Controller displays E11 and the generator shuts down shortly after starting.

Safety first: Turn OFF the generator, disconnect the battery negative cable, and allow the engine to cool. Verify oil level before assuming a sensor fault.

• Confirm oil level: Check the dipstick and ensure oil is at the proper level. Top up with the recommended oil if needed.
• Locate oil level sensor: On many WEN engines, the oil level sensor is mounted in the crankcase side cover. Disconnect its electrical connector and inspect for oil contamination or corrosion.
• Test sensor: Using a multimeter, measure resistance between the sensor terminal and ground with the engine off and level. Compare to WEN specifications. A reading of infinite resistance or a dead short may indicate a bad sensor.
• Inspect harness: Follow the sensor wire back to the main harness and controller. Repair any chafed insulation or broken conductors. Clean and reseat connectors.
• Replace sensor if faulty: Drain oil below the sensor level if necessary, remove the sensor, and install a new oil level sensor with a fresh gasket. Refill oil and check for leaks.
• Reset and test: Reconnect the battery, clear E11, and run the generator. If the code returns with a known good sensor and wiring, the controller input circuit may be defective and require board replacement.