Generator will not start, control panel shows E01 shortly after cranking attempt

Safety first: Turn the generator OFF, set the fuel valve to OFF, disconnect the battery negative cable, and allow the engine to cool completely before working on it.

• Check oil level: Remove the dipstick and verify the oil level is between the LOW and FULL marks. Top up with the manufacturer‑specified oil (typically SAE 10W‑30 or as per your DuroMax standby generator manual). Do not overfill.
• Inspect for oil leaks: Look around the oil filter, drain plug, crankcase gasket, and oil cooler (if equipped) for signs of leakage. Repair leaks and refill oil as needed.
• Test low oil pressure switch: Locate the low oil pressure switch on the engine block. Disconnect its wire and temporarily start the generator. If E01 clears and the unit runs normally, the switch may be faulty. Do not run long‑term with the switch disconnected; this is for testing only.
• Check wiring harness: Inspect the harness from the low oil switch to the control module for pinched, cut, or corroded wires and loose connectors. Repair or replace damaged wiring.
• If oil level and switch are good: The engine may have an internal lubrication problem (oil pump, blocked pickup, worn bearings). Do not continue to run the unit. Contact a qualified generator technician for oil pressure testing and internal engine diagnosis.