I tried to find a manual for this fast track but could not. IF E1 is pressure sensor related. Then you need a fast track or manual that tells you how to put this unit into diagnostics, to read the water level, read out. The pressure sensors sends a Hertz signal to one board and then that board sends the signal to the other board.
So the pressure signal may not be getting there because of a bad pressure switch.
or switch is good but boards, stacked on each other are not communicating
I had one of these samsungs, had the right signal out of pressure switch, and it displayed the correct numbers in the test.
But it was not communicating between the two boards, and I never found out how you could determine which board was failed, with out buying one or the other. My customer did not want to buy either, and play the board swap game.
hopefully some one can get you a fast track to test the pressure switch.