An error has occurred in Printhead detection.
Try the following:
1. Switch the Power OFF from the back of the Printer and disconnect the Power cord. Reconnect the power cord and power On the Printer.
2. Remove the Printheads from the Carriage Assembly and reinsert them.
3. Replace the Printheads.
4. Replace the Carriage Cover (Flex Circuit).
5. Replace the Carriage PCA.
6. Replace the Formatter.