12V battery - DC charging hardware fault (?)

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New member
May 14, 2019
My 2014 i3 REX died in my garage 2 weeks ago, the 12V battery failed (I bought the i3 used in 2018, and the battery in it was still the original one, so it "survived" for almost 8 years).

I ordered a BMW one directly from Europe as it would have taken too much for the US shipping and no Remy batteries were available here in the EU. It came with a good charge in it so even if it was built in 2015, I guess it didn't sit discharged for all those years.

I swapped in the new one after having fully charged it.
The car then slowly "booted up" after the long pause, but it was full of errors and faults after (I've read that it's common for the computer to go "nuts" after long periods without the 12V).
Now here comes the problem: among the faults it gave out a "battery unable to be charged" error with the 12V battery logo showing.
I then charged the main battery, and tried again to turn it on, and it still showed the 12v battery charging unavailability. I even tried to drive it around the parking lot and nothing, basically it was letting itself discharge without even trying to charge it. Then 4 days later the battery died.

This morning I finally tried to erase the errors and register the new battery with bimmerlink, but unfortunately, the problem was bigger than the dead battery itself. After starting the car the "cannot charge 12V" persisted, so I checked the errors back with bimmerlink. And found these 2 errors out.


The first error is the culprit, guess component protection means a blown fuse in the DCDC 12V charger.

Guess it was caused by the old dead battery, the car tried to forcefully charge it at all times, trying to keep it alive, but at some point the fuse must have blown.

I looked the error 222240 up on BMW fault codes https://bmwfault.codes/XMLDiagView?doc=MgAwADAAMAAwADEANwA3ADkAMwA4ADkAMQA3ADAANAA=
That's extremely bad news because it's a component inside the EME, and from what I can understand the only thing that they can do is to directly replace the EME, which costs a fortune.
If it's just a fuse wouldn't it be wiser to just try to open the EME and replace it. Or at least try to get a third party technician to see if he can do anything with it. In the worst case scenario, if I opened the EME and didn't manage to repair anything, would BMW still try to repair it, or would they deny the repair since they'd see the EME was tampered with? In that case my i3 would become an extremely heavy paper weight.

Could it be possible that the new battery is somehow faulty and the DCDC charger still can't charge it and gives out that fault even if the EME isn't actually broken?

Got any suggestions? I'm quite desperate cause that EME replacement by bmw is scary expensive.
I paused when I read that your "new" battery was manufactured in 2015. I would definitely want a replacement because that's very old. How likely is it that someone would have charged it regularly? I suspect that it completely discharged at some point and isn't working correctly.

I would be very surprised if the very expensive EME could fail due to a bad 12 V battery.
The symptoms you describe are very similar to the ones that other owners report when the 12v eventually dies a tragic death and appears to take the rest of the car with it.

GENERALLY, the "solution" has been to plug in the charger and then let the car sit overnight or for 24hrs to let the computers talk to each other and "work it out" I've read of many "miracles" regarding this type of issue over the last couple years that were resolved this way.
Yeah, before spending any money on something else, you might want to consider a new new 12v battery to see if that helps. It would be much cheaper than probably any of the other next actions to take.

If you do end up having to go beyond the 12v battery, and depending where you are located, it might be worth reaching out to these folks to see if they can help: https://electrifiedgarage.com/