The engine ECU has detected a critical, immediate shutdown condition from one or more of the engine sensors and has been read by the generator controller over the CAN bus communications link to the engine ECU.

Sample engine condition that would trigger an ECU red alarm:

Low fuel pressure will cause the engine to shut down if the pressure falls below the threshold factory set by the engine manufacturer.

NOTE  A diagnostic trouble code (DTC) may or may not be displayed on the generator controller along with the ECU red alarm (see note under ECU amber warning).

The engine coolant temperature has reached or exceeded the threshold setup in the generator controller.

Possible causes:

• Low coolant level
• Inadequate air flow through radiator or the generator
• Faulty radiator cap
• Issue with fan motor or electronic controller
• Faulty thermostat

The engine oil pressure has reached or fallen below the threshold configured in the generator controller.

Possible causes:

• Low oil level. Ensure the level is correct on the engine dipstick.
• Incorrect oil specification. Ensure the correct oil is used according to the engine manufacturer’s specifications.
• Clogged or incorrect oil filters.
• Excessively overfilled engine crankcase that can lead to aerated oil, resulting in decreased pressure.

The emergency stop has been pressed, effectively disconnecting power to the ecm keyswitch input, as well as the engine crank signal which prevents the engine from being started.