Wow, this might be like the thread where the guy gets rid of a DTC by inflating his tire more. I don't know how to help you with this one. But, I think you need to move this to the Gen2 forum.
If the fuel gauge isn’t working, I’d suggest following the “Malfunction in Fuel Receiver Gauge” procedure in the Combination Meter section of the Repair Manual (more info).
In most cars, changing out the AC evaporator involves taking a LOT of the dashboard apart. Hopefully there is just a loose or broken wire that serves the fuel gauge.
Welcome to PriusChat!! Try this workup : https://priuschat.com/attachments/gas_gauge_malfunction-pdf.54449/ If you have DTCs (OBD2 codes) from a reader, please share them here.