This error message is displayed when the Generator CPU board (A9) is
not detecting the X-ray button pressed also if the main CPU (A5) has
commanded the emission with the corresponding CANBus message.
In this case a possible interruption on cable X20-X20 from main CPU A5
to control CPU A9 is possible.

From the main CPU, the signal is routed to the Generator board, using
the CANBus cable X20-X20; check also that this cable is well inserted
and its continuity. Replace it if damaged.

If the error is still present, check the correct insertion of the flat cable
between the Generator CPU board to the Generator board. The cable is
labelled X53-X53; replace it if damaged.