Release both buttons. If the power light stays steady (not blinking), you are in Service Mode.
Under the tab, find "Ink Absorber Counter" and click Set . A "Finished" message indicates the reset is successful. Download Safety and Licensing Canon Service Tool 5306 Download
To use the software, you must first put your printer into : Enter Service Mode: Turn off the printer but keep it plugged in. Press and hold the Stop/Resume button (triangle icon). While holding Stop , press and hold the Power button. Release both buttons
The Canon Service Tool is not a standard consumer download on official Canon Support pages. Canon Service Tool 5306 Download
While some sources offer "free" versions, full functionality often requires a paid activation key.