Onan generator shutting down after releasing start button

Hi! I have a 2013 class C with an onan 4KY generator (series P). It only has about 200 hours on it. It shut down one day (actually after being on only for about an hour after Hurricane Ian) and then when starting, it turns over great, but shuts down right after releasing the start button.

When I hold the button, I get a four blinking light code.

I disconnected the inside switch with no luck.

The odd thing is that, about 2 months later, I tried starting it, and it started right up and ran (no load) for 5 minutes and I manually shut it off. I tried again a couple of weeks later, and it started right up again.

I tried last week, and back to the issue of shutting down right after releasing the start button.

It is a manual transfer, so I have a 30 amp outlet I plug my RV cord into when I want to use the generator. I checked for AC voltage at this plug and get about 20 VAC.

Any thoughts? I initially thought brushes, but having it start up in between issues seems like it might not be (and also the low hours).

The RV is a bit low on fuel (about 1/4 tank) but I would think that a low fuel situation would not fire the generator to run initially anyway. (Unless there is some sort of electronic fuel sensor on the genset that faults the control board?? - I always thought the fuel pick up was just higher in the tank).

The control board it buried under the start relay, and I haven't tried taking out P1 and looking into that yet.

Any thoughts on accessing the control board on this model? I'm trying not to have to figure out how to get the generator out of the RV and work on it while still mounted.

I don't believe there is any oil sensor (the oil is full - recently changed about 20 run hours ago), but if you believe otherwise, please let me know!!

Thanks in advance for any insights or help.