I have an Onan 5500 in my 2014 Fleetwood Bounder. Generator ran fine all week at Daytona 500 (happy for that) but would not run on the way home or should I say provide electricity to coach. I know code 45 is related to speed sensor but is there anything I should check as a DYI? Rather not drive an hour to the closest Cummins service shop.
So which is it - does it not run, or it runs and won't provide power? On an Onan 5500 generator, error code 45 indicates a "Speed Sense Fault," which usually means there's a problem with the generator's ability to accurately detect its rotational speed, potentially caused by issues with the generator windings, wire connections, slip ring corrosion, or excessive load on the generator itself. So, it could be lots of things. Have you tried running it without a load? Is the breaker tripped on the genset itself? Fuse blown? Seems odd that it ran fine and then it won't while moving. Makes me think of a loose wire.
It will stay on with a continuous blinking light and now power. Yes it has been run with no load, breaker is not tripped. Yes seems odd to me. Trying to avoid a visit to the local Cummins repair shop an hour away. Was just trying to see if there were any thing I could check before making that appointment.
Lots of guys on here smarter than me with these things, hopefully someone will chime in. It's 11 years old, totally possible it's starting to crap out. Do you typically exercise it monthly under load to keep the moisture out of the windings? How many hours on it?
Saw this on another forum:
Pull the brush block assembly (2-10mm bolts - EASY access) and inspect the brushes.. should freely move up and down against the springs in the brush holder. Check slip rings that the brushes ride against. Should be clear copper in color - dark black means they need cleaned. (very common - can be repaired while unit is in the coach)
With the brush block out, push START momentarily and make sure the slip rings are spinning with the engine. If not, either broken belt or frozen/seized tensioner. (common - requires removing genset from coach)
If the brushes are ok, slip rings are ok and the rotor/slip rings are turning true with the engine cranking, then it could be a shorted stator. The speed sense circuit is obtained thru the stator and if it's shorted anywhere in the windings it will cause a 45 error. (rare - requires removing genset from coach, separating alternator from engine)
Also, this is a great video showing access to the brush block and inspection. In this case it was broken.
