E4 appears on the display and the unit will not start or stops shortly after starting.

Safety first: Disconnect from mains and allow the appliance to cool. Overheat conditions can damage internal plastic parts and wiring.

• Verify placement and load: Do not cover the top of the air fryer with foil or objects. Avoid overfilling the basket; large loads restrict airflow and cause hot spots.
• Clean the heater area: Remove the basket and drawer. Look up toward the heating element. If there is heavy grease or carbon buildup on the element, fan shroud, or sensor area, clean carefully with a non‑abrasive sponge and mild detergent. Do not spray cleaner directly onto electrical parts.
• Check sensor position: The NTC sensor should be clipped firmly to the metal cavity or bracket near the heater. If it has come loose and is hanging in free air, it may misread temperature. Re‑clip it securely.
• Inspect high‑limit thermostat: Locate the small round thermostat (often with two terminals) on the heater bracket. Some models have a manual reset button; if present, press gently to reset. If it will not reset or has no continuity when cool, it must be replaced.
• Ensure vents are clear: Check rear and side vents for dust or grease. Clean with a soft brush and vacuum.

If E4 persists after cleaning and verifying sensor and thermostat, the main PCB may be misreading the sensor or driving the heater incorrectly and should be evaluated by a service technician.