The Trailing Cable has been incorrectly connected.
Try the following:
1. Power the Printer OFF disconnect the Trailing Cable. Replace the Trailing Cable if the ends are not flat or are damaged. Reconnect the Trailing Cable correctly, making sure it is pushed in firmly (refer to the instructions on page). Power ON the Printer and check if the Error Code has disappeared.
2. If the Error Code continues, replace the Main PCA taking care when connecting the Trailing Cable.