U1 means it hasn't detected any water coming in. Start the dishwasher & listen. It will run the drain pump for approx. 30 secs. Then you should hear water flowing in & wash pump motor will start at same time. If you don't hear the waterflow in, check the tap is fully open. If motor does not start that will be the cause of the U1. It has to be running to detect the water. If U1 comes up, open the door & look if there is water in the tub. That will confirm tap. hose & inlet valve is okay. Motor not starting could be the start capacitor, faulty wash pump motor, faulty wiring or faulty control board. (Usually the capacitor)
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