Air fryer beeps and shows E2 shortly after starting a cooking cycle.

Safety first: Unplug the Ultima Cosa air fryer and allow it to cool fully before inspection.

• Visual inspection: Remove the rear cover to access the cabinet temperature sensor and wiring. Look for melted insulation, bare wires touching each other, or oil/condensation inside the connector.
• Clean connector: If the sensor plug is oily or wet, disconnect it and clean both sides with isopropyl alcohol and a cotton swab. Let it dry completely before reconnecting.
• Check for shorts: With the sensor unplugged from the control board, use a multimeter in resistance mode across the sensor pins. A very low resistance (near 0 Ω) indicates a shorted sensor. Also check from each sensor lead to the metal chassis; there should be no continuity.
• Repair wiring: If the harness is melted or the wires are touching, cut out the damaged section and splice in new high-temperature wire using crimp connectors and heat-shrink tubing. Secure the harness away from the heating element with high-temp cable ties.
• Replace sensor: If the sensor itself is shorted, install a new Ultima Cosa-compatible NTC temperature sensor and route it as originally installed.

If E2 persists with a new sensor and good wiring, the main control PCB may be misreading the sensor and should be replaced by a technician.