OBDII has standard info that's the same from one brand to another but it also transfers proprietary info that depends on the reader having the ability to interpret it.

My OBDII Bluetooth dongle lets me get diagnostic codes for much more than emission systems (using Car Scanner app where you choose the type of car you're diagnosing) and it also allows me to reprogram car features with the right app (ex adding an Europe only feature to a Canadian BMW i3 with Bimmercode). It would be perfectly adapted as an EV diagnostic port.