When this error occurs, you must go into Service Mode and clear the error code. How to clear the error code:
1. Enter Service Mode: Press * Additional Functions, 2 and 8 simultaneously, then * Additional Functions again.
2. Then select the [COPIER] option. Under [COPIER], select the Function tab.
3. Under the [FUNCTION] tab, select the [CLEAR] option.
4. In [CLEAR] there is a selection E355-CLR. Select it and hit OK.
5. Reboot the machine.
If the error occurs again:
1. Make sure the connection is secure and tight to the Main-Controller board from the connector cable to the Serial Number board below.
2. Re-seat the Main-Controller board into its slot.
3. Go into service mode and clear the error code as explained above.
* If the error still continues, you probably have a bad Serial Number board and it needs to be replaced.