Safety first: Disconnect the appliance from the mains before any inspection.

Steps to troubleshoot E4:

Check power source: Plug the air fryer directly into a wall outlet (no extension cord or power strip). Avoid sharing the circuit with high-load devices (kettle, microwave).
Test outlet: Use another appliance to confirm the outlet is stable. If lights flicker or other devices reset, have an electrician check the circuit.
Inspect power cord: With the unit unplugged, examine the Princess power cord for cuts, kinks, or burn marks. Replace the cord set if damaged.
Internal inspection: Remove the outer housing to access the main control PCB. Check for swollen capacitors, burn marks, or loose connectors in the power supply section.
Board replacement: If visible damage is present or E4 persists despite a stable power supply, replace the main control PCB with the correct Princess part number. Transfer any wiring harnesses one by one to avoid misconnection.

If you suspect a household wiring issue, consult a licensed electrician before further use.

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

Possible Causes