Have RV Questions? Ask an RV Mechanic Online.
Hello, my name is Joe
I will assume your coach has a Cummins engine.
I you could respond with all of the fault codes stored in the engines ECM , that could be a big help in troubleshooting direction.
There are a variety of components on the data link that could cause a disruption in communication. Often the fault codes can give some direction in where to focus.
Thanks for the update,
Since it happens most frequently with high engine temps.
Without the fault codes and number of fault counts available, I would suggest focusing on j1939 components and connections in the engine bay.
I will opt out of the question to allow other experts to respond.