Onan 23 fault code — Generator
Applies to: HGJAA Spec A-E, HGJAB Spec A-E, HGJAC Spec A-D
What 23 means
The Cummins Onan HGJAA/HGJAB/HGJAC operator manual lists Code 23 as Low Oil Pressure Cutoff Switch.
Owner-safe checks
- Stop the generator.
- Check engine oil level only after safe shutdown and according to the operator manual.
- Record whether the shutdown occurred during start, warmup, or under load.
Service-only work
- Oil-pressure switch, engine lubrication, wiring, controller, and internal generator 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 RV Generator Set HGJAA/HGJAB/HGJAC Spec A-E Operator Manual 983-0101