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I've read numerous threads about problems with the Battery Control Module. I've had a year of electrical nightmares and I'm 99% certain I need a replacement A2305401045. I have not yet had a chance to remove the old one but I expect that when I get it out and the cover is removed, the magic black smoke will have been let out of some components. I've contacted my local Mercedes dealer and it appears this part is no longer made and there does not appear to be any stock in the dealer network. There might be some new ones on eBay and then there is always the used options but I really don't want to go with used for such a problematic part.
Has anyone sourced a replacement A2305401045 battery control module in the last year or two? If so, where did you get it from and how much did you pay?
Thanks,
Ryan
Not saying you don't have an issue with the BCM, but it might be related to something else.
If you want to replace the BCM then a used one from a wreckers is the go; just open it up first to check for any visibly burnt components on the board.
Last edited by Tom Manning; 06-17-2023 at 08:55 AM.
Can you explain why they catch fire, instead of spewing your rhetoric and opinions? That would be more helpful than just disregarding the issue. At this point you are of no help. Maybe if you are not concerned, you should just move along and use your battery disconnect.
And BTW here’s the BCM from my 45,000 mile 2004. No battery light or any other issues, just decided to inspect it for issues. It’s also a newer version. So there’s that for your silly reply as well. Maybe your time would be better spent finding out the cause instead of just dismissing it as a fluke , and again spouting your opinion. .
In what way is that not helpful? OP doesn't state the problem - it's their first post - just that they've had electrical issues. In the absence of a new BCM, if that is in fact the OP's issue then a second hand one is good advice. How else would they fix it?
That is a useful opinion. And helpful.
As is disconnecting the battery for those who want extra insurance and don't want to connect a charger. That is also a useful and helpful opinion, and option.
Who dismissed this issue as a fluke? Not me. Without a circuit diagram of that module the cause will be next to impossible to ascertain.
Not saying you don't have an issue with the BCM, but it might be related to something else.
If you want to replace the BCM then a used one from a wreckers is the go; just open it up first to check for any visibly burnt components on the board.
that’s most certainly not what your unedited post said, as that edited post is what you should have written to begin with.
Maybe your time would be better spent finding out the cause instead of just dismissing it as a fluke, and again spouting your opinion.
As mentioned, who dismissed it as a fluke? Not me. That's wrong. There is an element of anxiety around BCM fires, understandably. Those that catch fire get the press but I'll posit that the total number of fires is low.
Those burnt SMD resistors are a worry.
I stand by my opinions - I do all the work on my car myself, read widely and as an electronics technician for 35+ years, know something about the subject.
If you search for one, there are 2 part numbers out there currently:
230-540-10-45
230-540-10-45-80
The "-80" in MB part numbers generally indicates a re-manufactured part vs. a new one.
I suspect in the case of the R230 BCM, however, that because they stopped making new ones awhile ago, the part numbers were just consolidated into one.
This would explain why 230-540-10-45-80 is shown as NLA / Discontinued but 230-540-10-45 is still available.
As far as I can tell, 230-540-10-45 is the latest and greatest. Its predecessor is 230-540-09-45, and given the safety risk, worth to be placed into the preventive maintenance category.
Dunno where they got it, but my indy shop got me a new BCM 2 months ago. If an R230 owner is having gremlins, before looking towards the BCM, I'd ask, how new is the trunk battery? Is it even the right type of battery? If it's failing that would cause a plethora of gremlins. I think if your BCM is going bad there wouldn't be any question about it. My 03 SL55 AMG had a duralast alternator installed by a Previous owner, and when I bought the car the trunk battery was an "ordinary" lead-acid type car battery, not an AGM. Even though this battery was only six months from new, on my second day of ownership I replaced that battery with a nice new $235.00 Duracell AGM, knowing what should be back there. Most of the Benzos I have owned have had wrong, cheap, or incorrect parts installed by inexperienced workers.
There are some very strange items in some of the SAM modules... I'm not sure if the following is in the BCM or the SAM that controls the airbags, but look:
It's very interesting, in that there is a small pyrotechnic device that interrupts power.... permanently...
Dunno where they got it, but my indy shop got me a new BCM 2 months ago. If an R230 owner is having gremlins, before looking towards the BCM, I'd ask, how new is the trunk battery? Is it even the right type of battery? If it's failing that would cause a plethora of gremlins. I think if your BCM is going bad there wouldn't be any question about it. My 03 SL55 AMG had a duralast alternator installed by a Previous owner, and when I bought the car the trunk battery was an "ordinary" lead-acid type car battery, not an AGM. Even though this battery was only six months from new, on my second day of ownership I replaced that battery with a nice new $235.00 Duracell AGM, knowing what should be back there. Most of the Benzos I have owned have had wrong, cheap, or incorrect parts installed by inexperienced workers.
Please view the pictures above to confirm that the BCM can have damage and there are no faults in the car. Fully running, no battery light, fully charging car. This is the newer part version not the older one.
Wow this generated a lot of responses!
My problems started about a year ago shortly after I jump started a neighbour's car. Went out for a drive on a Sunday for a pub lunch and had a low battery alarm - nothing too unusual at this point as I don't drive the car regularly and don't always get it back on the trickle charger.
The alarms got worse and changed to angry red warnings and I realized the problem was serious. We stopped to run an errand and the car would not restart. Got jump leads and could start the car but it would die once the donor battery was disconnected.
It appeared that the alternator was not charging the battery. Got a tow home and recharged both batteries. I was able to confirm that I indeed had an alternator issue. I pulled the passenger foot well apart and confirmed that the fuses there were fine.
I bought a new regulator for the alternator and changed it from under the car. A painful but successful job. The alternator still wasn't charging.
I pulled the alternator out and took it to the local alternator/starter shop. The guy quickly diagnosed that the diode pack was toast. He replaced the diode pback and the bearings and I had a working alternator again.
I went away for the weekend, a two hour drive and the car behaved well. The next day I tried to start the car and the starter battery was dead. Very strange - how could it have drained overnight after a 2 hour drive?
Charged it overnight and it started OK and I got back home without further drama.
Since then I have been disconnecting the starter battery and keeping the consumer battery on trickle charge.
The other week I got my amp clamp out to see if there was any parasitic load on the starter battery - nothing. I measured the battery voltage for a couple days and it was holding as it should. So it remains a mystery why I had a flat starter battery.
The last couple of times I took the car out I had a red battery warning light even though the car was otherwise behaving ok. I have a basic diagnostic scanner and it is currently not finding the BCM on the network. That is what led me to believe that the BCM is toast.
Yesterday I pulled the boot apart and got access to the BCM. I took the cover off of it and the board looks pristine. No sign of any burnt components.
So I'm not sure what to do next. No obvious BCM failure but something is still wrong. I think I will take the car to my local MB specialist, he has an R230 himself, and see if the real MB diagnostic tool can provide any additional information.
There are two BCMs left in the UK dealer network, about £1800 incl VAT. One or more new ones on eBay for £1500 and an assortment of used ones. I just don't know how much to trust a used one.
(I'm in the UK near London and both batteries are original MB less than 2 years old.)
One day I will have a dependable fault free car again....
First thing - did you jump the car from the front or rear battery? As you have no doubt read by now, never use the rear battery.
Is your basic scanner MB specific? It's more or less essential (or at least good economics) to have your own MB specific scanner, as they're powerful and not expensive now. Check out the Launch CReader Elite. Once you have used it a couple of times it will pay for itself. And you will need it again...
Is the starter battery charging? Check it comes up to around 14 Volts. If it is not charging then you may well have a BCM issue.
The red battery light seems to have a life of its own and a generic scanner won't clear it. Different faults can cause the red warning - even the rear battery voltage dropping below threshold.
Hope that helps and let's see others' insights. Those BCMs sure are pricey, and you can't get them at all down here now. I sure wish I could get a circuit diagram of that module.
Thanks Tom,
I confirm that I jump-started from the front only. (I've owned the car for ~8 years now) I have however been connecting/disconnecting the starter with the consumer still attached which according to the manual I should not be doing, I haven't figured out the logic behind it though.
Here is the scanner I bought, cheap and basic but it is MB specific:
It looks fairly comparable to the one you suggested.
The last I checked the starter battery was being charged though I ought to recheck it. I've done a few short drives (10-15 starts) and there is no sign of difficulty in starting.
I think my best plan is to go see my specialist, hopefully I can go this week and take a step forward.
An update - on the weekend I took the next step. I disconnected the multi-pin connector from the module. The contacts looked good. I then reseated the connector and reconnected the 2 batteries. The car started without any trouble and no Angry Red Warning about the electrical system. The scanner was now able to see the module again and there were errors about it having lost Canbus contact with its neighbour. I was able to erase the stored codes and the module was fault free. I will keep an eye on things for a while but it is possible that it was just a bad connection that was resolved by reseating the connector. Fingers crossed that is all it is and I will be back to trouble free motoring.
An update - on the weekend I took the next step. I disconnected the multi-pin connector from the module. The contacts looked good. I then reseated the connected and reconnected the 2 batteries. The car started without any trouble and no Angry Red Warning about the electrical system. The scanner was no able to see the module again and there were errors about it having lost Canbus contact with its neighbour. I was able to erase the stored codes and the module was fault free. I will keep an eye on things for a while but it is possible that it was just a bad connection that was resolved by reseating the connector. Fingers crossed that is all it is and I will be back to trouble free motoring.
Sometimes the simplest solution is the correct solution. Congratulations and good luck that you fixed it.
Good result. I can't count the number of times I've 'fixed' equipment by removing and replacing connectors, or rocking PCBs in their slots. Always smart to use a bit of DeoxIT on reassembly.
I've had about 3 years of electrical nightmares and now the Battery Control Module died. I was being quoted around $500 for the part, but it's been discontinued and refurbished is the only way to go now. Refurbished or Used is at about $1000. These cars really have been crappy with their electrical systems and two batteries.
Originally Posted by rjshook
I've read numerous threads about problems with the Battery Control Module. I've had a year of electrical nightmares and I'm 99% certain I need a replacement A2305401045. I have not yet had a chance to remove the old one but I expect that when I get it out and the cover is removed, the magic black smoke will have been let out of some components. I've contacted my local Mercedes dealer and it appears this part is no longer made and there does not appear to be any stock in the dealer network. There might be some new ones on eBay and then there is always the used options but I really don't want to go with used for such a problematic part.
Has anyone sourced a replacement A2305401045 battery control module in the last year or two? If so, where did you get it from and how much did you pay?
Thanks,
Ryan
I've had about 3 years of electrical nightmares and now the Battery Control Module died. I was being quoted around $500 for the part, but it's been discontinued and refurbished is the only way to go now. Refurbished or Used is at about $1000. These cars really have been crappy with their electrical systems and two batteries.
What evidence do you have that the BCM actually died? Has the trunk/boot been pulled apart to access it? Has the cover been removed from the module? How does the circuit card look?
I thought my BCM was dead and I was ready to replace it after a year of electrical nightmares but in the end it was a bad connection and removing and reseating the multipin connector was all that was required.
I wish you good luck finding a resolution one way or the other, it is a real down on the fun of this car.
I was going to refurbish it with a company called ProgRama, but they instructed me to open and it up. On the outside it looked okay, but it was burnt completely on the inside. It could not be saved. I thought it was going for $1000, they are almost at $3,000 online used and or refurbished.
Originally Posted by rjshook
What evidence do you have that the BCM actually died? Has the trunk/boot been pulled apart to access it? Has the cover been removed from the module? How does the circuit card look?
I thought my BCM was dead and I was ready to replace it after a year of electrical nightmares but in the end it was a bad connection and removing and reseating the multipin connector was all that was required.
I wish you good luck finding a resolution one way or the other, it is a real down on the fun of this car.
06-16-2023, 06:37 AM
