Air fryer beeps and shows E4; unit will not start heating. Often appears immediately after pressing start.

Safety first: Unplug the air fryer and allow it to cool. The heater area can remain hot for some time.

Diagnostic steps:

• Visual inspection of heater: Remove the basket and drawer. Look up at the heating element through the top grill. Check for visible breaks in the coil, burn marks, or sagging sections.
• Access the heater terminals: Remove the top cover to expose the heater assembly and wiring. Identify the two main heater terminals and their wires leading to the main board or relay.
• Check connectors: Ensure spade connectors are tight and free of corrosion. Reseat them if necessary. Look for signs of overheating at the terminals (discoloration, melted plastic).
• Continuity test (for experienced users): With the unit unplugged, disconnect at least one heater lead and measure resistance across the heater terminals. A typical air fryer heater is 10–40Ω. Infinite resistance indicates an open heater; near 0Ω may indicate a short.
• Relay inspection: On the main control board, locate the heater relay (usually a small rectangular component). Check for burn marks or cracked solder joints on the underside of the PCB.

Corrective actions:

• Replace the heating element assembly if the coil is open or visibly damaged.
• Repair or replace burnt wiring and terminals with high-temperature rated wire and connectors.
• If the heater tests good but does not receive power when the unit calls for heat, the heater relay or main control board is likely faulty and should be replaced.