Code: 11
Display:
11 Paper Out
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.
Code: 20
Display:
20 Memory Overflow
Description:
A large print job has exceeded the memory capacity of the printer. Verify that the SIMMS or memory cards are seated. Add more memory or simplify the print job. Remember the original hp Laserjet has only 128K of memory available, the LJ has only 512K and neither one is really upgradable.
Code: 21
Display:
21 Print Overrun
Description:
The print job is to complex. Simplify the job by removing font changes etc. Enable page protect if you have and additional 1 MB of memory installed.

Code: 22
Display:
22 Error I/O Config
Description:
Par I/O Error/MIO Error
I/O configuration for the computer or printer is incorrect. Configure is properly.
Check I/O Cable, it could be the wrong cable or damaged.
Code: 23
Display:
23 I/O Not Ready
Description:
The I/O card is not accepting data. May not be connected - check cabling - or it may be defective. Reseat the card and if available, swap with a known working card. Watch the termination's on the network cabling.
Code: 24
Display:
24 Job Memory Full
Description:
The print job is too complex to be processed. Laser printers are page printers and require the entire page to be processed before beginning to print. Simplify the print job by removing font changes and/or graphics. Add more memory.
Code: 30
Display:
30
Description:
An I/O time-out or a prompt for user interaction like a manual feed has been exceeded. Check the I/O connections and make sure the proper media is being used.
This is an unexpected PostScript firmware error. Reseat the PostScript SIMM and/or replace it
PCL file was sent to the printer while in PostScript mode or the PostScript file contains bad data, or you have experienced and application error (crash). You need to check the configuration of your printer and drivers, reset the printer, try issuing an initialization command from within the application. May need to reload your PostScript print driver file.
Code: 40
Display:
40
Description:
Make sure computer and printer are set to the same baud rates. Reset as needed.
Check the MIO card, remove, clean contacts, reinstall. Replace if defective
An abnormal connection break may have occurred during data transfer - Press Continue or Go to clear this error message.
Code: 43
Display:
43
Description:
This indicates a communication problem between the formatter PCA and an optional interface installed (such as a network card). Remove and reseat the optional interface card. If the problem continues, remove the optional interface card and set the printer for standard parallel interface by taking off-line and holding down "Menu" key for 5-10 seconds. Scroll through items until "I/O =" appears and use the /- key to display parallel and the enter key to select. Then put the printer back online and send a test job from the host computer via the parallel cable. If this is successful, you have a problem with the optional I/O card and should replace it or reset it.
Code: 50
Display:
50 Fuser Error
Description:
defective heater, termistor, termoswich, triac
Code: 51
Display:
51 Beam Error
Description:
Loss of beam detect. Improperly seated toner cartridge - remove and reinstall. Laser shutter blocked or damaged. Damaged fiber optic cable. Defective Laser PCA - replace. Defective toner cartridge - Replace with different cartridge, even empty for testing. Bad or loose cable connectors - Scanner to DC Controller - check and tighten connector pins at both ends of cable. Damaged Fiber optic cable - examine for cuts or kinks, replace as necessary. Defective Scanner Assembly - Replace.

Code: 52
Display:
52 Scanner Error
Description:
incorrect scanner speed and is generally the same as an error 51.
Code: 55
Display:
55
Description:
Check the connectors on the DC controller and power supply. If you don't hear the motor immediately and you don't have a paper jam, change the power supply.
Code: 57
Display:
57
Description:
Error 57-1 Incompatible memory can be either top or bottom slot. Also check motor cable connections. Replace main motor. Can also be DC controller.
Code: 59
Display:
59
Description:
Add Memory
Code: 62
Display:
62.X
Description:
Defective Internal Memory - Replace Formatter PCA, check all cables first!
Code: 67
Display:
67 Defective
formatter PCA
Description:
Defective formatter board, try reseating the connectors and any accessories you may have plugged in
Code: 79
Display:
79
Description:
Defective Formatter PCA - Replace with known operational board and try again.
Code: 80
Display:
80
Description:
Improper MIO connection - look at pins on formatter MIO connection
Defective MIO Card - Replace card
Defective Formatter Card - Replace card
Code: 89
Display:
89
Description:
The PostScript ROM's have bent or broken pins inspect the pins and reseat if necessary
Check to see that the ROM SIMM's are in the proper location and oriented properly
This can also be a temporay error, try power cycling the printer
The PostScript ROM's/SIMM are defective