[NIKNAIZ]

BMW E92 335D, 2007.

Hi. I have been suffering from a rare issue that has happened twice this year and I have no clue what causes this. I have two issues, will explain both in detail. I don't know how to reproduce either issue, it's purely random.

First problem:
Sudden electricity loss (total blackout) upon pressing ignition button.

How it happened:
Unlocked the car, got in, turned on ignition (so far so good), all gadgets such as dashcams, ambient lighting, etc, works perfectly, pressed brake and Start button, engine cranked one time and everything just shut down instantly.

While car had no power, I got out of the car and measured the voltage under the hood and it read 3.60V or something (did not measure on battery terminals to compare sadly), which, I think, indicates a short somewhere? I connected the battery charger, charged it for literally 5 minutes and it was back at 12.6V, could start the car as if nothing happened, all accessories work and drove to a gas station, turned the car off. Fueled it up, got in, pressed the Start button, same exact issue. Had to call a friend to jump-start my car and it worked as if nothing happened. This happened twice in one day during summer and I haven't had this issue ever since.



Second problem (most likely caused by the same problem first problem is caused by - I have a video of this issue):
Sometimes a powered on car tends to go through a weird sequence where:

At first, CCC and all center console buttons go offline and completely shut down.

Then, dashboard shows all kinds of critical errors (such as Airbag, Transmission, Battery Terminals, ABS, Stability Control), mostly all error LEDs light up.

After a couple seconds, the dashboard lights gradually go away

This is followed by RPM gauge freezing (pressing gas pedal will rev up the engine and mechanically the engine works perfect at this moment). The RPM gauge won't budge.
Video 1: Can see stuck RPM gauge, errors, CCC off

Now, engine will stutter and car slightly shakes, all while white smoke comes through the exhaust. I was told this also is an electrical problem, which causes injectors to not work properly and unburned fuel.
Video 2: Can see white smoke and hear irregular engine sound

It's like a domino effect. An electrical problem (maybe a short?) that takes out car systems one by one, starting with the most sensitive ones. Restarting the car makes the problem go away.



Details that might help:

I have about 30W worth of gadgets connected to my cigarette plug. They use no more than 30W at best, I've calculated this.

I have a relatively new Varta H3 Silver Dynamic 100Ah car battery.

I have cleaned the battery terminals and the clamps are tight.

I took out the battery to check whether there's water in the battery compartment and there was none. There's only dirt and an orange substance which is not rust. You'll see in the video. My car has had Krown anti-corrosive treatment.

I inspected the two terminals that go through the wall and they are in pristine condition, to my knowledge
Video 1:

Video 2: https://www.youtube.com/shorts/bTw72r3_q3w

ANY help is appreciated. Let me know what steps to take. If you know what the problem might be, I would be thankful for a detailed guide to solve this.

[ptpending]

you have to inspect these battery wall connectors from outside, you have to remove rear wheel and arc cover
also you might need to check the the fusebox connector
this is also well known issue for 2007 and newer e9x