Hello!Thank you for choosing Just Answer for the solution to your problem.My name is Hank, and I am going to assist you with this.
This fault means that either the generator is not producing enough voltage, or the controller can not sense the voltage.
There are many causes for this - almost every part in the genset is suspect.
Troubleshooting this will require a good digital voltmeter.
But I would encourage you to contact an authorized Generac facility for repair under warranty.
If you try to work on it yourself, you could easily void the warranty.