Smeg STX4-3 dishwasher: Cannot set programme

Hello everyone,

I have a built-in Smeg STX4-3 dishwasher. It has a four-button control panel on the top edge of the door.

A few days ago, I tried to set the programme for a load of dishes, but there was no response when I pressed the “P” button (leftmost button). The display continued to show P0, and there was no beep. The only button that produces any response is the button with the clock icon (second from left). A single press changes the display from P0 to a number, usually 20, 21, or 22, and is accompanied by a single beep.

The dishwasher does not make any sounds or show any sort of responsiveness other than the beep when I press the clock button, and also a single beep when I first turn it on.

I have tried a number of different button combinations, holding buttons down, turning the dishwasher on and off, unplugging, etc.

I find it very strange that the clock button causes the numbers 20, 21 or 22 to display. Based on the documentation for this button, I would not expect to ever see these numbers. One bizarre thought has since occurred to me: could this be the current temperature???

Thanks for any ideas!