Fridge
F5
The F5 error code on a Siemens fridge indicates a fault with the temperature sensor (NTC sensor) in the fridge compartment — it’s a moderately serious fault that means your fridge may not be cooling correctly and food safety could be at risk.
What does this error mean?
The F5 code tells you that the fridge compartment’s NTC (negative temperature coefficient) sensor is sending a reading outside the expected range — either it has failed completely, or it’s detecting a temperature it cannot correct. Siemens fridges use this sensor to regulate the compressor and fan cycles, so a faulty reading can cause the fridge to over-cool, under-cool, or stop cooling altogether. If left unresolved, food spoilage is a real risk.
Est. repair cost
DIY sensor replacement: £10–£25 for the part. Professional repair (sensor or PCB): £80–£160 including call-out and labour.
🔍 Likely causes
🛠️ Step-by-step fix
Reset the fridge: unplug it from the mains, wait 5 minutes, and plug it back in. If the F5 code clears and does not return within a few hours, it was likely a temporary glitch caused by a power fluctuation.
Check the door seal: run your hand around the full perimeter of the fridge door seal feeling for cold air escaping, or close the door on a piece of paper — it should hold firmly. A damaged seal allows warm air in and can overwhelm the sensor. Replacement seals cost £15–£35 and clip or glue in place without any tools.
Inspect for ice build-up: if the back interior wall of the fridge is heavily frosted or iced over, the sensor may be obstructed. Empty the fridge, turn it off, and allow it to defrost fully for 24 hours with the door open. Dry the interior thoroughly before switching back on.
Locate and inspect the NTC sensor: it is usually a small probe clipped to the rear interior wall or evaporator area. Check the wire leading to it for any visible damage, kinks, or disconnected plugs. Gently reseat any loose connectors — do not probe further into the appliance’s electrical components.
Replace the NTC sensor if faulty: Siemens fridge NTC sensors are widely available from UK spare parts suppliers (e.g., eSpares, 4ourhouse) for £10–£25. The part clips or screws into place and connects via a simple plug — a straightforward DIY job if you are comfortable with basic appliance repairs. Always unplug the fridge before replacing any part.
If the error returns after a new sensor is fitted, the main PCB is likely faulty — stop here and call a professional.
📞 When to call a professional
Call an appliance engineer if the F5 code returns after you have replaced the NTC sensor, or if you find burnt wiring, a damaged connector block, or any sign of electrical damage when inspecting the sensor area. Tell the engineer: ‘My Siemens fridge is showing an F5 error code — I believe it’s the fridge compartment NTC temperature sensor, and I’ve already reset the unit and checked for ice build-up.’ This will save diagnostic time and reduce your call-out cost.
⚖️ Repair or replace?
A professional repair for an F5 fault — typically sensor replacement or PCB diagnosis — will cost £80–£160 including labour in the UK. If your Siemens fridge is under 8 years old, repair is almost always the better value choice given that a comparable new fridge starts at £400–£600. If the unit is over 10 years old and the PCB needs replacing (parts alone can reach £80–£120), replacement is worth serious consideration.