rother MFC 9440CN Toner Life End Message
Reading further, I became convinced that a reset process similar to that used to solve this problem for the Brother 2040 and 7420 models was also required here.With nothing more to go on than responses to my emails from the good people (knuckleheads) at Brother telling me only how to install a new cartridge, I began poking around on my own 'till, after much swearing and gnashing of teeth, I figured it out:

1. With power on, open the toner access main door (You will get a "door open" message in the LCD.)
2. Hit the "Clear/Back" button you go right to the “Toner Reset Menu”.
3. Using the up ^ Down > "Search" arrow buttons, you can then scroll through reset options for each of the printer's [4] toner cartridges!
Code: B. = black; C. = cyan; M. = magenta and Y. = yellow
4. For each for these cartridges is the option to reset for low yield = S (small?) or High Yield = H
5. Using the number keypad, select option #1 (to reset each to the size you have installed.
6. Hit the "Clear/Back" button to get out of the menu, close door.