Generator cranks but does not start, then displays E03 on the controller

Safety first: Turn OFF the generator and disconnect the battery negative. Work in a well-ventilated area away from open flames or sparks.

• Verify fuel supply: Check the fuel tank level (for diesel or gasoline models) or the gas supply pressure (for NG/LP models). Ensure any manual fuel shutoff valve near the engine or tank is fully open.
• Inspect fuel filter: Locate the in-line fuel filter on the Honda engine fuel line. If it appears dark, clogged, or has not been changed per schedule, replace it with a genuine Honda-compatible fuel filter.
• Check for air in lines (diesel/LP/NG): After filter replacement or fuel line work, bleed air from the system according to the service manual. This may involve loosening a bleed screw on the injection pump or fuel rail and cranking until fuel flows without bubbles.
• Test electric fuel pump: With the battery reconnected and controller in MANUAL (do not crank), listen for the fuel pump priming sound. If silent, check the fuel pump fuse and relay in the control panel. Replace a blown fuse only after checking for shorts. If power is present but the pump does not run, the pump is likely faulty.
• Attempt restart: After confirming fuel supply and filter condition, try starting again. If E03 persists, further diagnosis of injectors, carburetor (on gasoline models), or fuel solenoid is required and is best handled by a Honda service technician.