Controller shows E12 and the generator will not start or transfer; may be accompanied by a warning buzzer.

Safety first: Isolate the generator from the load and turn OFF the unit. Disconnect the battery before opening control panels.

• Verify engine speed faults: If other codes (E04/E05) are present, resolve those first. Frequency is directly tied to engine RPM.
• Inspect sensing wires: Locate the small gauge wires from the alternator output to the controller. Ensure they are secure and not damaged.
• Measure frequency (qualified persons only): With proper PPE, start the generator and measure output frequency with a meter capable of Hz measurement. It should be near 60 Hz (or 50 Hz for applicable regions). Large deviations indicate governor or controller issues.
• Controller settings: Confirm that the controller is programmed for the correct frequency and phase configuration for your A-iPower model.
• If E12 persists: The controller or sensing circuitry may be defective. Professional diagnosis is recommended.