Freezer
F6
The F6 error code on a Bosch freezer points to a fault with the temperature sensor circuit — specifically, a problem detecting the internal freezer temperature. It’s a moderate fault: your food may be at risk if left unresolved, so act promptly.
What does this error mean?
F6 tells you that the freezer’s NTC temperature sensor (also called a thermistor) is sending an abnormal or absent signal to the control board. The appliance can no longer confirm what temperature it’s actually running at, so it triggers the error as a safety warning. In most cases the freezer will continue running, but without reliable temperature regulation — meaning it may under- or over-cool without you knowing.
Est. repair cost
£10–£25 DIY sensor replacement; £80–£180 for professional repair including labour
🔍 Likely causes
🛠️ Step-by-step fix
Step 1 – Power reset: Unplug the freezer from the mains socket and leave it off for 10 minutes, then plug back in and power on. A one-off F6 triggered by a power surge may clear immediately.
Step 2 – Check the door seal: Run your fingers around the full perimeter of the door seal looking for cracks, gaps, or sections that have pulled away. A faulty seal lets warm air in and accelerates frost build-up around the sensor. Replace the seal if damaged — Bosch-compatible door seals cost around £15–£35 online.
Step 3 – Defrost the freezer: If frost build-up is visible inside, empty the freezer, switch it off, and allow it to fully defrost over 24 hours with the door open. Excess ice can enccase the sensor and trigger F6. Once defrosted, clean the interior, refit your food, and restart.
Step 4 – Inspect the sensor wiring: After unplugging, locate the NTC sensor (usually clipped to the interior wall or evaporator — check your model’s user manual for the exact position). Visually check the connector and wiring for obvious damage, corrosion, or a loose plug. Reseat any loose connector firmly.
Step 5 – Test and replace the NTC sensor: If you have a multimeter, you can test the sensor’s resistance (a healthy Bosch NTC sensor typically reads around 5,000–10,000 ohms at 0°C). A reading of zero or infinite resistance confirms a failed sensor. Replacement NTC sensors for Bosch freezers cost £10–£25 online and are a straightforward swap for a competent DIYer — unplug the freezer first, always.
Step 6 – If the error persists after steps 1–5, the control board (PCB) is the likely culprit. Do not attempt to repair the PCB yourself — call an engineer at this point.
📞 When to call a professional
Call an appliance engineer if the F6 error returns after a full defrost and sensor replacement, as a PCB fault is likely and requires specialist diagnosis. Tell the engineer the exact error code (F6), your Bosch model number (printed on the interior left wall), and what steps you’ve already tried. A Bosch-approved or Which?-Trusted appliance engineer is your best option for accurate parts and warranty-backed repairs.
⚖️ Repair or replace?
A professional repair for an F6 fault — typically sensor or PCB replacement — costs £80–£180 in the UK including labour and parts. If your Bosch freezer is under 8 years old, repair is almost always the better value. If it’s over 10 years old and the PCB needs replacing (parts alone can be £80–£120), a new freestanding freezer from £250 upwards may make more financial sense long-term.