Generator shuts down; Code 45 displayed, indicating low fuel level (if equipped with a level sensor).

Safety first: Disable auto-start. Handle fuel in a well-ventilated area away from ignition sources.

• Verify fuel level: Physically check the fuel tank level. If low, refill with the correct fuel type (diesel, gasoline, LP) and bleed the system if required.
• Inspect fuel level sensor: Check the sensor mounting on the tank and its wiring harness. Look for corrosion or damage.
• Sensor test: If the tank is adequately filled but Code 45 persists, test the sensor resistance or output per Onan specifications. Replace if out of range.
• Calibration: Some systems require calibration of the level sensor in the controller. Follow the service manual procedure if applicable.