Description: Paper tray empty or not seated correctly. A buildup of toner on the edges of the tray which slide into the printer can sometimes cause problems. Take a sharp tool, like a razor blade and scrape the buildup off these edges.
Sensor Arm Stuck or Broken - check for free movement of the sensor arm.
Defective Tray Size Sensing or Configuration - Most trays have tabs which depress a series of switches when installed. Verify that the tabs aren't damaged and that the tray switches located in the printer are not damaged. You can depress these by hand and hear them click. Occasionally the contact for the micro switch will get bent and will have to be replaced. Also verify the configuration through the menus on the printer.
Defective Paper Control Sensor PCB - These do fail and will need to be replaced.
Code: 12
Display: 12 Printer Open
Description: Paper path door or top cover open. On the this can be caused by a defective toner cartridge, defective cooling fan, PS4 or PS5 sensors. Also caused by the density adjusting PCA located behind the density adjusting slide switch. This board takes the input from the two sensors and provides info to the DC controller. If the board becomes defective, you will receive an error 12. Easily replaced after removing the top cover and three wiring harness connectors. If you want to attempt board level repair try the electrolytic capacitor, C702, 10 uF 50 VDC.
Code: 13
Display: 13 Paper Jam
Description: Check the paper, make sure it meets the paper specifications for your printer. Tractor feed paper with the edges ripped off doesn't seem to work very well. Extremely heavy or thick paper is also a problem. Check the HP paper specification guide for more info. Be careful with labels, use only labels designed to take the heat generated by the fuser assembly. Regular labels my "ooze" adhesive as they pass through the fuser assembly and literally gum up the works! Also check for any partially peeled labels, this can be a disaster if they come off inside the printer. Check the paper path for toner or paper dust buildup. Look for bits of paper lodged in the path particularly around the sensors.
Code: 14
Display: 14 No EP Cartridge
Description: No toner cartridge or cartridge not fully seated - pull it out and install it again. The connections for the high voltage are made on the left side of the printer so you may want to favor that side as you install the cartridge.
This error message can be caused by a faulty paper control PCA. This is the board mounted to the DC power supply which is in the right front corner of the printer. Press the spring contacts and listen for the micro switches. You should hear a definite clicking.
Code: 16
Display: 16 Toner Low
Description: Toner cartridge is empty or toner in cartridge is not distributed evenly. Gently shake the toner cartridge both from side to side and from front to back. This can generally get you 100 or so more pages.
Bad or dirty cartridge contacts. Look for the conductive contacts on the cartridge and the corresponding contacts in the printer and make sure they are clean and free of contaminants.
Defective High Voltage power supply or DC controller to High Voltage power supply can be defective. Check for opens on the cable.
Code: 18
Display: 18 MIO Not Ready
Description: The printer is not connected to a LAN when it's expecting to see a LAN. Terminate the port on the printer with a BNC T and two 50 ohm termination's.
The MIO card is defective or maybe just not seated correctly. Remove the card and reseat it, try swapping with a know good card from another printer. Replace if necessary.