MFC 5440cnz I get

Unplug the printer from power cord.Press and hold the "menu" button, then plug the device.You'll see on the LCD screen a "machine error" code.If this code is 40,41 or 4F the print head is defective.If the error is 48 - defective print head cable or circuit board.If the error is 50 or 51 there is error in Purge unit and printer require service.If the error is 46 the waste ink tank is full.Follow this:
Enter 80, then scroll down with the arrow down (round) key. You'll find an entry listed as purge count. If number is over 6000, enter 2 7 8 3.This will reset the purge count value. Then restart the printer, hopefully without the annoying cannot clean message.