or change the wire harness from a MS45 engine onto a MS43 engine? For clarity, I am doing an engine swap on a 325 MS45 and installing a M54B30 from a MS43... Any suggestions here or just do what you have listed above? I'd prefer to try and stick with the MS45 if possible. Thanks!
It would be easier to swap the MS45 harness onto the engine that has an MS43 harness on it, if you're swapping the engine into a car with MS45, but by a small margin. Only extra work that there really is with converting the entire car to MS43 from MS45 is swapping the transmission/O2 sensor harness, along with MS43-compatible sensors.
 

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Thank you for sharing all of this helpful information. I do have a question though in regards to the transmission/O2 sensor harness. I am in the process of swapping my car, which has MS45.1, to MS43. My car is a manual, so if I were to find a transmission/O2 sensor harness, would it need to originally be from a manual car? Also, I'm sorry if this is a stupid question, but are there any sensors/wires that run to the manual transmission? If so, how many and what are they? Thank you in advance.
 

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Discussion Starter #12
...My car is a manual, so if I were to find a transmission/O2 sensor harness, would it need to originally be from a manual car? Also, I'm sorry if this is a stupid question, but are there any sensors/wires that run to the manual transmission? If so, how many and what are they? Thank you in advance.
You would need a manual harness, yes. The only plug going to the transmission is for the reverse light sensor.
 

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Discussion Starter #15 (Edited)

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Hi everyone

David from the UK here
Ok
Car =z4 3.0i
DME ms45 (narrowband)

Parts I have

Ms43 dme, ews etc
Ms43 harness (full)
Maf & ait

However....
Has anyone done this yet though
Is the alternator voltage regulator got a solution yet, is it simply requiring the plug or new voltage regulator fur ms43?

Thankyou guys
 

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Discussion Starter #18 (Edited)
...
Is the alternator voltage regulator got a solution yet, is it simply requiring the plug or new voltage regulator fur ms43?

Thankyou guys
Get a male 3-pin EV1 connector, and make a splice with two (or all 3) pins going to the one wire on the oval female connector for the MS45 alternator.
 

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Hi guys if I may although an old thread apart from the alternator is there anything else that needs to be splised/ modified and also if I use my old intake do I have to make a hold for the intake temperature sensor as there isn't one of course.
Thanks.
 

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Can anyone comment on whether there are any negatives to swapping to MS43 from MS45.1? Is there anything in the car that doesnt work right after the swap? No issues with DSC working right or other electronics? Is the ONLY thing you give up is the wideband O2 sensors?
 
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