Oven
F12
The F12 error code on an AEG oven indicates a fault with the oven’s temperature sensor (NTC probe) or its wiring circuit — it’s a moderately serious fault that will prevent the oven from heating safely until resolved.
What does this error mean?
F12 tells you that the oven’s control board has detected an abnormal reading from the NTC temperature sensor — the component responsible for monitoring internal oven temperature. The board is seeing a signal that is either out of range, erratic, or completely absent, meaning it cannot regulate heat safely. This is a protective shutdown: the oven is working as intended by refusing to operate without reliable temperature data.
Est. repair cost
£15–£35 DIY sensor replacement; £80–£160 professional repair (sensor); £150–£280 if PCB replacement is needed
🔍 Likely causes
🛠️ Step-by-step fix
Reset the oven first: switch it off at the wall socket, leave it unpowered for 5–10 minutes, then switch back on and clear the error. If F12 doesn’t return, a transient power fault was the cause — monitor for recurrence.
Check your oven isn’t overloaded or in a high-ambient environment: ensure ventilation slots around the appliance are clear and unobstructed, as restricted airflow can cause sensor misreadings.
Locate the NTC temperature sensor: on most AEG ovens it is mounted on the rear interior wall of the oven cavity, identifiable as a small metal probe with a two-pin connector. Inspect it visually for obvious damage, burning, or a broken probe tip.
Check the sensor connector: if you are comfortable doing so with the oven fully unpowered and cooled, gently unplug and re-seat the sensor’s wiring connector. A loose connection is a frequent culprit and costs nothing to fix.
Test or replace the NTC sensor: AEG oven NTC sensors are widely available (search your oven’s model number, found on the rating plate inside the door frame). A replacement sensor typically costs £15–£35 and clips or screws into place — no specialist tools needed. If you are unsure, stop here and call a professional.
Do NOT attempt to open the control board housing or inspect internal PCB components yourself — this requires a qualified engineer.
📞 When to call a professional
Call a qualified appliance engineer if the F12 error returns after a reset, or if inspecting the sensor reveals burnt wiring, damaged connectors, or a broken probe that you are not confident replacing yourself. When booking, tell the engineer: ‘My AEG oven is showing error code F12 — I believe it’s an NTC temperature sensor fault.’ This saves diagnostic time and may reduce your call-out cost.
⚖️ Repair or replace?
A professional repair for an F12 fault — covering call-out, diagnosis, and sensor replacement — typically costs £80–£160 in the UK. If the control board (PCB) is at fault, expect £150–£280 including parts. For ovens under 8 years old in otherwise good condition, repair is almost always the better value. If your AEG oven is over 10 years old and repair costs exceed £150, a new built-in oven from £300–£500 is worth serious consideration.