Dishwasher F12 error

Hello, I have persisting problem with my dishwasher Etna. Few days ago it showed error F12 and was not running anymore. I was trying to find the problem and I thought I did: the dishwasher water tap was stuck and didn't let even one drop of water through. Great, I fixed the tap which is now running properly again, I cleaned filters in the intake hose and dishwasher itself.... But the F12 error is still there. Does someone know what to do please? Is it a time to call mechanic?