Generator will not start, controller displays E01 and immediately shuts down crank cycle

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

• Check oil level: Remove the dipstick and verify oil level is between MIN and MAX. Top up with the oil grade specified in the Wacker Neuson manual (typically 10W-30 or as specified for your engine model). Do not overfill.
• Inspect for leaks: Look around the oil filter, oil pan, drain plug, and crankcase gasket for fresh oil. Repair any obvious leaks before restarting.
• Inspect oil pressure switch: Locate the oil pressure switch on the engine block (often near the oil filter). Check the connector for corrosion, loose fit, or broken wires. Clean contacts and reseat the connector.
• Bypass test (diagnostic only): With the battery still disconnected, unplug the oil pressure switch and check continuity with a multimeter according to the engine spec (usually closed at rest). If the switch is open when it should be closed, replace it. Do not permanently bypass the switch; it is a critical safety device.
• Change oil and filter: If oil is dirty or overdue, drain and refill with fresh oil and install a new OEM oil filter. Reset the controller and attempt a start.
• If E01 persists: Have a technician verify actual oil pressure with a mechanical gauge; internal engine wear or oil pump failure may be present.