A washer symptom. A clear starting point.
LG WM4000HWA
The operating guides cover US WM4000HWA with manual MFL71728908 Rev.02_051022. Each guide checks the full model, control panel and manual before any steps.

If there is an active leak, burning smell, damaged wiring, hot water or unsafe access, pause the checklist and seek appropriate help. Do not open covers, reach into pumps or run another cycle just to fill in this record.

OE or water left in the drum
Begin with the visible drain-route checklist. Its result explains whether the separate filter task is appropriate. A code alone does not identify a failed pump.
https://csl-13-appliance-repair.pages.dev/tasks/lg-oe-drain/
Excess suds or detergent residue
Use the suds plan to record detergent conditions and decide whether a separate drawer-cleaning task is indicated.
https://csl-13-appliance-repair.pages.dev/packs/lg-suds-plan/
UE or a load that will not settle
Use the load-balance observations for this model. Record the load and what happens; do not infer a motor fault.
https://csl-13-appliance-repair.pages.dev/tasks/lg-ue-load/
CL and controls that do not respond
Compare the exact panel labels before following the Control Lock guide. Similar buttons can have different functions.
https://csl-13-appliance-repair.pages.dev/tasks/lg-control-lock/

RECORD BEFORE YOU MOVE ON
- Exact display characters, including whether the display was blank
- When in the cycle it happened and whether water remained
- What you checked safely, what changed and what remains unknown

Unknown model or unresolved condition: https://csl-13-appliance-repair.pages.dev/start/service-record/

Reference: https://www.lg.com/us/support/help-library/lg-washer-what-is-a-front-load-washing-machine-oe-error-code--1337714738535
General symptom context. Use the matching manual and the complete linked guide for this model.