: The tool will not work unless your printer is first put into "Service Mode." How to Enter Service Mode
Canon generally recommends that these services be performed by official service centers to ensure the physical integrity of the device. asia.canon Conclusion
The printer's mainboard/EEPROM is locked. This happens if someone previously attempted to enter Service Mode using the wrong key combinations too many times. A locked EEPROM usually requires a physical chip replacement or physical desoldering. Important Safety Warning: Physical Maintenance Required
Press the Stop button exactly 5 times (6 times for select G-series models). Release Power: Release the Power button completely.