Reset Drum and Toner.
Drum
  1. Press (Cancel) to interrupt the error.
  2. Press (Settings) > All Settings > Machine Info. > Parts Life.
  3. Press and hold # until the LCD message changes.
  4. Press Drum.
  5. Press Yes.
  6. Press (Home).
Toner
  1. Open the front cover of your Brother MFC laser printer where you can access its toner cartridge.
  2. Press and hold the Hash (#) button for about 5 seconds to see the toner menu on the screen.
  3. Select the toner you need to reset ( For the TN2345 use TNR-HC or for the TN2315 use TNR-STD-A.).
  4. Select YES to reset.
  5. Close the front cover.
  6. DONE.