Onan 12.5kw issues

[Ed McLawhorn Jr.]

Need help on issues with 12.5kw diesel onan on my toterhome. Purchased toterhome in 2022 and no issues other than running rich (black smoke). Installed vent stack and gen would randomly cut off once or twice a weekend. No issues starting back and runing remainder of weekend. I didnt install stack and left storage door open for a couple races and no issues with cutting off. Recently, it has gotten worse and now cuts off 5-6 times during the weekend regardless of stack installed or storage door opened. This past weekend it was cutting off every couple hours. Most times, this weekend once it cut off, it would only start back after 20-30 minutes. Found code 45 and checked brushes today and they seemed clean. Only issue was one was much shorter than the other....seemed odd. Ordered new replacement brushes, but not confident brushes are the issue. Code 45 also indicates problem could also be pcb board. Assuming worst case, is it possible to change board without going to a onan repair dealer? Has anyone else had experience with code 45? Thanks for any suggestions.

Ed