Controller displays AL01 / Low Oil Pressure and generator shuts down shortly after start

Safety first: Turn the generator OFF, open the main breaker to isolate the generator from the load, and disconnect the battery negative cable before working on the engine. Allow the engine to cool fully.

• Check oil level: Remove the engine dipstick on the Kohler-SDMO diesel engine (e.g. KD series). Wipe, reinsert, and check level. Top up with the manufacturer-specified oil grade if below the MIN mark. Do not overfill.
• Inspect for leaks: Look around the oil filter, oil pan gasket, crankshaft seals, and oil cooler hoses for wet oil traces. Tighten loose fittings and replace damaged hoses or gaskets.
• Inspect oil filter: Verify the spin-on oil filter is the correct Kohler-SDMO specified part and properly tightened. If clogged or old, replace the oil filter and refill oil as required.
• Check oil pressure switch: Locate the oil pressure switch on the engine block (usually near the oil filter). Inspect the wiring harness and connector for corrosion or broken wires. Clean contacts and reseat. If the AL01 persists with correct oil level and no leaks, test the switch with a pressure gauge or temporarily substitute a known-good switch.
• Reset and test: Reconnect the battery, clear the alarm on the APM303/APM403 controller, and start the generator while monitoring for leaks and stable oil pressure indication.

If low oil pressure is confirmed with a mechanical gauge, stop the engine immediately and contact a qualified technician—internal engine damage may be present.