Safety: Unplug the unit before servicing. Avoid touching live circuits.

Basic reset: Disconnect power for 10 minutes, then power back on. If E3 reappears, continue.
Clean the air path: Remove and clean the air filter. Excess dust can affect humidity readings and cause sensor errors.
Locate humidity sensor: On many TCL dehumidifiers, the humidity sensor is mounted near the air intake grille or on a small board behind the control panel. Remove the front panel/control panel bezel to access it.
Inspect and clean: Check the sensor for heavy dust or corrosion. Gently clean with compressed air or a soft brush. Do not soak the sensor.
Check connections: Ensure the sensor plug is fully seated on the control board. Inspect the harness for damage.
Replace sensor: If cleaning and reseating do not clear E3, replace the humidity sensor assembly with a TCL-approved part. Mount it in the same location and orientation to ensure accurate readings.
Control board replacement: If a new sensor does not resolve E3, the main PCB humidity circuit is likely defective and the board must be replaced.

Dehumidifier shows E3 and compressor does not start; fan may operate intermittently.

Possible Causes