Cooker
F02
The F02 error code on a Smeg cooker indicates a fault with the oven’s temperature sensor (NTC probe), meaning the appliance cannot accurately read the internal oven temperature and has shut down as a safety precaution. It’s a moderately serious fault — your oven won’t heat until it’s resolved — but in many cases it can be diagnosed and fixed without an expensive call-out. In this guide, you’ll learn exactly what causes F02 on Smeg cookers, what you can safely check yourself, when to call a professional, and whether repair or replacement makes more financial sense.
What does this error mean?
On Smeg cookers and range cookers, the F02 error code signals a problem with the NTC (Negative Temperature Coefficient) temperature sensor inside the oven cavity. This small probe — usually a thin metal rod or bulb attached to a short wire harness — continuously monitors the temperature inside the oven and sends real-time readings to the main control board. When the control board receives a reading that is outside its expected range (either an open circuit, a short circuit, or a wildly incorrect temperature reading), it triggers F02 and disables the oven heating function to prevent overheating or unsafe operation. In plain terms: your cooker’s ‘thermometer’ has either failed, become disconnected, or is giving a reading the control board simply doesn’t trust. The hob burners or rings on most Smeg models are unaffected by this fault, so you can still cook on the hob while you investigate.
Est. repair cost
£15–£40 for a DIY NTC sensor replacement; £80–£150 for a professional sensor repair; £150–£300+ if the PCB is faulty
🔍 Likely causes
🛠️ Step-by-step fix
Step 1 – Power cycle the oven: Switch the cooker off at the wall socket or isolate it at the fuse spur or consumer unit, wait a full 5 minutes, then restore power. This clears any temporary electronic glitch in the control board. If F02 disappears and does not return, no further action is needed — but monitor the oven closely.
Step 2 – Check the oven is fully cool before proceeding: Never inspect internal components on a warm oven. Allow at least 30–45 minutes after last use. You’ll need a Torx T20 or Phillips PH2 screwdriver for the steps below.
Step 3 – Locate the NTC temperature sensor: Open the oven door and look inside the oven cavity. On most Smeg single and double ovens (including the SF399X, A2, and Victoria range cooker series), the NTC probe is mounted on the back wall or side wall of the oven interior — it looks like a small metal rod or bullet-shaped probe, usually held in place by one or two screws.
Step 4 – Inspect the sensor and its visible wiring: Look closely at the probe and the wire running from it into the back wall. Check for any visible burning, scorch marks, melted insulation, or corrosion. If the probe looks physically damaged or the wire insulation is melted, do not attempt to use the oven — replace the sensor (see Step 6) or call a professional.
Step 5 – Check the sensor connector (if accessible): On some Smeg models, the wiring connector for the NTC sensor is accessible just inside the back panel of the oven without removing major components. Carefully press it firmly to reseat it. A loose connector is a surprisingly common and easy fix. Do NOT dismantle the back panel or access any other electrical components.
Step 6 – Test or replace the NTC sensor (DIY-friendly): The NTC sensor is a user-replaceable part on most Smeg ovens. Unscrew the one or two retaining screws, pull the probe out gently, and unclip the connector. Use a multimeter set to resistance (Ohms) — at room temperature (around 20°C), a healthy Smeg NTC probe typically reads approximately 9,000–12,000 Ohms. A reading of zero (short circuit) or infinity (open circuit/OL) confirms the sensor has failed. Replacement Smeg NTC sensors are available from Smeg UK spare parts (smegspares.co.uk), eSpares, 4ourhouse, or BuySpares for £15–£40 depending on your model. Always quote your full model number (found on the rating plate inside the oven door frame).
Step 7 – Fit the replacement sensor: Clip the new sensor’s connector onto the wiring harness, insert the probe into the mounting hole, and secure with the retaining screws. Do not overtighten. Restore power and check whether F02 has cleared.
Step 8 – If F02 persists after a new sensor: The fault likely lies in the wiring harness between the sensor and the PCB, or in the PCB itself. Do not attempt to trace or repair internal wiring or work on the PCB — this requires dismantling the appliance’s back panel and working near live electrical components. Stop here and call a qualified appliance repair engineer.
Step 9 – Document everything before calling a professional: Note down the full model number and serial number from the rating plate, the exact error code (F02), and everything you have already tried (power cycle, sensor check/replacement). This will save time and money on the call-out.
📞 When to call a professional
You should call a qualified appliance repair engineer if: F02 returns after a power cycle and you are not comfortable removing the NTC sensor yourself; the sensor tests fine on a multimeter but F02 persists (suggesting a wiring or PCB fault); you notice any burning smell, scorch marks, or melted wiring inside the oven cavity; or the fault reappears shortly after you’ve replaced the sensor. When you call, tell the engineer: ‘My Smeg [model number] oven is displaying an F02 error code, which I understand relates to the NTC temperature sensor. I have already [power cycled / replaced the sensor — delete as appropriate] and the fault persists.’ This helps them come prepared with the right parts. Look for an engineer registered with either NICEIC or a member of the Domestic Appliance Service Association (DASA). Smeg UK (0344 557 9907) also offers an official repair service and can arrange a Smeg-trained engineer if your appliance is under warranty or extended cover.
⚖️ Repair or replace?
For a straightforward NTC sensor replacement that you carry out yourself, the cost is minimal (£15–£40 for the part) and is absolutely worth doing on any Smeg oven regardless of age. For a professional repair involving sensor replacement only, expect to pay £80–£150 including labour and call-out — still good value on a Smeg, which is a premium brand with parts well-supported in the UK. If the fault is traced to the main PCB, professional repair costs rise to £150–£300+, at which point the age and original purchase price of the oven become critical. As a rule of thumb: if the oven is under 7 years old and the PCB repair costs less than 50% of a comparable new Smeg oven (typically £600–£1,800 for Smeg freestanding cookers), repair is the sensible choice. If the oven is over 10 years old and the PCB has failed, replacement is worth serious consideration — particularly as Smeg regularly updates its range with improved energy efficiency and newer features. Smeg parts availability in the UK is generally good for models up to around 12–15 years old, but can become patchy beyond that, which is worth checking before committing to an expensive repair.