The printer is not correctly in Service Mode. Re-do the button combination.
While the Canon Service Tool V3800 Portable easily solves the digital limitation of your printer, it does not physically empty the waste ink.
Clears errors like 5B00, 5B01, or 1700.
Always take the time to periodically open the lower chassis casing, extract the saturated pads, wash them thoroughly in warm water, dry them fully, and reinstall them alongside your software interventions.
Guide you on to prevent leaks.