The Service Tool will not detect your printer during regular operation. You must manually boot the hardware into before launching the software. Turn off the printer but leave the power cable plugged in. Press and hold the Stop/Reset button. While holding Stop/Reset, press and hold the Power button. Keep holding Power, then release the Stop/Reset button.
Ensure the printer is truly in Service Mode (solid power light, not flashing). Make sure no other printing jobs are stuck in the Windows 10 print queue, and close all other Canon software programs running in the background. Error Code 002 (Function Not Supported) canon service tool v5306 free download windows 10 fix link