To chime in (I'm not the original commenter you're replying to), in theory someone could develop an Internet-connected gadget, break into your car without being detected, plug said gadget in, and then drive you into a wall or off a cliff, maybe that's what the grandfather poster is worried about.
But in reality, no one's develop that sort of tech, and if a baddie wants to kidnap or kill, they'd probably spend their resources somewhere rather than hacking such a tool.
> Internet-connected gadget, break into your car without being detected, plug said gadget in, and then drive you into a wall or off a cliff
If someone wanted to make you drive off a cliff, they don't need a fancy internet-connected gadget. They could just loosen some screws on your steering column and leave.
If you have physical access to something you can always compromise it.
Not when it requires physical wires. This isn't some wireless TCP/IP stack connected to the internet.
Car entertainment/air conditioning systems usually also use a physically separate CAN bus so internet-connected dashboard devices don't get access to the engine and steering controls. They may share 12V power and that's it.
Comma.ai gets access to the "secret" CAN bus that can control steering via the lane keep camera next to the rear view mirror, not the OBD port or entertainment system.