When a cartridge is refilled, it cannot tell it is full. You may receive an error 1686 or a message stating:"The function for detecting the remaining ink level will be disabled since the ink level cannot be correctly detected. If you want to continue printing without this function, press the printers Stop/Reset button for at least 5/five seconds."
Hold down your Stop/Reset button for 5-7 seconds to reset the Canon cartridge. This reset will not give you accurate levels, however it will allow you to continue to print.