Generator will not start and the controller displays E01 shortly after a start attempt.

Safety first: Turn the generator to OFF, disconnect the battery negative cable, and ensure the unit cannot start automatically. Allow the engine to cool before working around it.

• Check oil level: Remove the dipstick and verify oil level is between the marks. Top up with the oil grade specified in the Lifan manual (typically SAE 10W-30 or as specified) and reinsert the dipstick fully.
• Inspect for leaks: Look around the oil filter, drain plug, crankcase gasket, and oil cooler (if equipped) for wet oil. Tighten fittings or replace gaskets as needed.
• Test the oil pressure switch: Locate the oil pressure switch on the engine block. Disconnect its wire and check continuity to ground with a multimeter. With engine off, most Lifan switches are normally closed to ground; if it is open or shorted regardless of pressure, replace the oil pressure switch.
• Check wiring: Trace the harness from the oil pressure switch to the Lifan digital controller. Look for pinched, corroded, or broken wires and repair with proper crimp connectors and heat-shrink.
• Clear the code: Reconnect the battery, set the controller to MANUAL, and attempt a restart. If E01 persists with correct oil level and a new switch, internal oil pump or bearing issues may exist and a technician should test actual oil pressure with a mechanical gauge.