This error typically means a communication problem between control board (brain) and the user interface (front panel). Try opening up the top and unplugging the wire harness from the control board that leads to the user interface and then (if you have any) clean the contacts with "QD Electronic Cleaner" both on cables end and terminal on user interface. Don't use to much.... allow time for ends to dry then reconnect and see if error persists. (Google the cleaner should be available at big box stores and possibly auto parts stores.