It's important to note that ALL vehicles running Navistream in the US or Canada have a properly functioning ECM connection. If this is found to not be the case, your Drivers can be placed out of service and/or fined by the DoT/CVSE in contravention of the newly mandated use of ELDs. There are provisions for vehicles that have electronic logging devices (ELD) installed prior to that date as a path to compliance. But, that will run out on Dec 16, 2019 when all Carriers will need to be fully compliant.
So, what should you do if your vehicles don't have an ECM connection, or that connection is bad/intermittent?
The first thing you need to do is be aware if an issue is present. The link below outlines both methods of determining the status of the connection and how to fix issues if they've come up.
Knowing when you're having an issue is important. There are certain things outlined in the document above that you can use to diagnose problems, but drivers can also be on the lookout for "Malfunction" states on their tablets. When a tablet is in Malfunction, it needs to be repaired within a week to avoid penalties.
https://www.fmcsa.dot.gov/faq/what-must-driver-do-if-there-eld-malfunction
Information on what Drivers can look for regarding these special states can be found here: Navistream Tablet Training - Overview
A summary of the possible states and the recommended actions can be found on our Support Site:
http://navistream.stti.ca/en/support/solutions/articles/1000273735-malfunction-and-diagnostic-states