2002 Cummins 480 CE Data Link Inactive Message

Hi everyone, over the weekend I lost my port side engine to a “data link inactive” message displayed on my Cummins display. Engine will now crank and not start. The pcm connectors are clean and tight, the big rectangle serial connector at the back of the engine is clean and tight, that harness has the twisted wires all the way up to the display. I found a reset breaker on the engine that had a broken wire fixed that, that has battery voltage now, still no change. Are there any other spots or connectors on this set up that are common fail spots? I checked the 4 wire flat connector, which has 2 grounds and 2 power wires heading up to the pcm, and they check out. Starting to be at a loss as to where the harness from the engine up to the display is losing data. Or is the display just a repeater displaying a problem originating down at the pcm?