Oven
F04
The F04 error code on an AEG oven indicates a fault with the oven’s temperature sensor (NTC probe), meaning the appliance cannot accurately read the cavity temperature. It will typically shut down or refuse to heat as a safety precaution — but in many cases it’s a straightforward fix.
What does this error mean?
AEG ovens use a temperature sensor called an NTC (Negative Temperature Coefficient) probe to continuously monitor the internal cavity temperature. The F04 code is triggered when the oven’s control board detects that the signal from this sensor is out of the expected range — either a short circuit, an open circuit, or a reading that is implausibly high or low. The oven locks out heating to prevent overheating or unsafe operation until the fault is resolved.
Est. repair cost
£15–£35 DIY (NTC sensor part only); £80–£150 professional repair if sensor only; £150–£220 if control board replacement is also required
🔍 Likely causes
🛠️ Step-by-step fix
Power cycle the oven: Switch off at the wall socket or trip the circuit breaker, wait 5 minutes, then restore power. A transient software glitch can occasionally trigger F04 and a reset clears it.
Inspect the oven cavity fan: Turn the oven to fan mode and listen — if the fan is noisy, sluggish, or not running, a blocked or seized fan may be causing genuine overheating. Clean any debris from around the fan opening with a damp cloth (oven fully cold and unplugged).
Locate the NTC sensor: It is usually a small metal probe mounted through the back wall of the oven cavity, secured by one or two screws. With the oven unplugged, remove it carefully and visually inspect for burn marks, cracks, or corrosion.
Test the NTC sensor with a multimeter: A healthy AEG NTC sensor typically reads approximately 10,000 ohms (10kΩ) at room temperature (around 20–25°C). A reading of zero, infinite, or wildly different value confirms the sensor has failed and needs replacing.
Replace the NTC sensor: AEG replacement NTC probes are widely available from UK appliance parts suppliers (e.g. 4ourhouse, Ransom Spares, eSpares) for £15–£35. Match the part number from your model plate (usually inside the oven door frame). Fit the new sensor, reconnect the wiring plug, and restore power.
Check wiring harness connections: If a new sensor does not clear F04, inspect the wiring from the sensor back to the control board for any burnt, pinched, or disconnected wires. Do not open the main control board housing — if the wiring looks intact but the fault persists, stop and call a professional.
📞 When to call a professional
If replacing the NTC sensor and checking the wiring does not clear the F04 code, the fault likely lies with the main PCB (control board) — replacing this requires dismantling the oven’s rear panel and handling mains-voltage components, which should only be done by a qualified appliance engineer. Call a professional and tell them: ‘My AEG oven is showing an F04 error, I’ve already replaced the NTC temperature sensor and the fault persists — I suspect the control board.’ This will save diagnostic time and cost.
⚖️ Repair or replace?
A professional repair for an F04 fault — including labour and a control board if needed — typically costs £120–£220 in the UK. If your AEG oven is under 7 years old and was mid-range or premium, repair is almost always worth it. For ovens over 10 years old where the repair cost approaches 50% or more of a comparable new model (new built-in electric ovens start around £300–£400), replacement is the more economical choice.