Hello,
The toner level indicator is based off of an estimated page yield for the toner cartridge. The toner cartridge has a chip that keeps track of the page count and when it reaches the estimated page count, the toner level will be at 0.
The level for the toner cartridge can be at 0 and there can still be toner left since the level is based off of the estimated toner page yield. The printer can't detect the amount of toner powder in the cartridge itself and can only estimate. You can cancel any toner level errors that prevent you from printing and continue printing until you see a drop in print quality, but I would suggest having a toner cartridge ready for replacement..
