Universal diagnostic library
Generac home standby-generator alarm codes
Keep the alarm visible and record when it occurred.
Generac home standby generators show alarms for the main ways an engine can fail or shut down to protect itself. The seven pages in this section cover overcrank (1100 and 1101), low oil pressure (1300), high temperature (1400 and 1401), loss of the RPM signal (1500 to 1522), underspeed (1600 to 1603), a fuse problem (2400) and an auxiliary shutdown (2800). Each page says what the controller measured, what you can check safely and when to call a technician.
Generac codes 1500–1522: RPM sensor loss
Codes 1500 to 1522 are the RPM SENSOR LOSS alarm, shown with a red LED. Generac says the controller does not detect a valid RPM signal during startup, or lost a valid signal while running. End-user troubleshooting is the same for every code in the range, and the likely causes differ by whether the unit failed to start or shut down while running.
Open record Generac standby generator · exact alarm familyGenerac codes 1600–1603: underspeed
Codes 1600 to 1603 are the UNDERSPEED alarm, shown with a red LED: engine speed (RPM) is too slow. Generac says the cause is that the unit is overloaded or has fuel supply issues, and the Mobile Link message says an underspeed alarm occurred.
Open record Generac standby generator · exact alarmGenerac generator code 1100 or 1101: overcrank
Codes 1100 and 1101 are the OVERCRANK alarm, shown with a red LED: the unit turns over but will not start, and after the engine has tried to crank 5 times without starting the controller triggers the alarm. Generac lists these common causes: inadequate fuel pressure, the fuel shutoff valve being OFF, improper fuel selection in the controller (Evolution) or in the Field Pro app (Power Zone 200), an air filter problem, improper installation and a low battery.
Open record Generac standby generator · exact alarmGenerac generator code 1300: low oil pressure
Code 1300 is LOW OIL PRESSURE, shown with a red LED: the low oil pressure sensor triggered a shutdown because of inadequate oil. Generac says the cause is typically low oil from oil consumption, leaks or a lack of maintenance, and that your options are limited beyond basic checks and one attempt to clear the alarm and restart.
Open record Generac standby generator · exact alarmGenerac generator code 1400 or 1401: high temperature
Codes 1400 and 1401 are the HIGH TEMPERATURE alarm: the generator is overheated. Generac says the cause is obstructed intake and exhaust ventilation around the unit or inadequate fuel pressure, and asks you to make sure there are no enclosures around the generator.
Open record Generac standby generator · exact alarmGenerac generator code 2400: fuse problem
Code 2400 means the controller’s 7.5-amp fuse is missing, open or not seated on supported Generac platforms. Isolate utility, generator and battery power exactly as Generac directs before inspection.
Open record Generac standby generator · exact alarmGenerac generator code 2800: auxiliary shutdown
Code 2800 or 2801 means the generator was shut down with the Emergency Stop button or, more commonly, an Auxiliary Shutdown switch, shown as STOPPED - ALARM or SHUTDOWN SWITCH with a flashing red LED. Generac says these switches have been required by NFPA fire safety rules since 2017 and sit in accessible places on air-cooled home standby generators. They can be tripped by brushing against one, during maintenance when it was not reset, or even by animals such as squirrels, and a service provider may trip one on purpose so a unit awaiting service cannot run.
Open recordGenerac alarm codes: the seven groups and how to read them
Keep the alarm visible and write down when it occurred, since the history helps a technician. Check the oil level, the fuel supply, the battery and the vents first, because many of these alarms trace back to one of those four. Do not reset an alarm repeatedly and keep restarting a generator that shuts itself down for oil pressure or temperature; the engine can be damaged.
Which Generac alarm means the engine would not start?
Codes 1100 and 1101, overcrank, mean the engine turned but did not start. Check fuel, battery and the starter.
Is it safe to keep restarting a generator after a low oil pressure alarm?
No. Check the oil level and let the engine be inspected before running it again.