Whirlpool washing machine, model AWO 12963. Fault code - FAILURE FA?

Hi. I have a Whirlpool washing machine, model AWO 12963. It has suddenly developed a fault - LCD code 'FAILURE FA'. The user book suggests a Water Stop Fault. However, the pump continues to run with no water remaining in the machine, and with the unit switched to 'off'. Trying any programme setting has no effect, or the reset button. Unplugging the unit obviously stops everything, but reconnecting the mains supply sets the pump running again. Suggestions please.