Onan 4 fault code — Generator
Applies to: HGJBB Spec A-B, HGJAA Spec J-K, HGJAB Spec J-L, QG RV generator, HGJAA Spec A-E, HGJAB Spec A-E, HGJAC Spec A-D
What 4 means
The Cummins Onan operator manual lists Code 4 as Over Crank.
Owner-safe checks
- Stop repeated start attempts after the over-crank fault.
- Check fuel level and battery condition from normal owner-accessible indicators.
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 Generator Set for RV Operator Manual A031C171
- Cummins Onan Generator Set for RV Operator Manual A035D009
- Cummins Onan RV Generator Set HGJAA/HGJAB/HGJAC Spec A-E Operator Manual 983-0101