Display shows E4 and the air fryer will not start or stops mid-cycle.

Safety first: Unplug the air fryer before opening any panels. Do not continue to run the unit on a circuit that repeatedly trips or dims lights.

Step-by-step checks:

• Dedicated outlet: Plug the GoWISE USA air fryer directly into a wall outlet with no extension cord and no other high-wattage appliances on the same outlet.
• Check for circuit overload: If lights dim or breakers trip when the air fryer starts, move it to a different circuit or reduce other loads on that circuit.
• Outlet inspection: Inspect the outlet for signs of heat damage or looseness. If the plug feels loose in the outlet, have the outlet replaced by an electrician.
• Internal wiring check (advanced): With the unit unplugged, remove the bottom or rear cover and verify that all spade connectors and screw terminals on the internal wiring harness are tight and fully seated.
• Test again: After ensuring a solid power source and tight connections, plug in and test at a moderate temperature. If E4 returns, the control board’s low-voltage detection or power supply may be defective.

When to stop: Persistent E4 after verifying household power and wiring indicates a failing control board. Replacement is recommended via a qualified service provider.