Oven
F4
The F4 error code on a Zanussi oven signals a fault with the oven temperature sensor (NTC probe), meaning the appliance can no longer accurately read or control its internal temperature. It’s a moderately serious fault — your oven will refuse to heat or will shut down mid-cook until it’s resolved.
What does this error mean?
F4 tells you that the oven’s control board has detected an abnormal reading from the NTC (Negative Temperature Coefficient) temperature sensor — the small probe inside the oven cavity that monitors heat. Either the sensor is sending a reading that’s too high, too low, or no signal at all. Without accurate temperature data, the oven’s safety logic cuts heating to prevent overheating or a potential fire.
Est. repair cost
£15–£35 DIY sensor replacement; £80–£130 professional sensor/wiring repair; £150–£250+ if control board replacement is needed
🔍 Likely causes
🛠️ Step-by-step fix
Hard reset first: switch the oven off at the wall socket (or trip the fuse in your consumer unit), wait 5 minutes, then restore power. If F4 clears and does not return, the fault was a temporary signal glitch.
Check for obvious wiring damage: open the oven door and visually inspect the rear interior wall where the NTC sensor probe sits (it looks like a small metal pin or rod). Look for any burnt, melted, or disconnected wires. Do not touch internal wiring with the oven powered on.
Test the sensor resistance (if you have a multimeter): unplug the oven, access the sensor connector (usually behind the back panel — refer to your model’s service diagram), and measure resistance across the sensor terminals. A healthy NTC sensor typically reads 990–1010 ohms at room temperature (20°C). A reading of 0 or infinite resistance confirms a failed sensor.
Replace the NTC temperature sensor: genuine or compatible Zanussi NTC sensors cost £15–£35 online (search your model number, found inside the door frame). The sensor is usually held by one or two screws and has a simple plug connector — this is a straightforward DIY part replacement with the oven fully unplugged.
Check and reseat the sensor wiring connector: even if the sensor tests fine, unplug and firmly reconnect the wiring loom connector at the sensor end and at the control board end. Corrosion on pins can be gently cleaned with electrical contact cleaner spray.
If the sensor and wiring test fine but F4 persists, the control board (PCB) is the likely culprit — at this point, stop DIY and call an engineer, as PCB diagnosis and replacement requires professional assessment.
📞 When to call a professional
Call a qualified appliance engineer if replacing the NTC sensor does not clear the F4 code, or if you find burnt or melted wiring inside the oven cavity — damaged wiring is a fire risk and must not be patched with tape. Tell the engineer: ‘My Zanussi oven is displaying an F4 error, I’ve already replaced the NTC temperature sensor and checked the connector, so I suspect a control board fault.’ This saves diagnostic time and money.
⚖️ Repair or replace?
A professional repair for F4 — covering a sensor replacement or wiring fix — typically costs £80–£130 in the UK including labour. If the control board needs replacing, costs rise to £150–£250+, at which point you should weigh this against the oven’s age. For a Zanussi oven over 8–10 years old needing a PCB, replacement with a new appliance (from around £300) is usually the more cost-effective choice.