I still see the "Toner Empty" message on the LCD even after replacing the toner cartridge.

Try cleaning the corona wire on the drum unit.
If after cleaning the corona wire you still have problems, remove the drum unit from the MFC and shake it gently,and then re-install it.

Brother strongly recommends that you do not refill the toner cartridge provided with your Printer/ FAX/ MFC. Printing with any 3rd Party consumable may reduce not only the printing quality but also the quality and life of the printer. If damage is caused to the drum unit or other parts of the machine as a result of using non Brother branded products, any repairs required as a result may not be covered by the warranty.

FAQs & Troubleshooting

I still see the "Toner Empty" message on the LCD even after replacing the toner cartridge.