Help onan generator 4000 - serv req 3, over crank 4, crank rapid

[Scubawise]

Hi my brother has onan 4000 coach year 2019
Runs for 30 to 60 minutes and shuts off.
Generator shows service req 3, over crank 4, crank rapid??
Oil looks fine not dirty ..he is changing oil since bought used and changing air filter

[Scubawise]

We are at 3000 altitude and he set to 3250 still goes off

[Scubawise]

Hi brother red codes wrong ..he is doing oil and filter..no blinking lights just goes off