Diagnosis
The machine is detecting a restriction in the air path, but it's not your main lint filter. The secondary condenser filter, which is the real workhorse for catching lint in a heat pump dryer, is likely clogged.
How to Fix It
- Open the door and locate the condenser compartment at the bottom front of the drum opening.
- Pull the filter frame straight out.
- Rinse the blue plastic fins under running water, using a soft brush (like a dish brush) to scrub between every fin until the water runs clear. Do this in the opposite direction of airflow.
- Let it air dry completely before sliding it back in. A wet filter will trigger the error instantly.
If That Didn't Work
Check the exterior vent hose and wall cap for a bird's nest or heavy lint buildup. Even a slight kink in the flexible hose can cause enough back-pressure to trigger the sensor.
Heads Up
You need to clean this condenser filter every 1-2 months, not once a year. It's the #1 cause of performance issues and extended dry times on this model.