Oven
F13
The F13 error code on a Siemens oven indicates a fault with the oven’s internal temperature sensor (NTC sensor), meaning the oven cannot accurately read or regulate its cooking temperature. It’s a moderately serious fault — the oven will typically shut down or refuse to heat until resolved.
What does this error mean?
F13 signals that the oven’s control board has detected an abnormal reading from the NTC (Negative Temperature Coefficient) temperature sensor inside the oven cavity. This sensor continuously feeds temperature data to the control board so the oven can maintain the correct heat. When the signal falls outside the expected range — either too high, too low, or absent entirely — the oven throws F13 and stops operating to prevent overheating or unsafe temperature swings.
Est. repair cost
£15–£35 DIY sensor replacement; £80–£160 professional repair (sensor or wiring); £180–£280+ if control board (PCB) replacement is needed
🔍 Likely causes
🛠️ Step-by-step fix
Reset the oven: Switch the oven off at the wall socket (or trip the circuit breaker), wait 5 minutes, then restore power. If F13 clears and doesn’t return, it was likely a transient glitch — monitor for recurrence.
Check the oven is clean around the sensor: Open the oven and locate the NTC sensor probe — it’s usually a small metal pin mounted on the back wall of the oven cavity. If it’s coated in grease or debris, clean gently with a damp cloth and a mild degreaser, then retest.
Inspect the sensor visually: Look for obvious damage — a cracked probe body, burnt or melted wiring near the sensor. If you can see physical damage, the sensor needs replacing. Do not attempt to repair burnt wiring yourself; call a professional.
Test the NTC sensor resistance (if you own a multimeter): Disconnect the oven from power. Access the sensor connector at the back of the oven cavity (no need to open the control board). A healthy Siemens NTC sensor typically reads around 990–1010 ohms at room temperature (20°C). A reading of 0 (short circuit) or OL (open circuit/infinite) confirms a failed sensor.
Replace the NTC sensor: Genuine or compatible Siemens NTC oven sensors are widely available online for £15–£35. The sensor is usually held by one or two screws and connects via a push-fit connector — straightforward to replace without opening any electrical enclosures. Always ensure the oven is fully unplugged before starting.
If the new sensor doesn’t clear F13: The fault likely lies with the wiring harness or the control board (PCB). At this point, stop DIY work and book a qualified appliance engineer — PCB diagnosis and replacement requires specialist tools and carries a genuine risk of electric shock if mishandled.
📞 When to call a professional
Call a qualified appliance engineer if F13 persists after a reset and sensor replacement, or if you find burnt or damaged wiring inside the oven. Tell the engineer: ‘My Siemens oven is showing error code F13 — I’ve already reset it and suspect the NTC temperature sensor or wiring harness.’ This saves diagnostic time and money. Do not attempt to open the oven’s rear control board housing yourself — mains-voltage components inside present a serious electric shock risk.
⚖️ Repair or replace?
A professional repair for an F13 fault typically costs £80–£160 depending on whether it’s a sensor swap or a PCB replacement. If your Siemens oven is under 8 years old and was a mid-to-high-end model (£500+), repair is almost always worth it. If it’s over 10 years old or was a budget model, weigh repair costs carefully — a new built-in electric oven starts from around £300–£400 installed, and modern models are significantly more energy efficient.