Hi can anyone help me with this error code or knows its cause?

The machine was working well until yesterday my client reported that the machine was displaying this error (C-E004)
i've searched on the service manual and i only found that MFPB has a faulty connection if not replace the MFPB.
i already checked the connections but the error dont go away not even with trouble reset

Is there a way to fix this error without replacing the MFPB??
Help please!!