Experienced repair technicians on PrinterKnowledge strongly advise against using v3400 on newer printers. They recommend using the v6220 tool (purchased from eBay for ~$10) which is safer and does not lock the printer.
This button sequence is critical. For most compatible Canon printers: canon service tool v3400.zip
While still holding the Stop/Reset button, press and . canon service tool v3400.zip
canon service tool v3400.zip contains a specialized software utility designed to reset the internal "waste ink counter" on various Canon Pixma printer models. This tool is primarily used by technicians and DIY users to bypass hard-stop error messages like "Waste Ink Tank Full" canon service tool v3400.zip