Generator shuts down during operation and displays E04 on the controller.

Safety first: Turn the generator OFF, disconnect the battery negative cable, and allow the unit to cool completely (at least 30–45 minutes). Do not open the radiator cap on a hot engine.

• Inspect airflow: Remove any leaves, grass, or debris from the intake and exhaust grilles of the WEN enclosure. Ensure there is at least the minimum clearance around the generator as specified in the installation manual.
• Check cooling fan: With the engine off, visually inspect the engine cooling fan or radiator fan. Spin it by hand to ensure it turns freely. If the fan is seized, wobbling, or missing blades, replace the cooling fan assembly.
• Check coolant level (liquid‑cooled): Remove the radiator cap only when the engine is cool. Coolant should be near the top of the neck or at the FULL mark in the overflow reservoir. Top up with the recommended coolant mix. Inspect hoses and the water pump area for leaks.
• Inspect temperature sensor: Locate the engine temperature sensor on the cylinder head or thermostat housing. Check the connector for corrosion and ensure the wiring harness is intact. If the sensor body is cracked or heavily corroded, replace the engine temperature sensor.
• Clean engine fins (air‑cooled): Remove the shrouds as needed and blow compressed air through the cylinder cooling fins to remove dirt and debris.
• Reset and test: Reconnect the battery, clear the E04 code, and run the generator with no load while monitoring temperature. If it overheats again quickly, further diagnosis of the water pump, thermostat, or fan control circuit is required.