Generator will not start in AUTO mode; controller shows AL01 and start sequence aborts after several crank attempts.

Safety first: Place the generator in OFF mode, open the main breaker to isolate load, and remove the negative battery cable before touching wiring. Never work on the engine when it can start automatically.

• Check fuel level and valves: Verify the day tank and main tank have fuel. Confirm the SDMO fuel shutoff solenoid is opening when the key/controller is in MANUAL START. Ensure any manual fuel shutoff valves are fully open.
• Bleed air from fuel system (diesel sets): Use the manual priming pump on the SDMO fuel filter head. Loosen the bleed screw on the filter, pump until fuel flows without bubbles, then retighten. Repeat at the injection pump if accessible.
• Test the starter battery: Reconnect the battery negative, measure voltage at rest (should be ~12.6 V for 12 V systems or ~25.2 V for 24 V). If below 12.2/24.4 V, charge or replace the SDMO starter battery. Clean and tighten battery terminals.
• Check starter operation in MANUAL: Put controller in MANUAL and attempt a start while observing the starter. If you hear a click but no crank, suspect the starter solenoid or starter motor. If nothing happens, check the starter relay and fuses in the SDMO control panel.
• Reset alarm: After correcting issues, clear AL01 on the controller (usually by pressing RESET/STOP then AUTO) and test an automatic start by simulating a mains failure.