Should fix any errors starting with U4.
Every 200,000 prints you should replace the fuser maintenance kit of your Xerox Phaser 4500 or 4510 printer. At this time your machine may display "Replace Maintenance Kit." Replacing this will reduce the likeliness of jams, improve print quality and extend the working life of your printer. For the 4500 the part number is 108R00600
This easy-to-replace maintenance kit will keep your Xerox PhaserTM printer operating flawlessly.
108R00600 - Xerox 4500 Fuser Maint Kit 110V, New