Oven
F31
The F31 error code on an AEG oven indicates a fault with the oven’s core temperature sensor (NTC sensor), meaning the appliance cannot accurately read or regulate the oven cavity temperature. It will typically prevent the oven from heating and should be addressed promptly to avoid cooking failures or further damage.
What does this error mean?
F31 signals that the oven’s main NTC (Negative Temperature Coefficient) temperature sensor has sent a reading outside the expected range — either no signal, an open circuit, or a short circuit. The oven’s control board interprets this as a potentially dangerous or unreliable temperature state and shuts down heating as a safety precaution. This is an electrical fault on the sensor circuit, not a gas issue, so cautious DIY investigation is appropriate.
Est. repair cost
£15–£40 DIY sensor replacement; £80–£160 professional repair (sensor or PCB)
🔍 Likely causes
🛠️ Step-by-step fix
Reset the oven: Switch the oven off at the wall socket or isolate it at the fuse board for 5 minutes, then restore power. If F31 clears and does not return, a transient fault caused it — monitor for recurrence.
Check the oven cavity for obvious damage: Open the oven and look at the rear wall. The NTC sensor is typically a small probe (often near the top rear or side wall). Check for visible cracks, burn marks, or a wire that has come loose from its connector.
Inspect the sensor connector: If you can see the sensor wire connector, check it is firmly seated. Do NOT open the oven’s back panel or control housing — that requires a qualified engineer.
Test the sensor resistance (multimeter needed): With the oven isolated from power, unplug the sensor connector and test resistance across the two sensor terminals. At room temperature (~20°C), an AEG NTC sensor should read approximately 4,000–6,000 ohms. A reading of zero (short) or infinite (open circuit) confirms a failed sensor.
Replace the NTC sensor: AEG oven NTC sensors are available from UK spares retailers (e.g., eSpares, 4ourhouse, Currys PC World Parts) for £15–£40. Ensure you match the part number from your model’s rating plate. The sensor typically unscrews from inside the oven cavity and the connector unplugs — no soldering required.
If the new sensor does not clear F31: Stop DIY work here. The control board (PCB) is the next suspect and requires a qualified appliance engineer to diagnose and replace safely.
📞 When to call a professional
Call a qualified appliance engineer if F31 persists after replacing the NTC sensor, if you find burnt or melted wiring inside the oven cavity, or if you are not confident working with electrical components. When booking, tell the engineer: ‘My AEG oven is showing error code F31 — I believe it’s an NTC temperature sensor or PCB fault.’ This saves diagnostic time and money.
⚖️ Repair or replace?
A professional repair for an F31 fault typically costs £80–£160 depending on whether it’s a sensor (cheap part, low labour) or PCB replacement (£60–£120 for the board alone). If your AEG oven is under 8 years old and was a mid-to-high-end model (£500+), repair is almost always worth it. For ovens over 10 years old or budget models under £350, replacement becomes more competitive — a decent AEG replacement starts around £449.