No CAN BUS, but you could link them with ODB-II
ODB-II supports a lot more than reading/resetting diag codes, which is all that most people use it for. You can get info on fuel remaining and tons of other stuff. If you wanted to support that on your phone without your car maker cooperating, someone could develop an ODB II connector with bluetooth that your phone could pair with.
Just leave it plugged in all the time, put a little memory in it so it can record data when your phone isn't present, and you could have access to all your car's data every moment it drives from your phone. And this is something you could do even on a 10 year old car...
Biting the hand that feeds IT
