What Does It Mean When My Generator Displays an Error Code: RPM Sense Loss, Code 1501, 1505, 1511, or 1515?

RPM Sense Loss Errors

An RPM sense loss error indicates that the generator's control panel does not sense a valid RPM signal. This error is usually caused by a bad battery or battery cable issue.

Note: RPM sense errors cover error code numbers 1515 through 1521. End-user troubleshooting remains the same regardless of the error code. Some error code numbers are exclusive to liquid-cooled units.

Other causes include air pockets in the fuel, dirty fuel, or bad spark plugs. Additionally, we recommend checking to ensure the generator has not been overloaded.

Troubleshooting

If a unit is running and shuts down, attempt to restart:

1. Clear the alarm by turning the unit to OFF and pressing the ENTER button twice, then press AUTO.
2. If the unit does not restart, remove some of the loads that the generator is attempting to power then try putting it back in AUTO and attempt to restart.
3. If the unit continues not to start after these steps, contact an authorized service dealer.

If the unit will not start in AUTO when there is utility loss:

1. Clear the alarm by turning the unit to OFF and pressing the ENTER button twice, then press AUTO.
2. Using the control panel, press ESCAPE.
3. Using the arrow keys, highlight the SUB MENUS option, then press ENTER.
4. Using the arrow keys, highlight the MAINT. option, then press ENTER.
5. Using the arrow keys, highlight the BATTERY option, then press ENTER.

Check the Battery

If this menu states CHECK BATTERY, have the battery tested and replace if needed. Reach out to a local service dealer: How Can I Find a Generac Service Dealer in My Area? If you feel comfortable, you can test the battery yourself: How can I test if my home standby battery is still good (multimeter test)?

If the battery was proven to be good, check that the battery cables and battery terminals are free of corrosion and are properly secured: How Do I Inspect the Battery On My Home Standby Generator?

Still getting RPM sense loss errors?

If issues persist, contact an authorized service dealer, see the How Can I Find a Generac Service Dealer in My Area? article. In addition to these steps, verify that the battery cable connections are properly connected, tight, and free from corrosion.

For a complete list of home standby error codes see the Where can I find a list of error codes for my generator? article.

Title	What Does It Mean When My Generator Displays an Error Code: RPM Sense Loss, Code 1501, 1505, 1511, or 1515?

URL Name	What-Does-It-Mean-When-My-Generator-Displays-an-Error-Code-RPM-Sense-Loss-Code-1501-1505-1511-1515