So this started happening to me today (or perhaps last night). The car dock automatically started booting up. And note this, I wasn't charging it. I have the original software that came with my phone from day one (nearly a year ago) since I rooted it the day I got it, shit happened, didn't really mess with it...so it has never been updated for about a year.
I've tried the battery pulls, disabling the car panel autolaunch, I've even installed some apps just for root so it would put car panel in a quarantine to never launch, I've tried turning on airplane mode and doing a restart, even did airplane mode doing a battery pull, pulled battery and SD card, cleaned out the phone with canned air....and to no avail, this problem still persists.
I think I have a 1 year warranty on this phone so I'll be taking it in before that expires. Just thought I'd give my $0.02 on what all I've done and what all has failed for me.