LG has programmed in the E1 error code to indicate when the drain pump is running, it is not receiving the back pressure it needs. This is most likely an indication that there is a water leak in the draining system. See below for what to check to fix the E1 error…
An E1 (or AE) Error Code identifies there may be a leak in your LG dishwasher.
A leak may be caused by:
1 – Improper installation of the dishwasher.
2 – Using too much or the wrong detergent.
3 – Dishwasher door leaking.
4 – The dishwasher was not loaded correctly.
5 – Faulty sump motor.
6 – Faulty float assembly.
7 – Leaking sump assembly.