Philips dehumidifier displays E3 and will not start dehumidifying; sometimes occurs after long operation.

Safety: Unplug the unit before opening the housing.

• Locate the humidity sensor: On Philips dehumidifiers, the humidity sensor is typically near the air intake grille or behind a small vented cover on the front panel, connected to the control board by a small harness.
• Clean the sensor area: Use a soft brush or compressed air to remove dust from the sensor and surrounding grille. Avoid liquid cleaners directly on the sensor.
• Check the harness: Ensure the sensor plug is fully seated on the PCB. Disconnect and reconnect to clear oxidation.
• Visual inspection: Look for corrosion or damage on the sensor board. If the sensor is visibly corroded or cracked, it should be replaced.
• Test operation: Reassemble, plug in, and power on. If E3 clears temporarily but returns, the sensor is likely drifting and should be replaced.

Replacing the humidity sensor module is usually straightforward, but if a replacement does not clear E3, the main control PCB may be defective and should be serviced by a professional.