E15 error will not reset after fix

The dishwasher has E15 error code. Water leak after replacing heatpump. Removed styrofoam float and dried the sump. Continuity of switch is okay. Error code persists and will not reset. I have also cleaned the filter and removed the water pump to check it. Flushed clean water thru it. I FINALLY FIXED IT - to get the control board to reset I removed all cables from it and voila!