Generator shuts down shortly after start, E-03 displayed

Safety: Allow the engine to cool. Disable automatic start and isolate AC output before working on the unit.

• Check oil level: Use the engine dipstick to verify oil level. Top up with the correct CAT-approved oil grade if low. Do not overfill.
• Inspect for leaks: Look around the oil filter, oil pan, drain plug, and crankshaft seals for fresh oil. Tighten a loose oil filter or drain plug carefully; do not overtighten.
• Verify oil filter condition: If the filter is old or damaged, replace it with a CAT-compatible oil filter. Refill oil and check for leaks.
• Test oil pressure switch: Locate the oil pressure switch on the engine block. Inspect the connector for corrosion or loose fit. With a multimeter, test continuity according to the engine manual (typically closed at low pressure, open at normal pressure). Replace if readings are out of spec.
• Controller check: Clear the E-03 code and start the generator while monitoring oil pressure on the controller (if equipped with a sensor). Shut down immediately if pressure stays low.

If oil level is correct and the switch is good but the engine still reports low oil pressure, do not continue to run it. Internal lubrication issues require a CAT service technician.