Generac Guardian 24kW / Guardian 22kW / Guardian 26kW / Guardian 18kW error codes
54 codes from the official Generac manual (Spark-Ignited Stationary Generators Owner's Manual), each with the manual page. For 35 of them the manual says to contact an authorized service dealer.
Applies to: Generac Guardian 24kW, Generac Guardian 22kW, Generac Guardian 26kW, Generac Guardian 18kW, Generac Protector XG 48kW, Generac Protector XG 40kW, Generac EcoGen 15kW, Generac Protector XG 80kW, Generac Protector 20kW Diesel (RD02025).
| Code | What it means | What to do | Service | Manual |
|---|---|---|---|---|
| Auxiliary Shutdown | Active alarm that must be cleared before the generator can start. | Verify the controller-face emergency shutdown switch is ON (I). Clear the alarm. If equipped, the rocker switch must be set to ON (I) to clear it. | owner | p. 17 |
| Overcrank Over crank | Fault during initial startup. The generator may exceed the normal number of start attempts because air accumulated in the fuel system during installation. | Reset the alarm and restart up to two more times, if necessary. If the unit still fails to start, contact an IASD for assistance. | dealer | p. 19 |
| Battery Problem | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Canbus Error | Listed as a warning. Warnings alert the operator to conditions that do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Charger Missing AC | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Charger Warning | Listed as a warning. Warnings do not disable the unit or require immediate correction. The manual notes a warning appears when the battery requires service. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Check Engine | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Configuration Mismatch | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Controller Fault | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Download Failure | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| E-Stop | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Emergency Shutdown | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Exercise Set Error | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| High Engine Temperature | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Ignition Fault Code | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Low Battery | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Low Fuel Pressure | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Low Oil Pressure | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Missing Cam Pulse | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Missing Crank Pulse | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Over Voltage | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Overload | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Overspeed | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| RPM Sense Loss | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Schedule A Maintenance | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description beyond the maintenance name is given here. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Schedule B Maintenance | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description beyond the maintenance name is given here. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Schedule C Maintenance | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description beyond the maintenance name is given here. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| USB Warning | Listed as a warning. Warnings do not disable the unit or require immediate correction. No specific description given. | Unless correctly trained to correct and clear warnings, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Under Voltage | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| Underspeed | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| WIRING ERROR | Listed as an alarm. The manual gives no specific description. Alarms cause the generator to shut down. | Unless correctly trained to correct and clear alarms, contact an IASD or trained service technician. To clear the message, press OFF on the controller, then ENTER. | dealer | p. 26 |
| INSPECT BATTERY | Yellow LED illuminated in any state. The screen gives additional information about the battery condition. | Check the screen for additional information. Inspect battery. Press ENTER to clear. | owner | p. 35 |
| INSPECT BATTERY | Yellow LED illuminated in any state; the battery needs inspection. | Check screen for additional information. Inspect battery. Press ENTER to clear. | owner | p. 35 |
| INSPECT BATTERY | Yellow LED illuminated in any state. Check the screen for additional information. | Check screen for additional information. Inspect battery. Press ENTER to clear. | owner | p. 35 |
| LOW VOLTS REMOVE LOAD Low Volts Remove Load | The unit will not start in AUTO when utility power is lost. | Check the LEDs and screen for alarms. Clear the alarm and remove household loads from the generator. Put the unit in AUTO and restart. | owner | p. 35 |
| OVERLOAD REMOVE LOAD Overload Remove Load | The unit shuts down during operation because of an overload condition. | Clear the alarm and remove household loads from the generator. Put the unit in AUTO and restart. | owner | p. 35 |
| SERVICE A | Yellow LED illuminated in any state; scheduled Service A maintenance is due. | Check screen for additional information. Perform SERVICE A maintenance. Press ENTER to clear. | owner | p. 35 |
| SERVICE A Service A | Yellow LED is illuminated in any state. Check the screen for additional information. | Perform the indicated maintenance. Press ENTER to clear. | owner | p. 35 |
| SERVICE B | Yellow LED illuminated in any state. The screen gives additional information about the maintenance item that is due. | Check the screen for additional information. Perform SERVICE B maintenance. Press ENTER to clear. | owner | p. 35 |
| SERVICE B | Yellow LED illuminated in any state; scheduled Service B maintenance is due. | Check screen for additional information. Perform SERVICE B maintenance. Press ENTER to clear. | owner | p. 35 |
| SERVICE B | Yellow LED illuminated in any state. Check the screen for additional information. | Check screen for additional information. Perform SERVICE B maintenance. Press ENTER to clear. | owner | p. 35 |
| SHUTDOWN SWITCH | Flashing red LED; an emergency shutdown switch is open and the unit will not start. | Check emergency shutdown switch(es). Set emergency shutdown switch(es) to CLOSED (I). Clear alarm. | owner | p. 35 |
| HIGH TEMPERATURE High Temperature | Red LED. Unit shuts down during operation on a high temperature alarm. | Check LEDs/screen for alarms. Inspect ventilation around the generator, intake, exhaust, and rear of generator. If no obstructions are present, contact an IASD. | dealer | p. 37 |
| LOW VOLTS Low Volts | Unit will not start in AUTO with utility loss due to low voltage. | Check LEDs or app for alarms. Clear alarm and remove household loads from generator. Put into AUTO and restart. | owner | p. 38 |
| STEPPER OVERCURRENT Stepper Overcurrent | Unit will not start in AUTO with utility loss due to stepper overcurrent. | Check LEDs or app for alarms. Contact an IASD. | dealer | p. 38 |
| SERVICE C Service C | Yellow LED flashes in any state, indicating SERVICE C maintenance is due. | Check app for additional information. Perform SERVICE C maintenance. Select "Clear Maintenance" in app to clear. | owner | p. 39 |
| FUSE PROBLEM Fuse Problem | Unit will not start in AUTO when utility power is lost, due to a fuse problem. | Check the ATO 7.5 amp fuse. Replace it with the same type if it is bad. Contact an IASD if the fuse is good. | dealer | p. 40 |
| MISWIRE Miswire | Unit will not start in AUTO when utility power is lost, due to a wiring error. | Contact an IASD. | dealer | p. 40 |
| SERVICE SCHEDULE A Service Schedule A | Warning that Service Schedule A maintenance is due. | Perform SERVICE SCHEDULE A maintenance; press ENTER to clear. | owner | p. 48 |
| SERVICE SCHEDULE B Service Schedule B | Warning that Service Schedule B maintenance is due. | Perform SERVICE SCHEDULE B maintenance; press ENTER to clear. | owner | p. 48 |
| SERVICE SCHEDULE C Service Schedule C | Warning that Service Schedule C maintenance is due. | Perform SERVICE SCHEDULE C maintenance; press ENTER to clear. | owner | p. 48 |
| 1 Blink GGCAC Blink Pattern | GGCAC device has an issue communicating with the generator controller. | Verify cable harness is securely connected to generator controller. Verify generator controller is operational. Replace cable harness if problem persists. | owner | p. 49 |
| 2 Blinks GGCAC Cellular Communication Error | GGCAC device has a cellular communication error. | Inspect environment for metal objects or mechanical interference blocking cellular performance and clear debris if possible. Communicate generator location to Generac for investigation if problem persists. | owner | p. 49 |
| NOT ACTIVATED Cellular communication error | GGCAC device has a cellular communication error. | Inspect the environment for metal objects or other interference that may block cellular performance, and clear any debris if possible. If the problem persists, communicate the installation location to Generac for investigation. | dealer | p. 49 |
IASD: Independent Authorized Service Dealer, the brand-certified service company.
Source: official Generac manual, read 2026-11-02. "Owner" means the manual lists steps you can take; "dealer" means it directs you to authorized service. Fuel, gas and electrical work on generators is for qualified technicians; follow the manual's safety section.