(I wrote OBDII coding for SNAP-ON TOOLS, BALCO 1992-1995).
I must say, finding the shear BULK DETAIL of this thread was hard to follow. I suspect some manufacturers like the obscurity, as a defacto 'copy protection' to protect the product line.
And this VAN and CAN, ...Who or what are they ?
Only kidding there, but assuming that's a standard??? Along with 'MUX', another mystery sounding term.
'MUX' to me as a software engineer, simply means shared system, especially meaning 'shared system data BUS'. But I wouldn't go straight to a hardware schematic, to figure out that protocol.
I believe this sh1#t goes straight to the heart of the 'right to repair' dynamic seen recently.
So, if a person thinks about it, is it a good business model, excluding perfectly competent techs from repair access (i.e. OBD data stream etc)?
I just think it would be fair, taking customer CASH money, to supply non-propriety interface, to car computer. It's running the dang dashboard CLOCK, among other things: that is ridiculous that an owner is locked out, from access to software features.
That said, I did see some very minor things done, such as reversal of bit 7, that sort of oddball mode of use, really only purpose being to lock customer out of access, for repair, curiosity, or whatever (legal) pursuit an auto hobbiest wants to try, on his own car.
Thank you.