Onan generator · 6 model lines
Onan generator code 1
Most Onan documentation lists 1 as “Engine Over Temperature”. Some model lines word it differently or give it a different meaning: QG 2800i / 2500i LP (HGLAA Spec A-B) (“High Engine Temperature”); QG 7000i DF (HGLCA Spec A) (“Engine Temperature Exceeded Limit”).
Check your model first. The same code can mean different things on different models. Find the model number on the appliance's data label, then use the matching row below.
What code 1 means by model
What you can safely check
- Stop the generator and let it cool.
- Check oil level only with the unit off and cool.
- Check only exterior intake or discharge blockage from normal access points.
- Shut the generator down and let it cool.
- Check only visible cooling-air openings for blockage before calling service if the fault repeats.
- Check only coolant level and exterior air inlet/outlet blockage if the manual allows safe owner access.
- Reduce loads before any safe restart.
Stop and call a technician for
- Internal generator electrical output, inverter, controller, sensors, fuel system, ignition, AC circuit, and engine diagnosis belongs to Cummins service or a qualified generator technician.
- Electrical output, inverter, controller, stator, rotor, fuel injection, sensors, wiring, coolant-system service, fuel leaks, and generator compartment repairs belong to Cummins service or a qualified generator technician.
Generators can produce carbon monoxide, hot surfaces, fuel hazards, moving-part hazards, and lethal voltage. Shut the generator down and do not open energized compartments unless qualified.
Write this down before you call
- generator model/spec letter
- hour meter
- fault blink count
- loads running when the shutdown occurred
Full code tables for these models
Related troubleshooting guides
Official sources
OnanCummins Onan RV Generator ManualsOnanCummins Onan Quiet Diesel 10000/12500 HDKCA/HDKCB Operator Manual A043D713OnanCummins Onan Quiet Diesel 5000 HDKBA Operator Manual 0981-0166OnanCummins Onan Quiet Diesel 6000/7500/8000 HDKAH/HDKAJ/HDKAK Operator Manual A046L053OnanCummins Onan QG 2800i/2500i LP HGLAA Spec A Operator Manual A062Y985OnanCummins Onan QG 2800i/2500i LP HGLAA Spec B Operator Manual A075S349OnanCummins Onan QG 7000i DF HGLCA Spec A Operator Manual A079E225OnanCummins Onan QG 2800/2800 EVAP KV Spec E-M Operator Manual 981-0153