I was getting code 38 as well.The generator would start run for a few seconds and shut down.I traced it to a broken ground wire just to the left of the main service access panel. There is a main ground post with many wires tied into it.I replaced the terminal and now it’s good as new.Hope this helps. I am an OTR trucker and relie on my generator.Had to due without until home time to properly diagnose the issue
hope this helps others