In order for openpilot to be able to control vehicle speed, it needs to access to ignition status, PT-CAN and F-CAN. (F-CAN doesn't need to be connected with VO540 )

Full CAN connections are here. But we don't need it all.

Connection requirement:

It is possible to code in DCC in many

There are many places, but this one is best ;)

PT-CAN and Ignition status are spliced in a big wire-loom in the driver footwell corner above footrest plastic cover.

"Splices" are just wires twisted together and covered with a plastic sleeve. All CANbuses have two splices - CAN Low and CAN High.

We need to add wire to each one of them and route it to the harness.

F-CAN is available as splices exposed in a wire-loom below front of the driver door frame (under footwell floor lining). (This is for LHD car. Verify CANbus placement for RHD)

F-CAN was harder to access as it required popping door step panel and lifting carpet floor a bit while adding a new wires to splice pair.

Comma Harness Box can be used, but also it can be easily DIY'ed using a resistor, jumpers and screw terminals, as currently we don't need switching between the busses (this may change for ACC option). The resistor can be probably between 100-400 ohms.

And finally, BMW CAN mapping is here.

And on the car side is here.