Cooker
F03
The F03 error code on a Zanussi cooker indicates a fault with the oven temperature sensor (NTC probe), meaning the appliance cannot accurately read or regulate the oven cavity temperature. It will typically prevent the oven from heating and should be addressed promptly to avoid further damage.
What does this error mean?
F03 signals that the oven’s NTC (Negative Temperature Coefficient) temperature sensor has sent a reading outside the expected range — either an open circuit (sensor disconnected or broken) or a short circuit (sensor shorted out). The control board sees this as an impossible temperature value and locks the oven to protect it. This is an electrical fault on the oven’s monitoring system, not a gas fault, so certain DIY checks are safe to carry out.
Est. repair cost
£10–£30 DIY sensor replacement; £80–£130 professional sensor repair; £200–£380 if control board replacement is also required
🔍 Likely causes
🛠️ Step-by-step fix
Reset the cooker: switch it off at the wall socket (or fuse spur), wait 5 minutes, then switch it back on. If F03 clears and the oven heats normally, monitor for recurrence — a one-off power glitch can trigger false sensor errors.
Check for visible wire damage: with the cooker fully unplugged at the wall, open the oven door and visually inspect the rear oven cavity for any wiring that looks burnt, pinched, or detached. Do not touch internal components — this step is visual only.
Locate the NTC sensor: on most Zanussi electric ovens it is a small metal probe mounted on the back interior wall of the oven cavity, held by one or two screws. Note its position before doing anything further.
Test the NTC sensor resistance (if you have a multimeter): at room temperature (~20°C), a healthy Zanussi NTC sensor typically reads around 9,000–12,000 ohms. A reading of 0 (short) or OL/infinite (open circuit) confirms the sensor has failed and needs replacing.
Replace the NTC sensor: compatible replacement sensors for Zanussi ovens are available from UK spare parts suppliers (e.g. 4ourhouse, eSpares, BuySpares) for £10–£30. Unplug the cooker, unscrew the old probe, disconnect the spade connectors, fit the new sensor, reconnect, and refit. No soldering required.
If F03 returns after sensor replacement, do not attempt to replace the control board yourself — call a qualified appliance engineer, as PCB replacement and programming requires specialist tools.
📞 When to call a professional
Call a qualified appliance engineer if the error persists after a reset and after fitting a new NTC sensor, as the fault is likely in the main control board (PCB) — a repair that involves accessing live electrical components and is not DIY-safe. When you call, tell the engineer the exact model number (found on the frame inside the oven door), the error code F03, and whether the sensor has already been replaced. Expect most engineers to carry Zanussi-compatible sensors on their van.
⚖️ Repair or replace?
An NTC sensor replacement by an engineer typically costs £80–£130 all-in including parts and labour in the UK — well worth it if the cooker is under 8 years old. A control board replacement adds £120–£250 to that bill, so if your Zanussi cooker is over 8–10 years old and needs a PCB, replacement with a new appliance (budget £300–£600 for a comparable model) is often more cost-effective. If the cooker is still under Zanussi’s warranty, contact Zanussi customer service before spending anything.