I did small hack to get this working, I made direct wire from ECU loom to OBD connector.
Few things to note on this:
You can not simply cut the wire from ECU (pin43) if you have IMMO enabled. Even the route ECU - ODB connector - Cluster fails to "authenticate"
You can not simultaneously keep new and existing wire attached OBD connector (pin7) as this causes "echo" on K-line and fails communication.
You can not use Nefmoto flasher via new wire, as cluster or something cuts the communication. Tried it with reading flash.
You need to reduce speed and samples to keep communication running (otherwise clusters or something breaks connection) for me 10 samples @ 19200baud was okay.
Slow init bitbanging can kill the engine on idle
so give it bit gas when firing up
For the first 4, i was thinking to maybe create short code to drive relays to switch ECU - OBD communication between original and new wire after engine startup not sure if that would cause problems elsewhere.
For 5th, you can start logging before starting engine or bit gas at start of logging.
This works for now, but needs attention when time permits.
Lauri