Generator shuts down and displays E05, often under heavy load

Safety first: Disconnect non-essential loads from the transfer switch or load center before working on the generator. Turn the generator OFF and disconnect battery negative.

• Reduce load: Confirm that the total connected load does not exceed the standby generator's rated kW. Temporarily disconnect large loads (HVAC, electric water heaters) and retest. If E05 disappears at lower load, consult an electrician to balance or reduce loads.
• Check air filter: Open the engine access panel and remove the air filter element. If it is dirty or oil-soaked, replace it with a genuine Honda air filter. Do not run the engine without a filter except briefly for testing.
• Inspect fuel system under load: Ensure fuel supply pressure (for NG/LP) or fuel line flow (for diesel/gasoline) is adequate. Check for kinked hoses or partially closed gas cocks. A fuel regulator sized too small for full load can cause underspeed.
• Test run: Reconnect the battery, start the generator with minimal load, then gradually add loads while monitoring for E05. If the engine bogs under moderate load, internal engine or injector issues may be present and require professional diagnosis.