Safety first: Disconnect from mains and let the unit cool.

Check ambient conditions: Ensure the air fryer is used indoors at normal room temperature. Very cold environments can trigger low-temperature faults.
Inspect sensor mounting: Open the housing and locate the NTC sensor. Confirm it is firmly clipped to its bracket or air channel and not hanging loose.
Check connector: Reseat the sensor plug on the control board. Gently wiggle the harness while watching for any looseness or broken pins.
Wiring inspection: Look for partially broken or kinked wires, especially where the harness bends around metal edges. Repair or replace the harness if copper strands are exposed or the wire feels weak.
Sensor replacement: If E4 persists and other components test fine, replace the NTC sensor with a Lakeland-compatible probe, ensuring correct routing and secure mounting.
Control board: If a new sensor does not resolve the issue, the main PCB may have a faulty measurement circuit and will need replacement.

Warning: Avoid pulling on wires to remove connectors; always pull on the plastic plug to prevent internal breaks.

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

Possible Causes