55
HP Printer
Severity: CriticalWhat Does This Error Mean?
Error 55 means the formatter board and the DC controller board inside your HP printer have lost communication. These two boards work together to control everything the printer does. This is a serious internal error that may require professional service.
Affected Models
- HP LaserJet 4250
- HP LaserJet 4350
- HP LaserJet 8100
- HP LaserJet 8150
- HP LaserJet Enterprise M600 Series
Common Causes
- The cable connecting the formatter board to the DC controller board is loose or damaged
- The formatter board has failed due to age, a power surge, or a manufacturing defect
- The DC controller board has a fault that is preventing communication with the formatter
- Corrupted firmware on the formatter board is causing the communication to fail
- A power surge damaged the internal communication circuit on one or both boards
How to Fix It
-
Turn off the printer and unplug it from the wall. Wait 60 seconds to allow all capacitors to fully discharge.
This full power cycle resets both the formatter and DC controller boards and can clear transient error 55.
-
Plug the printer back in and turn it on. Watch the control panel to see whether error 55 appears immediately or after the startup sequence.
If it clears and does not return, the error was transient. Print a test page to confirm the printer is working.
-
If you are comfortable opening the printer, inspect the cable that runs between the formatter board and the DC controller board.
This cable is usually a wide flat ribbon cable. Firmly press both ends to make sure the connectors are fully seated.
-
If the printer supports firmware updates, check HP's website for the latest firmware for your model and apply it.
Corrupted or outdated firmware on the formatter board can cause communication errors. A firmware update may resolve it.
-
If the error persists after all of the above, contact a printer repair technician for a board diagnosis and replacement.
A technician can test each board individually to identify which one has failed, saving you the cost of replacing both.
When to Call a Professional
Error 55 is a critical internal hardware error that almost always needs professional attention. Replacing a formatter board costs $80 to $180 depending on the model. Replacing a DC controller board costs $100 to $250. For older printers, compare repair cost to replacement cost before proceeding. Contact HP Support at 1-800-474-6836 to discuss repair and warranty options.
Frequently Asked Questions
What is the formatter board?
The formatter board is the printer's main computer. It receives print jobs from your computer, processes them, and sends instructions to the DC controller. Think of it as the printer's brain — error 55 means the brain and body have stopped talking.
Can a firmware update cause error 55?
In rare cases, a failed or interrupted firmware update can corrupt the formatter board's software. This can cause error 55 to appear after an update. If this happened to you, contact HP Support — they have recovery procedures for failed firmware updates.
Is there any way to fix error 55 myself without a technician?
The only DIY steps are the power cycle and the cable reseat described above. If those do not work, the repair requires board-level diagnosis and replacement. Most people are not equipped to do this at home safely — a technician is the right call.