Cooker
F08
The F08 error code on a Smeg cooker indicates a fault with the oven’s temperature sensor (NTC probe), meaning the appliance cannot accurately read or regulate heat. It’s a moderately serious fault — the oven will typically lock out to prevent overheating or undercooking.
What does this error mean?
F08 signals that the oven’s NTC (Negative Temperature Coefficient) temperature sensor has sent a reading outside the expected range — either an open circuit (no signal) or a short circuit (incorrect signal). The control board interprets this as a sensor failure and shuts the oven down as a precaution. In plain terms: the cooker can’t trust its own thermometer, so it refuses to operate.
Est. repair cost
£15–£40 DIY sensor replacement; £80–£150 professional sensor repair; £200–£280 if control board replacement is needed
🔍 Likely causes
🛠️ Step-by-step fix
Power cycle the cooker: switch it off at the wall socket (or isolate at the fuse board), wait 5 minutes, then switch it back on. A transient fault can sometimes clear this way.
Check your Smeg manual for a model-specific reset procedure — some Smeg ranges require holding a button combination to clear error codes after a power cycle.
Inspect the oven cavity visually: look for any obvious damage, burnt residue near the sensor probe (usually a small metal pin on the oven back wall or side), or signs of a spillage event.
If you’re comfortable with basic appliance work, pull the cooker forward, remove the back panel screws, and check the sensor wiring connector is fully seated. Do not touch any other electrical components — if in doubt, stop here and call a professional.
Source a replacement NTC sensor for your exact Smeg model number (found on the rating plate inside the door frame). Genuine or quality third-party sensors cost £15–£40. Replace the sensor by unplugging the connector and unscrewing the single retaining screw — no specialist tools needed.
After fitting a new sensor, restore power and run the oven on a test cycle at 180°C for 15 minutes. If F08 returns, the fault lies with the wiring harness or control board, and you should book a repair engineer.
📞 When to call a professional
If the error persists after a power reset and sensor replacement, or if you find burnt wiring or a damaged control board, stop and call a qualified appliance repair engineer. Tell them: ‘My Smeg [model number] oven is showing error code F08 — I believe it’s an NTC sensor or wiring fault.’ If your cooker is electric but hardwired (not a plug-in), any internal work beyond the sensor swap should be done by a qualified electrician or appliance engineer.
⚖️ Repair or replace?
A professional repair for an F08 fault typically costs £80–£150 for a sensor and labour, or up to £200–£280 if the control board needs replacing. If your Smeg cooker is under 8 years old, repair is almost always worth it — Smeg appliances are built to last and parts are widely available. Over 10 years old with a failed control board, replacement becomes worth considering, especially given current Smeg range prices starting around £600–£800.