Safety first: Unplug the washer and allow it to cool before working near the heater.

F03 indicates a problem with the temperature sensing circuit.

Locate the NTC sensor: Remove the rear panel. The NTC is usually mounted in the heater housing at the bottom of the tub with two small wires.
Check connections: Ensure the NTC plug is fully seated and free of corrosion or moisture. Clean and reseat if necessary.
Resistance test (for users with a multimeter): Disconnect the NTC plug. Measure resistance across the sensor. At room temperature (20–25°C), it is typically around 20 kΩ (varies by model). If it reads open circuit or near 0 Ω, replace the NTC sensor.
Inspect wiring: Trace the NTC wires back to the control board. Look for cuts, burns, or loose connectors. Repair any damage with proper connectors and insulation.
Control board: If the NTC tests good and wiring is intact but F03 persists, the temperature circuit on the control board may be faulty and the board will need replacement.
Reassemble and test: Refit panels, restore power, and run a 40°C wash to confirm normal heating and no error.

Washer stops mid-cycle, may not heat water, and displays F03; sometimes cycle ends quickly with cold water.

Possible Causes