I searched the internet for this error and tyhis is what I got:
The printer failed to properly initialize when powered on. Indicates an internal service error. Turn the printer off for 10 minutes and turn back on. If the message persists, consult service.
I also found this:
55 ERROR (Internal Communication Problem)
1. Replace DC Controller PCA.
2. Replace Formatter PCA.
3. Replace both at same time.
Note: Inadequate site power can cause this error and is often a result of thunderstorms.
1. Replace Interface/Formatter PCA.
1. Check and reseat connectors J4, J5, on the Low Voltage Power Supply, J8, J9, J10 and J15 on DC Control PCA.
2. Replace DC Controller PCA.
3. Replace Formatter PCA.
4. Replace Paper Input PCA.
5. Replace Main Motor PCA or Main Motor.
6. Check/reseat cable between DC Controller and Formatter PCA.