Cat D400E data link/ ECM problems.

Working on a Cat D400E articulated dump truck. Having wiring / electrical issues with the data link, code 030 248.02 is active. ET will not communicate with the truck now. I did get my laptop to connect once and It's telling me that the power train ECM is "unavailable". Was still getting data from it tho. Going to do all the checks outlined in that codes troubleshooting guide. And now ET won't connect again. How would one determine if an ECM has failed? Only ECM I've ever had to replace was...

Cat D400E data link/ ECM problems.

Cat D400E data link/ ECM problems.