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2003 325Ci Convertible
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Discussion Starter · #1 · (Edited)
If you get into tuning your MS43 DME you will most likely want the ability to flash your ECU on the bench. (without plugging it into the car) It's convenient, especially for Full 512kb DME flashes, which would otherwise be a two-person job.

I spent a few days learning how to build my own cable, and I thought I'd share how to do that here. A lot of credit to the forums, especially to cwarel here on E46Fanatics, who posted a video (shown below) along with resources I used for building my cable.

What you will need
  • DME harness from a scrap car with MS43 DME
  • 12V Power Supply or Car Battery (Reliable. I used a PC PSU.)
  • Soldering/Crimping Tools & Knowledge, Basic Electrical Knowledge
  • Female OBD2 Connector (I used this one. I’ve found them as cheap as $0.99)
  • Wires for Connecting Harnesses
  • [Optional] Continuity Meter / Voltmeter (For figuring out which pin is which, this will help a lot!)

How to build your bench harness (Schematic Below)
  1. Take a look at your OBD2 harness and figure out which wires correspond to Pins 4, 7 & 16. A continuity meter will help here. Pin 4 is Ground, 7 is K-line, 16 is Battery Positive.
  2. Grab the DME harness you removed from the scrap car and disassemble it. Keep Plugs 1 & 4. Remove Plugs 2, 3 & 5.
  3. Take look at Plug 4 from the DME harness. Figure out which wires go to pin 32 (K-Line) and pin 26 (Battery Power). On every e46 I’ve seen K-Line (P32) is white with purple stripes and Battery Power (P26) is green with purple stripes. This DOES NOT mean that your car will have the same colors: Double-check or risk a bricked DME.
  4. Take look at Plug 1 from the DME harness. Figure out which wires go to pins 1, 7 & 8 (Battery Power) and pins 4, 5 & 6 (Chassis Ground).
  5. Grab your soldering iron or electrical crimps, we will be making a lot of connections. Make sure your connections are good. If these come loose during a flash, you may end up with a bricked DME.
  6. Connect together all your Battery Power leads (Pin 16 from you OBD2, Pins 1, 7 & 8 from DME Plug 1, and Pin 26 from DME Plug 4, and the +12VDC Lead)
  7. [Optional] I put a switch on the line going to the positive DME pins to emulation ignition for use with JMGarage Flasher, but it is not necessary (as seen in schematic)
  8. Connect together all your Chassis ground leads (Pin 4 from you OBD2, Pins 4, 5 & 6 from DME Plug 1, and the -12VDC Lead)
  9. Connect together all your K-Line leads (Pin 7 from you OBD2, Pin 3 from DME Plug 1 and Pin 32 from DME Plug 4)
  10. Shrink wrap / tape all of your connections to prevent shorts
Now you have a cable you can use to bench flash your DME! No more fumbling around in the car!

How to use your cable
  1. Plug in your power supply or connect battery (12VDC Leads)
  2. Plug your DME into the harness you built
  3. Connect your configured K-DCAN Cable to your PC
  4. Plug your K-DCAN Cable into your bench harness
  5. If you put in a switch, turn it on to emulate switching on the ignition. Without it, the DME will behave as if the ignition is on all the time
  6. Use Galleto, JMGarage Flasher, or Chipster MSS5x Flasher as you normally would

Wiring Schematic


Additional Resources / Troubleshooting

Notes!!!
  • As always, I am not liable if you mess up your DME using this guide. Please take precaution to avoid screwing things up.
  • PLEASE, for the love of god, use a RELIABLE Power Supply with enough amperage to power the DME. (See “What you will need”) If your PSU fails during a flash you could very easily end up with a bricked DME. This is more important than even the quality of your solder/crimp joints.
  • It’s helpful to flash a DME from the Junkers for your tuning purposes. Any Siemens MS43 ECU works, part numbers don’t really matter. This way you’ll have a “known good” DME with stock firmware is you mess up.
  • If your are just tuning your DME you DO NOT have to put your ECU into boot mode. Opening up your DME increases your risk on bricking (destroying) your DME. Only open your DME any put it in boot mode when using JMGarage Flasher.
 

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Thanks for the diy. I posted it in the ms43 tuning thread a while back but that got lost with the thousands of posts. You don't need a 5A power supply, my power supply from harbor freight outputs about 1A and does the job just fine. I've probably done 30+ flashes
 

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Discussion Starter · #3 ·
Thanks, I'll go ahead and update that now, I can remember where i stumbled across that amperage rating. I thought better safe than sorry.
 

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Looking for options for a cheap portable power supply for this. Any suggestions?
 

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Looking for options for a cheap portable power supply for this. Any suggestions?
I've been using this for all of my projects but for DME flashing, you can just use a harbor freight battery charger
 

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So.... after reading the whole topic, i managed again to get ignition and battery light showing up in INPA.
But everytime im trying to start my 12V supplie, its dying.


My 12V getting killed everytime I put the ignition pin in it.. Why?
Without i cant see ignition button in INPA, with it, my 12V is diying...

jesus this makes me going crazy like the last 4 days...pls help xd
I've done the same wiring as above in the picture shown
 

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xMoses, you need to connect the power first then the ground with your power supply already on. On my power supply if I have the power and ground connected and plug it in, my power supply won't power on
 

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Discussion Starter · #9 ·
That's interesting... where did you guys purchase your power supplies? I've never had that problem but I also have a toggle switch wired inline...
 

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On the diagram, what is that slash thru the power connection going to the DME supposed to mean? Is that supposed to be the optional ignition switch?
 

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Can somebody post photos of your bench wiring, what goes where? Because when I am looking over internet, everybody has it connected differently.. Do I need to connect wires from T4 ? I saw some guy just connecting 1ground,1 12V and 1 k-line from T1 going to inpa cable and to battery and everything worked fine, he didnt have any wire from T4.. Is it possible ? Thanks for answers, I am total noob in this :D
 

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Hello, does anyone know how to add the EWS module to this setup? I have done the following wiring:


EWS pin 4 -> DME x60004 pin 33
EWS pin 9 -> ground
EWS pin 10,11 -> Power supply
EWS pin 13 -> K-Line

After doing this INPA or the MSx flasher tool can not communicate with the module. Any ideas?
 

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Discussion Starter · #14 ·
@egoy936 In this setup I assume your DME is power and you connected the EWS K line to the DME K lines correct?
 

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If you get into tuning your MS43 DME you will most likely want the ability to flash your ECU on the bench. (without plugging it into the car) It's convenient, especially for Full 512kb DME flashes, which would otherwise be a two-person job.

I spent a few days learning how to build my own cable, and I thought I'd share how to do that here. A lot of credit to the forums, especially to cwarel here on E46Fanatics, who posted a video (shown below) along with resources I used for building my cable.

What you will need
  • DME harness from a scrap car with MS43 DME
  • 12V Power Supply or Car Battery (Reliable. I used a PC PSU.)
  • Soldering/Crimping Tools & Knowledge, Basic Electrical Knowledge
  • Female OBD2 Connector (I used this one. I’ve found them as cheap as $0.99)
  • Wires for Connecting Harnesses
  • [Optional] Continuity Meter / Voltmeter (For figuring out which pin is which, this will help a lot!)

How to build your bench harness (Schematic Below)
  1. Take a look at your OBD2 harness and figure out which wires correspond to Pins 4, 7 & 16. A continuity meter will help here. Pin 4 is Ground, 7 is K-line, 16 is Battery Positive.
  2. Grab the DME harness you removed from the scrap car and disassemble it. Keep Plugs 1 & 4. Remove Plugs 2, 3 & 5.
  3. Take look at Plug 4 from the DME harness. Figure out which wires go to pin 32 (K-Line) and pin 26 (Battery Power). On every e46 I’ve seen K-Line (P32) is white with purple stripes and Battery Power (P26) is green with purple stripes. This DOES NOT mean that your car will have the same colors: Double-check or risk a bricked DME.
  4. Take look at Plug 1 from the DME harness. Figure out which wires go to pins 1, 7 & 8 (Battery Power) and pins 4, 5 & 6 (Chassis Ground).
  5. Grab your soldering iron or electrical crimps, we will be making a lot of connections. Make sure your connections are good. If these come loose during a flash, you may end up with a bricked DME.
  6. Connect together all your Battery Power leads (Pin 16 from you OBD2, Pins 1, 7 & 8 from DME Plug 1, and Pin 26 from DME Plug 4, and the +12VDC Lead)
  7. [Optional] I put a switch on the line going to the positive DME pins to emulation ignition for use with JMGarage Flasher, but it is not necessary (as seen in schematic)
  8. Connect together all your Chassis ground leads (Pin 4 from you OBD2, Pins 4, 5 & 6 from DME Plug 1, and the -12VDC Lead)
  9. Connect together all your K-Line leads (Pin 7 from you OBD2, Pin 3 from DME Plug 1 and Pin 32 from DME Plug 4)
  10. Shrink wrap / tape all of your connections to prevent shorts
Now you have a cable you can use to bench flash your DME! No more fumbling around in the car!

How to use your cable
  1. Plug in your power supply or connect battery (12VDC Leads)
  2. Plug your DME into the harness you built
  3. Connect your configured K-DCAN Cable to your PC
  4. Plug your K-DCAN Cable into your bench harness
  5. If you put in a switch, turn it on to emulate switching on the ignition. Without it, the DME will behave as if the ignition is on all the time
  6. Use Galleto, JMGarage Flasher, or Chipster MSS5x Flasher as you normally would

Wiring Schematic


Additional Resources / Troubleshooting


Notes!!!
  • As always, I am not liable if you mess up your DME using this guide. Please take precaution to avoid screwing things up.
  • PLEASE, for the love of god, use a RELIABLE Power Supply with enough amperage to power the DME. (See “What you will need”) If your PSU fails during a flash you could very easily end up with a bricked DME. This is more important than even the quality of your solder/crimp joints.
  • It’s helpful to flash a DME from the Junkers for your tuning purposes. Any Siemens MS43 ECU works, part numbers don’t really matter. This way you’ll have a “known good” DME with stock firmware is you mess up.
  • If your are just tuning your DME you DO NOT have to put your ECU into boot mode. Opening up your DME increases your risk on bricking (destroying) your DME. Only open your DME any put it in boot mode when using JMGarage Flasher.
What is a good Amperage?
 

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1 Amp should be more than enough. Using a higher amperage won't hurt
Thank you,

I ordered a completed wire for dme/ecu flashing bmws of several models (ms42, ms54, etc..) on ebay that is missing just the kdcan and PSU.
It just arrived.
In their instructions paper it recommends not going over 5 amps and keeping between 12.8-14 voltz.
This may be specific to their cable concoction.

But it may be something for others to be cautious and look into for their specific set up, before going over that amount.

I believe installing a fuse on the positive wouldn't be a bad idea as an additional fail-safe.
 

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Has anyone completed this process with a ms54 dme/ecu?

I have an entire spare immobilizer set (Ecu/dme, tumbler sets, ews) that are a ms43 unit from a 03 bmw.

Mine was originally a 2004 with a ms45 ( the original ecu inside the car).

I also have an additional ms45 dme to test this process on (so the original dme doesn't corrupt without backup).

I currently have the new (set bought) tumbler set installed on the vehicle (03 tumbler set with ms43 dme).

I believe the wiring harness is damaged not sending signals to/from ews connector. This means the synchronizing between the dme, ews, and gm5 is impossible no matter what I do. FOB key functions dont work, and no signals to any ews connected. Meaning there is issues from within the car that attach to the ews. I'm certain because i have programmed two additional ews systems using ak90+ to test as a clone and the issue persisted. Also over half a dozen k+dcan cables connected with different software that could not read a signal to the ews. Even the local bmw Specialist shop couldn't synchronize it via obd port. Fuses and relays were fine.

I intend on flashing the ms45 spare dme with ews delete, programming to the original vin.

Since the ews delete should ignore the ews specs, I assume having the ms45 flashed with original vin and either ews should work without worrying about synchronizing?

Let me know your thoughts.
 
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