Onan 5.5 EFI code 12 help

Mike Hedger · 06-12-2021, 08:55 PM

Does anyone have experience with a code 12 on an Onan (over voltage)? I have looked at the obvious things the plug to the trailer, checked voltage for the few seconds it runs 125-127 then it shuts down. Have replaced the brushes and gen amarteure bearings about 150 hours ago. Checked brush connections they are tight. Changed pre fuel pump filter just because. If I flip the breaker off it might stay running then flip back on when running and it produces no voltage from the output.

Any advice would be great.

06-12-2021, 08:55 PM	#1
Mike Hedger Junior Member Join Date: Jul 2007 Location: Kemah TX Posts: 93 Likes: 0 Liked 1 Time in 1 Post	Onan 5.5 EFI code 12 help Does anyone have experience with a code 12 on an Onan (over voltage)? I have looked at the obvious things the plug to the trailer, checked voltage for the few seconds it runs 125-127 then it shuts down. Have replaced the brushes and gen amarteure bearings about 150 hours ago. Checked brush connections they are tight. Changed pre fuel pump filter just because. If I flip the breaker off it might stay running then flip back on when running and it produces no voltage from the output. Any advice would be great. __________________ Mike Hedger S/C 4646 MPH Racing and Fabrication