How to fix P22 error

P22 is a somewhat vague error :-(. It's a mechanical error in this case, but a lot of the time it's a damaged scanner. SOMETIMES it can be fixed by reseating the scanner cables. I don't have a G3010 to show the process on, but I did find a video that shows how to open the unit up and check the cables.

If reseating the cables does not help, you will need to replace the scanner assembly. Canon does not directly sell parts for ANYTHING they sell, so you need to go through a 3rd party to get the part if it is even available. Given this is an inkjet and the CISS inkjets are just more expensive disposable hardware (whereas cartridge-based units were cheap, but ink was expensive), parts may not be readily available. Your best bet would be getting a donor printer with the infamous 5B00 error (commonly used waste ink error code, which might vary) to get the part off. I say this because you can't fix that issue without rerouting the waste ink or a full teardown and making an absolute mess, so nobody wants to do it; 5B00 and it's equivalents are a death sentence. But this also means anything outside of the controller board and pads is fair game to pull as long as it doesn't hold waste ink.