[HELP!] LG washing machine not draining OE Error

LG WT1101CW

I've researched this issue ad nauseum. The OE Error indicates that the drain hose is blocked or the drain pump filter is clogged.

I read a lot about this issue online and most resolutions were to replace the main control board. I just replaced the main board and still have the same problem although immediately after installing it I ran a rinse cycle and it drained fine. After draining fine the first time after replacement, it's back to OE error.

I've checked the drain hose. I've removed the drain pump filter and it doesn't seem clogged and every hose attached to the drain pump filter also isn't clogged that I can tell. I have a new drain pump filter on order already but it's not in yet.

I guess I'm wondering if there's anything else I can check or try in the meantime? We've been without a washing machine for over a week and my wife is losing patience. 😆

I'm determined to fix this myself!