I know this is a response to an old message, but I was wondering the same thing and ran across this post. Do you have some kind of car holster, and when you put the phone in it, it activates the Car Mode? I have an LG Revolution, and that's how mine works.
Unfortunately, at least with my phone, there is no way to disable Car Mode through software. However, I found that the holster has a tiny round piece of metal inside the bottom, where it cradles the phone (the front left piece of the cradle), and by using a very small drill bit, I drilled a hole in the front and gently pushed the metal right out. I guess the phone has some kind of sensor inside that detects the metal in the holster and puts the phone into Car Mode. With that piece of metal gone, the phone no longer knows it's in the holster, so it doesn't go into Car Mode. Yay!
I'm rooted and I have Titanium Backup, but I didn't see carhome anywhere in the list. That was the first thing I tried. My solution works, but unfortunately, it is rather permanent.
