Generator fails to start, controller displays E004 and stops cranking

Safety: Allow the engine to cool completely before opening any part of the cooling system. Hot coolant can cause severe burns.

• Check coolant level: When cool, remove the radiator cap or check the expansion tank. Top up with the correct coolant mixture recommended for Perkins engines. Inspect for signs of oil in coolant or coolant in oil.
• Inspect for leaks: Look around hoses, radiator core, water pump, and core plugs for dried coolant stains or wet areas. Tighten clamps or replace hoses as needed.
• Clean radiator and airflow path: Remove debris, dust, and leaves from the radiator fins and engine enclosure louvers. Use low‑pressure compressed air from the engine side outwards to avoid fin damage.
• Check coolant temperature sensor: Locate the coolant temp sender on the cylinder head or thermostat housing. Inspect wiring and connector. Compare the controller’s temperature reading with an infrared thermometer on the housing. Replace the coolant temperature sensor if readings are clearly incorrect.
• Thermostat and pump: If overheating occurs quickly after start, the thermostat may be stuck closed or the water pump impeller may be damaged. These require draining coolant and mechanical disassembly; if you are not experienced, contact a Perkins service technician.
• Reset and test: After correcting issues, clear E004 on the controller and run the set under light load while monitoring temperature.