I went with Napa 900 CCA 110Ah battery which seems to be pretty good and also registered the battery with Tool32. Checked the alternator reading with engine running and is looking good as well hovering around 14.3V to 15V.

Here is whats happening, as soon as I turn on the ignition, in a few seconds it starts with 4x4 warning and then followed by the sequence mentioning above. If I start the car and put it in reverse or drive, it moves for like a 15-30s and then stops the car with no lights on gear level and idrive turned off and no climate controls. For it comeback I have to recycle the ignition sequence and then its the same 15-30s sequence.

 

This is turning out to be a bigger problem than just a bad/old battery issue. Today, after installing a brand new high capacity battery yesterday, the battery is completely drained to the point that even the interior lights cant turn on and the idrive has dreaded 'Increased Battery Discharge' message as well. Completely stomped. Checking error messages in Inpa doesn't help as it throws out all error messages similar to the list shown in first post.

For now, I unplugged the negative terminal and kept the battery on charger and my DMM is showing 11.85V while charging, here is something I observed, when I plugged in the charger at the terminals under the hood, it just stuck at showing ~6.35V leading me to beleive there must be some kind of short or heavy drain somewhere.

Does a bad transmission or transfer box does this tot he battery??

I know my transmission is not at its best for the past couple of years, but looks like I should look past that issue. As a next step, I am thinking of replacing CIC with stock CCC unit for now. Meanwhile if you guys have any leads/suggestions please let me know. Tomorrow, will take out all the underpanels to get access to the connectors underneath.

 

Ok, I guess I am going ahead to dive into diagnosing the issue for high battery drain.

From what I read on here, two main reasons that came up are IBS and CAS module linked to one of the door locks. Most of the posts that highlight door locks with CAS option, are all identified by a dealer.

My first question, How to properly diagnose faulty IBS?
Secondly, how to identify fault with CAS module?

I have the DIY software that I can use to check anything that you guys would ask for including ISTA-P

 

Unplug the IBS.
Also make sure the car is coded for the new 110Ah battery. (This won't "fix" anything, but is the best way to keep the new battery healthy).

 

Thanks Josh.

Quick Update:
I kept the battery on a 7.2A Noco charger (unplugging the car ground cable, but leaving the positive terminal connected) on Sunday night and it was still not 100% by the time I came back home from work yesterday while kept showing that it is reaching 100% and is kept showing the same thing when I went to work in the morning.
Unplugged the charger after I came home from work, connected car's negative terminal, made sure all five doors are closed properly and none of the interior lights are on and I dont have anything connected to power outlets anyways. Connected a voltage meter to the battery and kept it on continuous display. Started off at 12.76V and today morning it is at 11.44V

As a next test for today, will unplug the car's both +ve and -ve terminal again and put the battery on charger (dont want to run it dead again), if it still keeps charging by the time I am back home from work, I guess will take it back to Napa, sounds reasonable thing to do??? If it did charge 100% and the charger turns off itself as it should do, will unplug IBS tonight and leave battery connected to the car and monitor the voltage.

Will report back tomorrow morning.

 

You obviously have a parasitic drain somewhere. Just keep isolating things until you find it.

 

Looks like the new battery is a lemon. I kept it on charger for the whole day yesterday and it never went past 50% on my Noco 7.2A, then switched to a Schumacher smart charger (set it to 2A), in about 5min it quickly went up to show battery percentage to 100%, left the for the night and it never went to charged status, but rather stayed in charging mode only.

Not sure what other ways I can try to test this battery other than getting a battery tester and/or taking it back for testing.

 

Take it back.

 

Do you have another battery to test your noco on? I would think if it showed over 12v on one charger and then went to 11v there's a draw in the system. Have you test to see if there's a draw on the system? Does the car go to sleep? You can test the last two before deeming it the battery

 

Looks like its not the battery, checked with a battery tester as well and it showed as good battery. Now, the hunt begins, plugged in the battery, unplugged IBS cable from negative terminal, left the car for over 8hrs, battery voltage dropped 1V from 12.65V to 11.44V. At this point, would like to summarize before digging deep.

- The only upgrade I did was doing CIC and CID upgrade (couple of years ago)
Symptoms
1) As soon as I turn on the ignition, no engine run, 4x4 followed by DSC followed by transmission failure shows up
2) On iDrive, it shows upto 4 messages
- Increased battery discharge
- 4x4 AWD malfunction, a restart may resolve this problem, if the problem persists, have it checked with a BMW dealer
- DSC malfunction
- Start assistance may not be available
- Transmission Failure
3) If I go a head and start the engine, within 10s, it shuts off all electronics, but the engine keeps running. Nothing works, no gear changes or lights, no climate controls, no ceiling stack controls, no door locks, no mirror controls, no headlights and non functional headlights switch as well, nothing on the dashboard works except for the rpm gauge and emergency flashers switch.

Now my two questions,
1) Does a transmission failure cause the issues in step 3 above, except maybe for non functional gear change
2) Is there a systematic way to track down the drain rather than randomly unhooking and wait for the miracle to happen at some point
3) I read over here somewhere that dealers can isolate the issue overnight, but it didnt explain any process. I am guessing it involves some expensive equipment, cant this be done with so many DIY softwares available for BMW?

thanks for any of your suggestions