Display shows E4 and cooking cannot be started.

Safety first: Disconnect power and let the unit cool completely. Do not bypass safety thermostats.

• Allow extended cool-down: Leave the unit unplugged for 30–60 minutes, then plug back in and test. Sometimes E4 is latched until the internal temperature drops.
• Check for obstructions: Inspect the cooking chamber and rear vents for foil, parchment paper, or food debris that could block airflow around the heater.
• Clean heater area: Carefully clean the heating element and surrounding area to remove carbonized grease that can cause localized overheating.
• Inspect high-limit device: If you can access the internal components, locate the high-limit thermostat or thermal cutoff near the heater. Check for discoloration or signs of overheating.
• Replace thermostat/fuse: If the high-limit device tests open (with a multimeter) and does not reset, replace it with the correct Instant-rated thermostat or thermal fuse.
• Control board evaluation: If the high-limit device is good but E4 persists, the control board’s temperature monitoring circuit may be defective and require replacement.