First Confirm What the LG Display Actually Says
The customer reported a message about cleaning the exhaust, but the technician had not seen it. A photo and the timing within the cycle were the missing first facts.
Why the exact message matters
Some LG dryers display Check Filter as a routine reminder before a cycle. That is different from a model-specific airflow indication that appears during operation. In this discussion the exhaust was reported clean, but neither the wording nor the timing had been verified.
The same symptom can have a different cause on another dryer. Do not treat a customer's paraphrase as an error code.
What to collect before service
- Photograph the complete display.
- Record whether it appears before Start, during heat or at the end.
- Note whether drying time or temperature has actually changed.
- Clean the lint filter and check the accessible outdoor flap without dismantling the dryer.
When it becomes more than a reminder
Long drying times, unusually hot clothing, weak outdoor airflow or a separate code justify a full airflow diagnosis. The field discussion did not report those observations, so it did not establish a blocked vent or a failed sensor.