Troubleshooting guide
Onan generator high-altitude derating and fewer appliances
Cummins Onan quick-start and handbook guidance warn that available generator power drops about 3.5 percent per 1000 feet of altitude, so high-elevation trips may require fewer simultaneous appliances.
Use this atlas to identify likely meaning and prepare for service. Shut off power, LP gas, fuel, or water when a listed appliance condition involves flame, gas smell, exhaust, generator shutdown, high temperature, moving jacks/slides, refrigerant, 120 VAC, control boards, repeated ignition failure, or a persistent lockout. Call the appliance maker, RV dealer, or a qualified RV technician for repair.
Owner-safe checklist
- Estimate campsite elevation before blaming a generator fault.
- Reduce load by turning off air conditioning, electric heat, or other heavy appliances one at a time.
- Let the generator stabilize after each load change.
- Call Cummins Onan or qualified generator service if the generator still surges, stalls, or faults under a light load.
Code tables for these appliances
- Cummins Onan QG gasoline generators (HGJAA, HGJAB, HGJBB) 32 codes
- Cummins Onan QG 2800i / 2500i LP inverter generators 29 codes
- Cummins Onan QG 2800 KV generators 4 codes
- Cummins Onan QG 4000 / 3600 LP generators 19 codes
- Cummins Onan QG 7000i dual-fuel inverter generators 25 codes
- Cummins Onan Quiet Diesel 5000-12500 generators 23 codes
- Cummins Onan Quiet Diesel 3200 generators 14 codes