Generator cranks but shuts down within a few seconds and displays E02 on the Yamaha controller.

Safety first: Turn the generator OFF and disconnect the battery negative cable. Allow the engine to cool completely before opening any coolant components.

• Check coolant level (liquid-cooled): Remove the radiator cap only when the engine is cold. Coolant should be at the neck or as marked. Top up with Yamaha-approved coolant mix. Also check the overflow reservoir level.
• Inspect airflow: Make sure louvers, intake grilles, and the radiator core are not blocked by leaves, dust, or debris. Clean with low-pressure compressed air from the inside out or a soft brush.
• Verify radiator fan operation: With the unit in MANUAL and running (if it will stay running), observe whether the electric cooling fan starts when the engine warms. If not, check the fan fuse, fan relay, and fan motor connector. Replace the failed component.
• Check for coolant leaks: Look around hose clamps, water pump, radiator seams, and the engine block. Repair leaks and re-fill coolant, then bleed air per Yamaha service procedure.
• Test temperature sensor: Locate the engine coolant temperature sensor. Inspect the connector for corrosion. If the sensor is suspected faulty (E02 appears even on a cold engine), test resistance against Yamaha specs and replace if out of range.
• Reset and test: After corrections, clear the code via the controller and run the generator under light load while monitoring temperature and for reoccurrence of E02.