Airbag ECU replacement

[Spirit Force]

Just an FYI - in case the "internal ECU error" is a result of you messing with module coding using NCSExpert, and you have an MRSZ unit (P/N 8374799), there is a way to reanimate it with software. link.

This is totally different error, which isin't caused by messing with the NCS Expert. This is well known failure for this module. It seems to be affecting modules that p/n end with 6900727.

[jamesdc4]

Thank you for taking the time to contribute, SF.

[bcain79]

I just used this DIY today, worked great. Except my airbag light is on, I am assuming I need to take the car in and have the module coded to my car.

[treat44]

Just did this DIY on my E39 - 2000 528i. It was very simple. I spent last weekend reading, re-reading, and re-re-reading instructions/advice from this forum to properly set up the SW on my laptop. It took me a while, but I'm glad that I took the time. Used these links (primarily): http://www.bimmerfest.com/forums/sho...d.php?t=564570 http://forums.bimmerforums.com/forum...4-step-by-step Bought cables for coding from Amazon. These worked for me: http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 Found a used ECU on ebay for $70. Seller in CA - very prompt and free shipping. The replacement ECU that I bought has the exact same part number and SW version as the one that went south in my car. After installing the replacement, I only had to clear error memory with INPA, no need to re-code with DIS. Yes - you should have included it Getting that connector off was the most difficult part of the whole process. I finally fashioned a tool using a paper clip, gaff tape and a tent stake to get it loose. McGyver would be proud! Thanks for the info you posted hear - it was a BIG help!

When buying a used module, what are the important numbers to match? Obviously pn, but also do I need to find a V2.5 as I have from factory? Will other V numbers work with proper coding as long as pn is same? I'm dealing with the 6900 727. I do not currently have coding experience although it seems as if all I need are proper cables a laptop and some free downloads? If I find correct V2.5 module will I need to code? I can find same V2.5 module but the serial number or Temec Nr does not match my original.

[greasemonkey918]

good write up!

[LinGG]

hey guys I got MRSZ3 which is 65776900727 part number, my question is: will MRSZ4 (pn 65776919789 ) fit my car? I mean.. what ECU module is more reliable (if MRS 4 will fit). Just don't want to see airbag light again. thanks in advance

[av8r4aa]

Can these modules be rebuilt like say, Module Masters?
They did a great job on my ABS module?

[Spirit Force]

I'd personally just replace the module. It's quite easy and cheap to DIY.

[jspeagle]

I'd personally just replace the module. It's quite easy and cheap to DIY.

I've purchased 4 modules in the last year on fleabay for twenty to thirty. That's why no one rebuilds them. The price for a used Airbag module is a quarter of that for the ABS module. I just use the same part number and it's hit or miss after that whether it will code with NCS. The most difficult part, aside from getting a coding setup, is the wide connector--the kind that usually requires a firm grip and some working it to remove. It faces sideways and there's no space for a hand, or even a finger. I can see why BMW recommends removing the console. I tried prying on one side with a large screwdriver, and I ended up breaking the plastic part of the connector while removing it with pliers. Luckily it still works. Maybe I should have soaked it in something. If you are replacing the module due to water in the rear carpet and/or sloshing sounds in the cabin, due to blockage of the drain tubes from the AC condenser, that connector seems likely to have enough corrosion to make it hard to remove.

[MarkHatcher]

Hi there, my first post here and first DIY on the E39, so Hi!: replacing the airbag ECU.

Thanks go to Spirit Force for this thread; I wouldn't have been able to do this job without it. Internet is great.

It took me three hours this afternoon, but it's done. If you think getting the third nut out at the back is hard just wait until you try to remove the connector to the ECU! This is what took all the time for me. How to do this needs elaboration for novices like me, who have never seen any of it before.

I know a picture paints a thousand words....but...When you look carefully at the green locking device as it is installed with the old ECU in place, there is a small tab in the middle of it. This stops you (or the car) just shaking itself free. This tab needs to be pressed down (think long and thin screwdriver), it does so quite easily, so that the whole green assembly will be able to rotate towards you and release (and in fact pull out) the connector. Once you've got the locking tab pushed in, you'll need another tool to get behind the back of the green flap in order to pull it towards you. This then levers the connector out of the ECU. Good news: Once you have the tab pushed in and can get a tool in to pull the green flap towards you, it's easy. However, access is appalling, but I managed it by using a thin hollow metal tube with a paper clip pushed inside it. I had to bend and trim the paperclip to be able to hook onto the back of the green bit. The mechanical force to pull the locking mechanism towards you, AS LONG AS THE TAB IS PRESSED IN, is negligible. Installing the new unit took a minute or two, even for a novice.

Hope this helps....

Mark

[Spirit Force]

Hi there, my first post here and first DIY on the E39, so Hi!: replacing the airbag ECU.

Thanks go to Spirit Force for this thread; I wouldn't have been able to do this job without it. Internet is great.

Nice to hear that you found this DIY usefull.

It took me three hours this afternoon, but it's done. If you think getting the third nut out at the back is hard just wait until you try to remove the connector to the ECU! This is what took all the time for me. How to do this needs elaboration for novices like me, who have never seen any of it before.

I know a picture paints a thousand words....but...When you look carefully at the green locking device as it is installed with the old ECU in place, there is a small tab in the middle of it. This stops you (or the car) just shaking itself free. This tab needs to be pressed down (think long and thin screwdriver), it does so quite easily, so that the whole green assembly will be able to rotate towards you and release (and in fact pull out) the connector. Once you've got the locking tab pushed in, you'll need another tool to get behind the back of the green flap in order to pull it towards you. This then levers the connector out of the ECU. Good news: Once you have the tab pushed in and can get a tool in to pull the green flap towards you, it's easy. However, access is appalling, but I managed it by using a thin hollow metal tube with a paper clip pushed inside it. I had to bend and trim the paperclip to be able to hook onto the back of the green bit. The mechanical force to pull the locking mechanism towards you, AS LONG AS THE TAB IS PRESSED IN, is negligible. Installing the new unit took a minute or two, even for a novice.

Hope this helps....

Mark

That is why I said in the DIY:

8. Remove the Airbag ECU connector. This type of connector is used in number of places on your e39. You'll need to pull the green locking clip towards the rear of the car to release it. If you want to practice how to do it you can find similiar connector on Cd-changer, NAV computer etc.

If you don't know how these connectors work, practice on one that is easy to reach. Once you know how it works it's not that hard to remove. When you release the green locking clip the connector slides out.

[Gentil79]

Here's a DIY about airbag control unit replacement. I had the airbag light on in freezing temperatures. With INPA I got the following error: 240 Internal ECU error, which requires the airbag control module to be replaced

11. Code the new Airbag ECU. I did this with NCS Expert. A great how to code with NCS expert can be found here. Download the HOW TO CODE WITH NCS EXPERT.pdf

Hi there, I had exactly the same problem as you, so I'm replacing the airbag ecu with a second hand one, with the exactly same part number.
However, I would like to know more details about the coding with NCS expert.
When exactly do I have to create a coding profile; before I remove the old ecu or after its removed, but before the new one goes in? I assume that the coding will be done when the new one is in.

[Spirit Force]

Hi there, I had exactly the same problem as you, so I'm replacing the airbag ecu with a second hand one, with the exactly same part number.
However, I would like to know more details about the coding with NCS expert.
When exactly do I have to create a coding profile; before I remove the old ecu or after its removed, but before the new one goes in? I assume that the coding will be done when the new one is in.

First check to see what profiles you got installed in your NCS Expert, if you got Expert mode then you got what you need. If you don't have it then you could download Revtor's profile and use that. Assuming you haven't used the NCS before I would advice you to first connect to the car with NCS Expert to make sure it's all working as it should. If you can get the NCS Expert to show the car information you know everything is working. This is just to make sure your NCS Expert is working as it should. If you know it is working as it should you can get to replacing the module. When the replacement module is installed, you just code it to the car. That pdf shows each step on coding. The difference is that you got e39, so instead of CAS you need to select one of the modules shown, for example select EWS. Then select to code individual module, from the list select ABG (which is your airbag module). Then follow the last step in the guide and you are done.

[Gentil79]

First check to see what profiles you got installed in your NCS Expert, if you got Expert mode then you got what you need. If you don't have it then you could download Revtor's profile and use that. Assuming you haven't used the NCS before I would advice you to first connect to the car with NCS Expert to make sure it's all working as it should. If you can get the NCS Expert to show the car information you know everything is working. This is just to make sure your NCS Expert is working as it should. If you know it is working as it should you can get to replacing the module. When the replacement module is installed, you just code it to the car. That pdf shows each step on coding. The difference is that you got e39, so instead of CAS you need to select one of the modules shown, for example select EWS. Then select to code individual module, from the list select ABG (which is your airbag module). Then follow the last step in the guide and you are done.

Thanks for clarifying. Unfortunately, the link you have on your post for the step by step guide doesn't seem to work anymore.
ill give the NCS expert a go and see if it works and I'll report back

[Spirit Force]

Well you can find plenty of different guides how to code with NCS. It's the same process for each module, so you don't need to look for one that is made for airbag module.

[av8r4aa]

My addition to this:
I had also an internal module fault.
I really searched for a near exact replacement. I found one in Sweden. 60 dollars shipped.
I don't have the alphabet soup computer gadgetry you pros have.
And I didn't need it. If you find a close to production module, you might get a plug and play.
That's how mine turned out.

Also...... TAKE OFF NUTS BEFORE YOU TRY TO GET THE CONNECTOR.

just a tiny bit of wiggle room got my finger in there to pop the connector.
I did have to reset my light with the B800. But it's out now.
Thanking all the great guys and gals on this forum!!!!!

[Spirit Force]

My addition to this:
Also...... TAKE OFF NUTS BEFORE YOU TRY TO GET THE CONNECTOR.

just a tiny bit of wiggle room got my finger in there to pop the connector.

If you followed the DIY the nuts are removed in steps 6 & 7 and the connector in step 8.

I re-uploaded the pictures again, hopefully this time for good (current hosting site imgur claim to keep them indefinitely). I wouldn't have noticed it, but OnTheFence sent me a pm. The pictures were once again removed from the previous free hosting site.

[OnTheFence]

Yes - you should have included it Getting that connector off was the most difficult part of the whole process.
I finally fashioned a tool using a paper clip, gaff tape and a tent stake to get it loose. McGyver would be proud!

+100.
That clip was a BITCH.
Took longer than entire rest of the project.
Do not try to use a pick tool. Waste of time.
Once I figured out the best method, it took 2 seconds to unclip.

Here is the best way to do it:
1) Dislodge airbag module from the 3 studs. Angle it so the left side has more clearance. You can angle it enough so you can SEE the entire green clip.
2) You have to use 2 fingers. You use one finger to press down on the yellow retainer notch (left side).
Use a 2nd finger (on the bottom side) of the yellow thing....to slide the green clip toward the back of the car (towards you)
3) Use a pick tool to push the wire harness away (to the left). I got pissed here and just started pushing the module around helter skelter to get clearance to push the harness away from it.

[MrBlah]

some dead links, I have ncsexpert is there a working howto on coding a replacement module?

[infieldg]

hey guys I got MRSZ3 which is 65776900727 part number, my question is: will MRSZ4 (pn 65776919789 ) fit my car? I mean.. what ECU module is more reliable (if MRS 4 will fit). Just don't want to see airbag light again. thanks in advance

Replying to an old post cos this problem is just getting more and more common - I also have a 2000 E39 540 with an internal error 240, initially only below about 8C but eventually warmer.

Things I learnt ;

1. My original is v2.5 MRSZ3/A.
2. A LOT of 65776900727 ecus have the internal error 240 already - I've bought a few off eBay and all were duds til the last one.
3. You can use a higher version number, but when they say "superceded" they mean "we also superceded every other part of the SRS system so unless you replaced them too, you're boned". If you have MRS3Z/A you can't fit MRS4 etc. The MRSZ4 ecu p/no 65776920848 sitting in front of me as I type is V3.6 and is free to a good home
4. Thinking the original problem stems from a dry joint caused by the alloy housing stressing the PCB when it contracts and expands (mine only failed under 8 degrees celcius) I decided I had to (a) buy from a HOT location, and (b) get the HIGHEST version within my ORIGINAL part number, which from what I could see was the v3.0 I bought from California - it worked great!
5. My usb odbc connector (under bonnet) did not detect ignition in INPA so I fixed it with the jump wire. At one point I thought the cable was my problem and bought a prettier one that also didn't show ignition only this time I didn't bother fixing it, and it coded just fine so don't worry if INPA doesn't show a black dot for ignition.
6. I used the standard Expert Mode, not Revtors - probably makes no difference for straight coding, I just figured since I don't want to edit the TRC and upload a MAN I'd go plain vanilla
7. NCSExpert won't run on 64-bit, but happily runs in XP mode. The first cable I bought came with two DVDs and a brilliant installation and "Launcher" app which totally took care of all of that for me.
8. Here's a summary of what little I learnt of part numbers ;

• 65776900727 - mine 1/3/1999 onwards (newest I found was v3.0, which I bought)
• 65776910676 - 1st supercession 1/1/2001 to 26/9/2001, V3.5, I think this is NOT compatible with MRSZ3/A but can't be certain
• 65776920848 - 2nd supercession 29/8/2001 to 12/4/2002 V3.6, got one, can't code it as it's MRSZ4/16SB
• 65776919789 - 3rd supercession 25/2/2002 onwards V3.7, fair bet there's no chance in hell this'll work with my MRSZ3A bags etc either

This is the first DIY I found and you are a life saver, thank you!!!

Geoff
Wellington, New Zealand.

[Walopower]

http://www.bimmerforums.com/forum/sh...5#post29467505

[georgebest]

Replying to an old post cos this problem is just getting more and more common - I also have a 2000 E39 540 with an internal error 240, initially only below about 8C but eventually warmer.

Things I learnt ;

1. My original is v2.5 MRSZ3/A.
2. A LOT of 65776900727 ecus have the internal error 240 already - I've bought a few off eBay and all were duds til the last one.
3. You can use a higher version number, but when they say "superceded" they mean "we also superceded every other part of the SRS system so unless you replaced them too, you're boned". If you have MRS3Z/A you can't fit MRS4 etc. The MRSZ4 ecu p/no 65776920848 sitting in front of me as I type is V3.6 and is free to a good home
4. Thinking the original problem stems from a dry joint caused by the alloy housing stressing the PCB when it contracts and expands (mine only failed under 8 degrees celcius) I decided I had to (a) buy from a HOT location, and (b) get the HIGHEST version within my ORIGINAL part number, which from what I could see was the v3.0 I bought from California - it worked great!
5. My usb odbc connector (under bonnet) did not detect ignition in INPA so I fixed it with the jump wire. At one point I thought the cable was my problem and bought a prettier one that also didn't show ignition only this time I didn't bother fixing it, and it coded just fine so don't worry if INPA doesn't show a black dot for ignition.
6. I used the standard Expert Mode, not Revtors - probably makes no difference for straight coding, I just figured since I don't want to edit the TRC and upload a MAN I'd go plain vanilla
7. NCSExpert won't run on 64-bit, but happily runs in XP mode. The first cable I bought came with two DVDs and a brilliant installation and "Launcher" app which totally took care of all of that for me.
8. Here's a summary of what little I learnt of part numbers ;

• 65776900727 - mine 1/3/1999 onwards (newest I found was v3.0, which I bought)
• 65776910676 - 1st supercession 1/1/2001 to 26/9/2001, V3.5, I think this is NOT compatible with MRSZ3/A but can't be certain
• 65776920848 - 2nd supercession 29/8/2001 to 12/4/2002 V3.6, got one, can't code it as it's MRSZ4/16SB
• 65776919789 - 3rd supercession 25/2/2002 onwards V3.7, fair bet there's no chance in hell this'll work with my MRSZ3A bags etc either

This is the first DIY I found and you are a life saver, thank you!!!

Geoff
Wellington, New Zealand.

This was super helpful, thanks a lot! I've spent three days figuring out what I'm doing wrong when trying to code it with NCS Expert, turned out the one I bought on Ebay had exactly the same problem (internal error 240). Trying to get one with 3.0 software now, there are some on Ebay. Thanks again for tips, Geoff!

[geargrinder]

I've always wondered if you were to open these up and hard-reflash the EEPROM firmware back to stock (would need a known-good to read from...) if you can fix the problem, or, if it indeed is a hardware failure. I have an internal error one down in the basement, I should try it sometime.

[georgebest]

I've always wondered if you were to open these up and hard-reflash the EEPROM firmware back to stock (would need a known-good to read from...) if you can fix the problem, or, if it indeed is a hardware failure. I have an internal error one down in the basement, I should try it sometime.

How would you do that? Would be interesting to try for sure.

[geargrinder]

How would you do that?

In the usual way.