Just bought a 38' Crossroads Crossterrain. It came with an onan 5500 Marquis Gold generator. The generator did not run and the previous owner said it hadn't since she had it although she had no idea why. As it sits, it will crank and fire and run for a split second. Unplug p1-15 and it will crank and run for 3-4 seconds and then shut down. The oil pressure sensor seems to be working properly. It is registering a fault code of 29 which is a high battery voltage fault. Would this keep the generator from running?
onan 5500 Marquis - Won't stay running
- Thread starter achallie
- Start date
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Gary RV_Wizard
Site Team
The Marquis manual says that High DC voltage is >19v, so it probably does shut down to avoid damage to the electronics. First step would be to measure the source voltage and see if it really is high, or if it is a sensing problem instead.
Gary RV_Wizard
Site Team
I agree that a single battery probably isn't producing 19 volts, but neither will a properly wired multi-battery hook-up. But there could be other problems that cause abnormal voltage too, so best to verify. We are only talking a voltmeter measurement across the 12v feed where it connects to the genset. Only takes two minutes. If it's ok, then you know (rather than assume) you should concentrate diagnosis on the genset side rather than elswhere.
Gary RV_Wizard
Site Team
I'm not inclined to find and study your wiring diagram, so perhaps you could explain what P1-15 is for?
Checked voltage both sitting and running ( for the few seconds it does). 12.5 sitting, never drops below 11 while cranking or exceeds 13 while running. p1-15 and p1-20 are part of the ignition circuit and lead to the magnetos. I can't reach the connection on p1-20 because it runs around the back of the engine and is not accessible without pulling the generator out of the RV.
