Generator will not start and the display shows E05 after several crank attempts.

Safety first: Place the generator in OFF, disconnect AC output via transfer switch, and chock wheels (if applicable). Avoid extended cranking to prevent starter damage.

• Check battery voltage: Using a multimeter, measure across the battery terminals. Voltage should be around 12.6 V (12 V system) at rest. If below 12.0 V, charge the battery or replace it with a Yamaha-approved starting battery.
• Inspect battery connections: Clean any corrosion from terminals and ensure clamps are tight. Check the battery ground cable connection to the frame.
• Listen for starter solenoid: When starting, listen for a click at the starter relay/solenoid. No click may indicate a faulty solenoid, starter relay, or control board output. Replace the defective component.
• Verify fuel supply: Ensure fuel valves are open. For diesel, bleed air from the fuel system using the manual priming pump and bleed screws on the fuel filter and injection pump. For gas, confirm gas pressure at the regulator per Yamaha spec.
• Check ignition (gasoline): Remove a spark plug, inspect for fouling, and test for spark using an inline spark tester. Replace spark plugs and ignition coil if no spark is present.
• After corrections: Clear the E05 code and attempt a start. If the engine still fails to start, further diagnostics of the ECU and sensors by a Yamaha technician is recommended.