“No detergent added” does not prove there was no detergent in the wash. Automatic dispensing, detergent carried in the load and retained residue are separate possibilities. SUD still needs a detergent/foam investigation before a sensor or pump is blamed.
LG front-load models that display SUD for excessive or unsuitable detergent. Confirm the exact code in the model manual; this is not a universal SD alias claim.
Wait for motion to stop and the door or lid to unlock. Water may be hot. Isolate power and follow the exact manual before any user filter maintenance. Never open a filter against a full drum, force a lock or bypass an interlock.
Compare the behavior
The phrase “no detergent” is an observation about an action, not necessarily the chemistry inside the tub. Making that distinction gives the reader a useful, testable history without inventing a repair.
| Observed state | Interpretation / next step |
|---|---|
| Nothing poured; auto dose still active | A detergent input still exists. |
| Previously soapy laundry | The load may carry detergent in. |
| Repeat SUD with controlled dosing | Document symptoms and seek assessment. |
Code-specific checks
Define what no detergent means
Was nothing poured into the drawer, or was automatic dispensing also off? Was the load already soapy from handwashing or a failed previous cycle? Write down the actual route by which liquid could enter. On an ezDispense model, a manual empty compartment does not establish the automatic tank was disabled.
Do not add more products to counter foam
LG identifies excessive or wrong detergent as the SUD issue. Follow the model’s permitted rinse/cleaning recovery without adding another normal detergent dose. Do not mix vinegar, bleach or other household chemicals as an improvised defoamer. Check the product is HE and review concentration before the next ordinary wash.
Treat persistence as an unresolved condition
If the message continues after the documented recovery and the dosing routes are understood, note whether water also fails to drain or another code appears. A concurrent OE belongs to the drain path. Persistent SUD without an obvious dosing explanation deserves assessment; do not manufacture a percentage likelihood or claim a clean filter proves a particular sensor is faulty.
If the warning returns
Auto/manual double route → correct configuration
Residual product → documented recovery
Persistent unexplained SUD → service.
When to stop and get help
Only carry out maintenance permitted in your model’s manual. For service, note the full model number and suffix, displayed code, selected cycle and what happened during the checks. Leave internal wiring, gas components, pumps and safety devices to a qualified professional. A symptom alone does not identify a failed part.
Sources & references
- LG identifies SUD with excessive or wrong detergent. LG-authored support video title/description
- ezDispense can deliver automatically without a manual dose. Using ezDispense
- LG USA Support: SUD excessive/wrong detergent
- LG: detergent and additive usage
- LG WM4500 exact-family manual, mirror
Based on publicly available manuals, manufacturer support and the references listed here. We have not inspected or tested your appliance. Follow the instructions for your exact model; a guide cannot replace an in-person diagnosis.