Generator Shut Down Without Being Told To (Usually Fuel)
The ONAN-36 (Cummins Onan) diesel fault code means: Generator Shut Down Without Being Told To (Usually Fuel). This is a serious severity code.
- Keep running?
- No — shut it down
- DIY difficulty
- moderate
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What Are the Symptoms of ONAN-36?
- The generator stops on its own while running
- Three blinks, then after pressing Stop: three blinks, a pause, six blinks
What Causes ONAN-36? (Most Likely First)
- Not getting fuel: Cummins says code 36 usually means the generator is not getting fuel Very Likely
- Low fuel level, or a clogged fuel filter or hose Likely
Can I Keep Running It with ONAN-36?
No — shut it down. ONAN-36 is rated serious severity. Continuing to run the unit in this state risks further damage — get it looked at before putting it back in service.
Frequently Asked Questions
What does Onan code 36 mean?
Cummins describes 36 as a common service fault: the generator shut down but was not "told" to by the control, which usually means it is not getting fuel.
How do I see code 36?
After three blinks, press Stop once; 36 blinks as three blinks, a pause, then six blinks.
Mechanics Guide Step-by-step diagnosis
How Do You Diagnose ONAN-36?
Check the fuel level first. On many RVs the generator draws from the vehicle's own tank.
Check the fuel filter and hoses, as Cummins' handbook advises for code 36.
The code stops blinking after five minutes (15 minutes on Series HGJAA). To see it again, press Stop three times within five seconds; the last logged fault blinks even if the condition has cleared.
If fuel is not the cause, have a Cummins Onan dealer or service center check it.
Sources 1
This page is built from documented references. Verify against your own service info before repair work.
Which Vehicles Commonly Get ONAN-36?
- Cummins Onan RV generators with a status light on the Start/Stop switch (gasoline, LP and diesel models)
- Not the RV QD 3200, which shows text messages on its display panel
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