I am trying to reuse steering wheel buttons in my car to control my iphone without dismantling anything. The traditional way to do this would be the CAN bus, but only the diagnostic bus is exposed on the OBD2 Plug, so I would have to get behind the radio to access the CAN bus for infotainment, however there it also a k-line interface exposed in the OBD2 plug which is supposed to be connected to the radio etc (not sure if the steering wheel buttons are connected to this k-line, but lets assume so for now)

I would like to avoid using an ELM327, so i purchased a couple of mc33290d to play around with. Anyone aware of a library I can use for this chip?