What this error means
Heating fault — the dishwasher is not reaching or maintaining the correct wash temperature
The F03 error means the dishwasher has failed to heat the water to the required temperature within the allowed time, or the NTC thermistor temperature sensor has returned a reading outside the expected range. The most common causes are a failed heating element, a faulty NTC sensor, or heavy limescale build-up insulating the element. A wiring fault to either component can also produce this code.
What you'll need first
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Step-by-step
Symptoms to look for
- Dishes coming out cold or still greasy after a hot programme
- Interior of the dishwasher feels no warmer than room temperature mid-cycle
- White powdery residue on dishes after washing — detergent not fully dissolving
- F03 displayed partway through a wash or rinse programme
- Cycle runs for significantly longer than the displayed time before faulting
Diagnostic steps
Unplug the dishwasher for 5 minutes to reset the control board fully. Plug back in and run the hottest available programme — typically an Intensive or 70-degree cycle — with no load. After 15 minutes, carefully and briefly open the door a few centimetres. You should be met immediately by a cloud of warm steam. If the interior feels no warmer than room temperature, the element is not heating.
Fill the base of the dishwasher tub with a proprietary dishwasher descaler or add two tablespoons of citric acid powder to the base. Run a full 65-degree empty cycle. Limescale deposits on the element surface act as insulation, preventing heat transfer to the water even when the element is drawing full power. In hard water areas this is the most common cause of gradual heating decline before the element fails completely.
With the dishwasher completely unplugged, remove the lower basket. The heating element is the U-shaped or circular metal bar running across the base of the tub, visible at the bottom of the wash chamber. Inspect its surface for cracks, bright orange corrosion patches, or areas where the coating has burned away.
With the dishwasher unplugged, remove the lower kickplate panel at the front base of the machine (held by one or two screws). The element terminals protrude through the base of the tub and are accessible from underneath with the panel removed. Disconnect the wiring from both terminals. Set a multimeter to resistance (ohms) and touch one probe to each terminal. A healthy dishwasher element typically reads between 20 and 30 ohms. A reading of zero (short circuit) or OL (open circuit) means the element has failed.
The NTC sensor is a small cylindrical or oval component mounted at the side of the tub base or near the sump, connected by two thin wires. With the machine unplugged and the wiring disconnected from the sensor, set a multimeter to resistance and test across the two sensor terminals. At room temperature (approximately 20 degrees Celsius) a healthy NTC thermistor typically reads between 4,000 and 12,000 ohms — the exact value depends on the specific Hotpoint model. An open circuit (OL) reading or a reading of zero indicates the sensor has failed.
With the kickplate panel removed, inspect the wiring loom connecting the element terminals and the NTC sensor to the main wiring harness. Look for burnt insulation, chafed wire where the loom runs near sharp edges, corroded spade connectors, or any connector that is not fully seated. Disconnect and firmly reconnect each connector.
When to call an engineer
- Heating element reads outside 20 to 30 ohms or shows continuity to earth — must be replaced
- NTC thermistor reads open circuit or zero ohms on a multimeter
- Element tests within normal range but machine still does not heat — wiring or control board fault
- Visible orange corrosion, cracking, or burning on the element surface in the tub base
Frequently asked questions
What is the NTC sensor and why does it cause F03?
Can limescale alone cause F03 without the element being broken?
Are dishes still safe after a cycle that triggered F03?
How do I know if it is the element or the sensor that has failed?
🎯 What is likely causing this fault?
⚠️ Estimates based on common faults — not a guaranteed diagnosis. Always verify before ordering parts.
Parts you may need
Enter your model number to filter results to your exact machine
Usually found on a label inside the door frame or on the back panel of the machine.
| Part | Approx. UK Cost | Find it |
|---|---|---|
| Heating element | £30 - £50 | 🛒 Amazon UK → |
| Heating element | £30 - £40 | 🏷️ eBay UK → |
| Temperature Sensor (NTC) | £15 - £20 | 🏷️ eBay UK → |
| Temperature Sensor (NTC) | £15 - £20 | 🛒 Amazon UK → |
ℹ️ Prices are approximate. Always check the part number matches your model before ordering. Not sure of your model number? Find out how to locate it here.