Brother MFC-6800 - Manual (Page 199)

T R O U B L E S H O O T I N G A N D R O U T I N E M A I N T E N A N C E 20 - 20
Toner Empty Indicator
When the toner cartridge is running low, the display shows TONER LOW and
the Toner Empty LED on the control panel flashes on and off to indicate the
toner is low.
The Toner Empty LED light stays on and the display show TONER EMPTY
to indicate that the toner is empty. Once this indication appears, the machine will
not resume printing until you have installed a new toner cartridge.
WARNING
Just after you have used the MFC, some internal parts of the MFC will be
extremely HOT! So, please be careful.
Display Toner Empty Icon