zanussi fjs 1425w error code e54?

My Zanussi refuses to start. When I select a program and hit Start/Pause it beeps but fails to start, when I have managed to get it started it stops during the cycle and I can't get it restarted. When I set in diagnostic mode (hold Start and Reset during power on) and select any test it returns E54. When I restart after diagnostic mode it starts to fill then stops again - please help