Onan 1 fault code — Generator
Applies to: QG 2800/2800 EVAP KV Spec E-M, QG 2500 LP KV legacy models
What 1 means
The Cummins Onan QG 2800 KV operator manual says one blink indicates shutdown due to high engine coolant temperature.
Owner-safe checks
- Shut the generator down and let it cool.
- Check only visible cooling-air openings for blockage before calling service if the fault repeats.
Service-only work
- Internal generator electrical, fuel, engine, sensor, controller, and output-voltage diagnosis belongs to Cummins service or a qualified generator technician.
Safety boundary
Generators can produce carbon monoxide, moving-part hazards, fuel hazards, and lethal voltage. Shut the generator down and do not open energized compartments unless qualified.
Official sources
- Cummins Onan RV Generator Manuals
- Cummins Onan QG 2800/2800 EVAP KV Spec E-M Operator Manual 981-0153