Oster air fryer beeps and shows E3 shortly after starting a cooking program; fan may run briefly then stop.

Safety: Unplug the unit immediately if you see E3 along with smoke or smell burning plastic. Allow it to cool completely before inspection.

E3 often indicates the internal temperature has exceeded a safe limit.

• Check ventilation: Ensure the fryer has at least 5 inches (12 cm) of clearance on all sides and is not pushed against a wall or under low cabinets. Clear any obstructions from the rear and bottom vents.
• Clean the interior: Remove the basket and tray. Clean heavy grease from the heater guard, walls, and especially around the temperature sensor and heating element using a non-abrasive sponge and degreaser. Built-up grease can trap heat.
• Verify fan operation: Start a low-temperature cycle with the basket removed and look up at the fan through the heater guard (do not insert fingers). You should see and hear the fan spinning. If the fan does not run, shut off and unplug the unit.
• Inspect fan and thermal cutoff (advanced): Remove the rear/bottom cover. Check that the fan blades spin freely and are not obstructed by wiring or debris. Inspect the thermal cutoff (small inline thermal fuse near the heater) for signs of overheating. A blown thermal fuse will usually cause no heat, but some models log E3 when it opens intermittently.
• Replace failed parts: If the fan motor is seized or the thermal cutoff is open, replace the faulty component with an Oster-compatible part. Always match the temperature and current rating of the thermal fuse.
• Reassemble and test: After cleaning and part replacement, reassemble the covers, ensure all screws are tight, and test at a low temperature while monitoring for normal fan and heater cycling.