Ok, here's the story with my 05 525i:

Changed the oil, started the car to check for leaks, it runs great, everything's fine. I turn the car off, and go to reset the service interval through the trip duration button. I held the button too long and it went in to the german text with the codes. I pushed the button a couple times while in there. Then turned key back to Off to try again. Turned the key back to On and everything goes absolutely haywire. Get multiple error icons, probably every error it has - transmission, window, car movement, ABS, etc. THe gear indicator starts indicating Neutral and then Park and then back again..., and the interior light starts flashing. Try to actually start the car, and it turns over once or twice, then click click then nothing. Eventually all lights go out. During this sequence the iDrive screen is dark and inaccessible.

Try the key again a couple times, get the same thing. Still no iDrive either.

I then disconnect negative batt. cable and let it sit for a while, see if it resets or anything. I reconnect, put key back in. Actually seems like it could be fixed - with the key in the first position, the air system starts up like normal, iDrive comes on, all looks good. Then I turn the key to the On position and everything falls to pieces. Won't start, electronics gone crazy like before.

Any thoughts or suggestions?? Possible ideas:

1) Will be replacing battery tonight, initial thought is perhaps I drained the battery down by turning the car on for short periods of time.

2) I saw forum posts with similar symptoms suggest replacing ISM. Could I have fried it by pushing the reset button incorrectly or something?

3) Possible I cleared the computer programming accidentally, requiring a reprogram? Is that even possible through the button menu?

Just a little surprising I could have done this kind of damage through accessible electronic menu.... Any help or suggestions would be really great. Thanks

 

Do you have any diagnostic tools? Do you know how to use INPA? If you have the BMW standard tools use NCSexpert and code the car back to default. if you don't have them go to BMWcoding.com do some reading and get started. Or, you could just go to the dealer.

 

I believe its 'Battery', how old is your battery?, I would start with changing the battery first.

 

This is just a wild guess, but maybe while you were in the "german" menu, you initiated the "Instrument Panel Test" This is option 02 in the hidden OBC menu (see attached document) and you said pushed the button a couple of extra times once in the "german" menu. This will likely test all the dash warning lights, giving you the displays you saw.

Then maybe your battery power dropped enough during this test to cause the "computer" to malfunction and not return to a stable state. Or maybe you shut off power in the middle of this test, and this messed up the computer leaving you in the mess you are in now.

But, rather than replacing the battery, you might be able to put a charger on the terminals under the hood, giving you a good source of power. Then re-run the programming step with the ODO Reset button. At least, something to try without spending a lot of $$$ on a new battery.

 

Thanks for the suggestions guys. Changed out the battery and it fixed it. I wasn't able to access a charger on short notice. I really should get a voltmeter at very least.

We got the car in 2007 used, and the same battery has been in there since then, discovered someone put a AAA brand battery in there. Everything back to normal now, except for one error message which I'll post separately about. Interior lighting and headlights were actually dimmed for some time but wasn't noticeable until a new battery was in there, now bright and crisp. I went with the Duralast Gold 94R-DLG. Still looking in to whether I need to register etc. even though it's rated the same as the one I took out.

 

Part of the battery registration is entering when the "new" battery was put in. That way the system will know if it's charging an old or new battery along with the spec of the battery.

 

In case anyone else has this happen, I had two error codes when things came back to life with the new battery - P0700 and P1721 CAN timeout. I cleared them and they haven't come back.

 

This is not a battery or anything else. When you held the button too long you went into the hidden menu in german and you pressed the wrong thing. Therefore you need to re encode the car back to default otherwise you will be stuck. INPA cannot do this for you but NCS can. So you will need NCS, a good cable and probably some good daten files to communicate with the car. Sure you can find NCS online but a lot of it is BS garbage. I have a spare cable (Original BMW not a cheap knockoff BS cable) I'd be willing to sell to you though but if you want software you're on your own. It's awesome but I upgraded to another cable because I need to work on ALL bmw's through various programs. If you're interested let me know.
Again, this has nothing to do with your battery. You screwed up the encoding on your car. Take it to dealer and they'll charge you $300 just to put it back. Not worth it.

 

After replacing the battery, the car is happy, all is good so far. Will write up more if problems return. Many thanks for the suggestion.

 

So i assume disconnecting the battery and putting it back fixed the issue. Didn't you already try that? So your issue wasn't anything besides a dead battery? And this happened via the instrument cluster? Sorry, something seems off here.