I corrected the switch at the bottom of the piston, error 12 disappeared.
Currently, the coffee machine seems to be working. That is, it turns on and makes coffee. However, during brewing, the coffee is poured under very low pressure and it sounds like air is getting in somewhere. To be observed here:
krups-bulg..nie.mp4 Download (13.68 MB) The machine made about 5 coffees like this, and during the next one nothing came out of the spout (actually, I don`t even know where the coffee went - there wasn`t much water in the tray, the inside of the machine was dry, there was no leakage from under the machine). You can see it here:
krups-brak..ody.mp4 Download (9.55 MB) After the lack of water situation, the machine returned to its original situation (POWER, CALC and CLEAN flashing). I unplugged the coffee machine, added water to the tank, turned on the coffee machine, put in the tank and managed to make another cup of coffee, but the coffee is still pouring at low pressure and there is a gurgling sound (like in the first video).