Before using the Service Tool for a 6000 error, Canon's official support recommends checking for physical jams or obstructions in the paper feed path. If the error persists, a can sometimes clear the state: Turn off the printer.
Resets the internal counter for the waste ink pads (absorbers).
Is using the Canon Service Tool V6000 Hot legal? In most countries (US, EU, UK), , for personal use. The Magnuson-Moss Warranty Act (US) and EU Right to Repair laws protect your right to repair your own device. However, Canon prohibits distribution of the tool. So downloading it is a gray area; using it is generally legal.