This error includes 55.1, 55.2, and 55.3. The engine is not communicating with the formatter. The communication link between the formatter and DC controller was lost. This can occur due to a timing error or intermittent connection between the formatter and DC controller. Reboot the printer. Reseat the formatter, DIMM's and EIO cards. Perform and engine and service test. Replace the DC controller. Replace the formatter.