Error 55.A is an internal communication error. It typically indicates a communication error between the formatter and the DC controller. The most common cause of this error is normally related to the fuser.
Some steps to try:
1. Turn off and turn on the printer to clear the error message. If the error returns after doing this, then, check external printer connections.
a) Remove the formatter.
b) Reseat any memory DIMMs and EIO cards.
c) Reseat the formatter.
2. If the printer has a duplexer installed, remove it. Turn off and turn on the printer, and see if the error clears. If the error clears, then, the duplexer PCA may be defective. Replace the duplexer.
NOTE: With a worn fuser, the 55.A error usually manifests itself while duplexing, however in extreme cases, the error could appear without a duplexer.
3. Verify that there is no issue with the site power. If the printer is on a surge protector or a UPS, remove it, and plug the printer directly into a wall outlet. If the printer is plugged directly into a wall outlet, try it on another outlet, preferably one that is on a different circuit.
4. Print a PCL configuration page to verify the number of pages since last maintenance. If the printer is close to the 350,000-page service interval, then install a maintenance kit.
If the service interval is not near the 350,000-page interval, then, replace the fuser. Many refurbished and re-manufactured fusers are available at retail; the color of the fuser rollers indicates if it is an HP fuser. Genuine HP fusers will always have black rollers.
