How do we fix or replace part. We have shut off the breaker for an extended time, turned back on still same error.

The page linked below has instructions to replace the control board.

https://www.appliancecodes.com/repairs/how-to-access-and-replace-electronic-oven-control-eoc-part-number-316560143-on-a-frigidaire-gallery-slide-in-range/