fiztech-code
commented
1 year ago I cannot speak on the specifics of your setup, however as you are able to communicate with ecu and/or combination meter your circuit is correct. All i can recommend is isolate the body module and try to communicate with it directly.
You may be able to use a vag-com device as a transiver
I'm working with a 2001 Toyota Celica cluster, which has two MPX buses, one to/from the engine ECU and one to/from the body ECU. I have used BeanMPX to successfully receive and transmit messages on the engine ECU bus (battery light, oil pressure light, and coolant temp), but I am unable to read anything off of the body ECU bus, however (I think) I can transmit messages. I have a body ECU here to confirm that the body functions (seatbelt warning, door open warning, and fuel level) are in working order, I just cannot see the messages that are transmitted from the body ECU.
As far as I can tell, my circuitry matches your diagrams as I am able to do stuff with the engine ECU bus. Not sure if I'm just missing something though, I'm very new to this BEAN stuff. Thanks!
Toyota's MPX circuit here, MPX+/- on the ECU side are shorted together in the cluster and are not continuous with the body ECU side.