The BATTSCI bus is a two way comms between the BCM/MCM so I'll have to try and capture only what's sent by the units seperately now to help us make more progress . We don't know at present which unit is sending which packets when, and or what the responses are.
The METSCI may be slightly different, as although it may well be two way comms again between the BCM/MCM, looking at the circuit diagram the instrument cluster is listening in and certainly being driven by these signals. I doubt it (the cluster) is transmitting on this bus, in fact the diagram shows what could be an op amp/comparator input driven by the bus. This could just be another RS485 transceiver.
Anyone have a broken cluster they can look inside? What's connected to the METSCI inputs?
Looking at the rs485 driver IC's inside the bcm and mcm it may be possible to try and capture the data the cpu is feeding/recieving to/from them but it won't be easy and I might have to solder some minute contact points onto the chip legs to hook onto!
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