What (sensor?) controls warning notification of things

[zen2u]

First off props to all the gurus out there sharing all their knowledge! Huge resource and a big thx!

2005 X5 4.8is, 72k, So Cal weather only, bought in 07 with 12k miles :

Wondering if there is some electronic sensor or other widget needing replaced due to this:

Now and then (1-2'ish times a month), while driving, the following things happen SIMULTANEOUSLY

1) I get an audible tone (like the seat belt tone) but only 1 audible "bong"
2) Various cluster lights come on. 4x4 light, trans, and others.
3) Power steering seems to get funny.
4) Trans never shifts and the rpm's are high (like 4-5 thou at 50-55 mph if on the highway and I hobble to the next exit going as slow as possible with the tac screaming).

There never seems to be the exact warnings lights each time but hard to tell since when it happens I'm focusing of getting to a safe lane or exit vs. memorizing the cluster. But man, the dash cluster becomes christmas tree lights, bam everywhere lights.

* So I pull over (or red light) turn off engine then turn back on and 90% of the time it all clears. By clear i mean the car now shift and drives fine and I keep driving. The remaining times I've shut it down and later when starting it is gone until its next episode.

I cannot image that so many things go bad at once thus it must be a sensor or something vs. each item's warning indicator meaning multiple failures are happening at once. What are the odds of that?

I am at whits end. Someone just club me at this point. Anyone out there familiar with this first hand or not? My luck with the BMW dealers is such that nothing is worth sharing on that front.