Hi
My normal first step is to turn off any machine that exhibits a problem, and any other machinery to which it is connected eg a computer network etc. Leave it for about 10 minutes ad then restart it. This is sometimes sufficient to clear errors and reset the machine to an operating condition.
If this doesn't work I look elsewhere and in your case found a description of your error here:
Error Codes Canon iR3025 Code E202 0002
Also on this site you can change the make, model, and error code on your machine by using the drop down menus near the top of the page and you can download a pdf format Service Manual for the machine by using the link just above the error table.
Hope this is helpful, if so would you please register that with Fixya
Cheers