Dryer displays E04 and stops; often associated with overheating or very hot cabinet surfaces.

Safety first: Disconnect power and allow the dryer to cool completely before working near the heater.

Airflow and cleaning:

• Remove and thoroughly clean the lint filter and any secondary filters.
• On condenser/heat pump models, remove and wash the condenser/heat exchanger as per the user manual.
• Vacuum lint from accessible ducts and the fan housing (accessed from rear or side panel depending on model).

Check thermostats and heater:

• Remove the rear panel to access the heater housing.
• Locate the high-limit thermostat(s) and thermal cut-out(s) mounted on the heater duct. Test each for continuity with a multimeter. Any open device that does not reset when cooled must be replaced.
• Test the heating element for continuity and for shorts to earth (check resistance between each heater terminal and the metal chassis; it should be open/OL).

After replacing any faulty thermostat or heater: Reassemble, restore power, and run a low-heat cycle while monitoring for abnormal heat or smells. If E04 recurs despite good airflow and new safety devices, the control board may be misregulating heater power and should be evaluated by a professional.