Odd thing happened

[steveTS]

I have a 2021 Tradesman 2500. It has a 5th wheel trailer hitch for my 39 ft grand design. The problem is when I hook up trailer the drive it then disconnect the trailer without turning off engine I get a check engine light on dash. The engine runs ruff but not horrible. I found that if I shut off engine then restart the dummy light goes off and all seems fine. Is this a a problem I need to address at dealership or just roll with it? Seems like a software glitch

 

[crash68]

The problem is when I hook up trailer the drive it then disconnect the trailer without turning off engine I get a check engine light on dash.

Are you sure it's not the trailer disconnect warning, what you described is exactly what causes that red light in the dash.
This is what it looks like:

The light is supposed to stay on unless the trailer brakes are plugged back in and working or the vehicle is turned off.

Not sure why the truck would run any different when the trailer is disconnected though.

 

[steveTS]

No this is a yellow warning light but the truck doesn't idle normally when it happens. It's odd for sure

 

[crash68]

Probably the best bet is to have the dealership scan the truck for codes, even though the light goes off it should store the fault code.
If they can't read anything you might have to tow the trailer to the dealership and disconnect to get the light to turn on for them.

 

[Timsdually]

Buy a test plug to check the trailer plug.
Plug it in and unplug it and see if it does it with the test plug.
Technically I would think it would. Then you don't have to haul your RV to the dealer to show them.
If it doesn't do it, then something is up with your RV plug.

 

[JPT]

Any chance it is a bad battery? Maybe a bad cell? I wonder if it is something with the charging system, that does something wired once you disconnect the electric load.