AEG air fryer powers on but does not heat; display shows E3 after a short delay, fan may still run.

Safety first: Unplug the air fryer and wait until all internal parts are cool. Capacitors on the control board may hold charge; avoid touching bare solder joints.

Steps to diagnose and fix E3:

• Visual inspection: Remove the rear or top cover to access the heating assembly. Look for obvious burn marks, broken heater coils, or discolored wiring.
• Check heater connections: Ensure the spade terminals on the heating element are tight and not oxidized. Clean light oxidation with fine sandpaper and reseat firmly.
• Test heating element: Disconnect at least one heater lead. Measure resistance across the element with a multimeter. Typical values are 10–40 Ω depending on wattage. An open reading (OL) indicates a failed element that must be replaced.
• Inspect thermal fuse / thermal cut-out: Many AEG air fryers include a one-shot thermal fuse in series with the heater. Locate the small cylindrical or disc-shaped device attached to the heater housing. Test for continuity; if open, replace with the exact temperature and current rating part.
• Check control board relay/triac: If the heater and fuse test good, the switching device on the main PCB may be faulty. Look for burnt spots or cracked solder joints around the heater relay/triac. Resolder cracked joints if visible; otherwise, the board may need replacement.
• Reassemble and test: After replacing any faulty parts, reassemble the housing, plug in, and run a preheat cycle. Confirm that the unit heats without showing E3.

Warning: Do not bypass the thermal fuse permanently; it is a critical safety component.