SLC 5/04 Fault

Hi everyone,
Got this fault yesterday. I cleared it and it hasn't come back yet. I understand what the alarm is telling me but my question is: Can a 1747-SN Scanner module or a RIO adapter cause this fault? There are 3 of them in the rack so I just want to know what to include or not include in the troubleshooting.
Thanks!!

It's been quite a few years (maybe 12??) but I had a fault like this and it was related to a remote rack. It was either the adapter module or the back plane on the remote rack - I am having a hard time remembering which one was the fix (hate getting old). I am not 100% positive of the fault, but I think that was it.

I also called Rockwell and they really had no idea other than to start replacing things.

That is what I was afraid of One of those mystery things that take forever to find.