Oven
F05
The F05 error code on a Bosch oven indicates a fault with the oven’s temperature sensor (NTC sensor) or its circuit — it’s a moderately serious fault that will prevent the oven from heating safely until resolved.
What does this error mean?
F05 tells you that the oven’s control board has detected an abnormal reading from the NTC (Negative Temperature Coefficient) temperature sensor, which monitors the internal oven cavity temperature. Either the sensor is reading a temperature that’s implausibly high, or the signal from the sensor to the control board is broken or out of range. Because the oven can’t verify safe operating temperatures, it shuts down as a precaution.
Est. repair cost
£15–£30 DIY NTC sensor replacement; £80–£180 for professional repair (sensor or PCB fault, including labour)
🔍 Likely causes
🛠️ Step-by-step fix
Reset the oven: Switch it off at the wall socket (or trip the circuit breaker), wait 5–10 minutes, then power it back on. If F05 clears and doesn’t return, the fault was a temporary glitch.
Locate the NTC sensor: It’s typically a small probe mounted on the back wall inside the oven cavity. Consult your Bosch model’s manual or search your model number on the Bosch UK website to confirm its position.
Inspect the sensor visually: With the oven cold and unplugged, check the sensor probe for visible damage, burning, or heavy grease build-up. Clean carefully with a damp cloth if fouled.
Check the connector plug: Trace the sensor wire to its connector (usually accessible from behind the back panel inside the cavity or from the rear of the appliance). With the oven unplugged, unplug and firmly reseat the connector to rule out a loose connection.
Test the NTC sensor with a multimeter: An NTC sensor in good condition typically reads approximately 1,000 ohms (1kΩ) at room temperature (~20°C). A reading of zero, infinite, or wildly out of range confirms the sensor has failed and needs replacing.
Replace the NTC sensor: Bosch oven NTC sensors are widely available from UK parts suppliers (e.g., 4WhitGoods, Espares, Buyspares). Ensure you match the part to your exact model number. Replacement is a straightforward unscrew-and-plug-in task on most Bosch models.
📞 When to call a professional
If resetting and replacing the NTC sensor doesn’t clear the F05 code, the fault likely lies with the wiring harness or the main control board (PCB) — both require a qualified appliance engineer to diagnose and replace safely. Call an engineer and tell them: ‘My Bosch oven is showing F05, I’ve already replaced the NTC sensor and the error persists.’ This saves diagnostic time and money. Do not attempt to open or replace the control board yourself.
⚖️ Repair or replace?
A professional repair for F05 — covering diagnosis, parts, and labour — typically costs £80–£180 in the UK depending on whether it’s a sensor or PCB fault. If your Bosch oven is under 8 years old, repair is almost always worth it; Bosch ovens are built to last 10–15 years. If the oven is over 10 years old and the PCB needs replacing, a new mid-range Bosch oven (£400–£700) may be a better long-term investment.