I do not know about other brands, but I work as a tech at a john deere dealer. All of our equipment is specific to JD. You have to use a JD designed software program and hardware to connect to JD machines.
Two of the gator utility vehicles have closed loop fuel injection (825i, and RSX850i) and they both have a regular OBD2 port, however obd2 scan tools will not connect to them. The 825i has a car engine/ecm (I-3 engine from the chery qq) and the 850i has a motorcycle engine (piaggio aprilia). I suspect JD had the engine OEM's change the code in the ecm's to where only the JD scan tool/program can connect to them.