Air fryer will not heat; display shows E4 shortly after starting a program.

Safety first: Disconnect from mains and wait until the unit is completely cool before opening.

• Access heater: Remove the top or rear cover to expose the heating element assembly. Note the routing of wires and take photos for reference.
• Check connections: Inspect the heater terminals and spade connectors for burning, discoloration, or looseness. Tighten or replace connectors as needed.
• Test heating element: With a multimeter, measure resistance across the heater terminals. Typical values are between 10–40 Ω depending on wattage. An infinite (OL) reading indicates a failed open heater that must be replaced.
• Inspect wiring: Follow the heater wires back to the main control board and high-limit thermostat. Repair any burnt or broken wires using high-temperature rated cable and proper crimp connectors.
• Relay/board check: If the heater tests good but does not energize, the heater relay on the main control PCB may be defective. Check for burnt relay contacts or board damage. Replace the board if necessary.