Cooker
F03
The F03 error code on a Leisure cooker indicates a fault with the oven temperature sensor (NTC probe), meaning the appliance cannot accurately read or regulate the oven’s internal temperature. It’s a moderately serious fault — the oven will typically refuse to operate until it’s resolved.
What does this error mean?
F03 signals that the oven’s NTC (Negative Temperature Coefficient) thermistor — the sensor responsible for monitoring internal oven temperature — is either reading an out-of-range value, has developed an open circuit, or has failed entirely. The control board receives a signal it doesn’t recognise as valid and shuts the oven down as a safety precaution. This is an electrical fault, not a gas fault, even on dual-fuel Leisure models.
Est. repair cost
£15–£40 DIY (NTC sensor part only); £80–£180 for a professional repair including labour; £150–£250+ if PCB replacement is required
🔍 Likely causes
🛠️ Step-by-step fix
Power off and reset: Switch the cooker off at the wall socket (or trip the circuit breaker), wait 5 minutes, then restore power. If F03 clears and doesn’t return, it was a temporary glitch.
Check the oven cavity: With the oven cold and unplugged, inspect the rear or side wall of the oven interior for the NTC probe — a small metal pin or rod, usually held by one or two screws. Look for visible burn marks, melted plastic, or a broken probe body.
Inspect the sensor connector: Carefully pull the probe slightly forward (it’s usually plug-connected at the back). Check the connector for corrosion, loose pins, or heat damage. Reseat the connector firmly and restore power to test.
Clean the sensor: If the probe tip is coated in grease or carbon build-up, clean it gently with a damp cloth (oven cold and unplugged). Retest before replacing anything.
Replace the NTC sensor: If the probe is visibly damaged or cleaning/reseating doesn’t resolve the fault, order a genuine replacement Leisure NTC sensor (match your model number — found on the rating plate inside the door frame). Replacement is a straightforward plug-and-swap job requiring only a screwdriver; no gas or mains wiring is involved.
If F03 persists after a new sensor: The fault has moved to the wiring loom or the PCB. Stop DIY at this point and call a qualified appliance engineer.
📞 When to call a professional
Call a qualified appliance repair engineer if F03 persists after replacing the NTC sensor, as the fault likely lies with the wiring loom or main PCB — both of which require disassembly of the cooker’s electrical internals. When you call, tell the engineer: ‘My Leisure cooker is showing an F03 fault code; I’ve already replaced the NTC temperature sensor and the error persists.’ This saves diagnostic time and money. On gas-electric range cookers, always confirm the engineer is Gas Safe registered.
⚖️ Repair or replace?
An NTC sensor replacement is a low-cost repair (£15–£40 for the part) and well worth doing on any cooker under 8 years old. If the PCB is at fault, a replacement board typically costs £80–£150 fitted — still worth repairing on a cooker aged under 6 years, but marginal beyond that. Leisure range cookers retail from £400–£900 new, so a PCB repair on a cooker over 8 years old may not represent good value; weigh it against the appliance’s overall condition.