[cutlea01]

Sounds like a coms issue on a bus? Bad module dragging it down, maybe? Scope on the various buses to see what's going on. Don't think anyone has ever had issues with corruption on a X260 BCM so there'll be no info on how to fix one.

 

[cutlea01]

Gateway module gone loopy?

 

[cutlea01]

Unplug the 2 fibre cables and use a fibre link bridge on them. No need to remove power each time.

 

[cutlea01]

I'd put an oscilloscope on the MS and HS data buses and see what's going on there. My thinking is a duff module is breaking comms protocols and is transmitting on the bus out of turn so bringing the bus down, then repeat, maybe that's why you sometimes see modules and then lose them to regain them later. Unplug a module at a time, the connector with the twisted copper pairs to remove it from the bus, they're joined to the bus in parallel so very easy to remove by simply unplugging their bus connection.

 

[cutlea01]

Can a bad module on Bring down a whole bus ?

Yes. The bus is 1s and 0s, over the 2 wires. A 1 being transmitted would cause the CAN high wire to show a high voltage (3.5v) and the CAN low wire to show a low voltage (1.5v). A 0 would have both wires at 2.5 volts. A module waits for bus availability before transmitting, but it is possible for modules to talk over each other causing an error, where the module would then send an error frame and retransmit its message. You can do basic measurements using a voltmeter. Any more than basic you need a 'scope to see what's going on, the speed of a MS bus is 125kbit/s and HS is 1Mbit/s (I think, from memory) so you can see visually what's going on.

A handy quick guide to general CAN bus networks:
CAN BUS Troubleshooting Guide