My remote does not display any code nor does the fault light come on indicating a problem.
I called Magnum yesterday and went through some checks with them and they couldn't figure it out. They told me to take it to an authorized service center (ASE Supply in Portland, OR). I talked to the tech at ASE who told me it is probably the internal transfer which makes sense.
Problem: Inverter does perform inverting from house batteries.
Inverter will not charge house batteries, pushing the on button for charging does nothing.
Inverter does not pass through 120v shore power when plugged in or 110v when genset is running. No fault codes.
I installed an old ME 2012 that needs repairing also but does just the opposite charges batteries, passes through 120v and 110v power to the coach but does not invert the battery 12v (DC Overload).
To me this is what the OP was describing as his problem and Magnum said to take it to authorized service center.