Indesit Washing Machine F03 Error Code: Temperature Sensing Fault (Wash NTC Sensor)

What the code means

Indesit Service UK's washing machine error code guide lists F03 as "Temperature sensing fault", with the symptom that the machine is not heating on wash or dry settings, and its advice is to call Indesit to book an engineer. Indesit's technical documentation for the WIL10 washer dryer (the French service file, mod. WIL10FR) gives the engineer's definition: F03 means the wash NTC (the temperature sensor in the drum's heating area) has been detected open circuit or short circuit, or the wash heater relay is stuck closed. The file notes the code is flagged when the machine is full of water. Its service steps are to check the contacts of connector J8 on the board, measure the NTC between pins 11 and 12 of the J8 harness connector (about 20 kOhm at an ambient 20 C), check the J8-to-NTC wiring for continuity if the reading is wrong, test the NTC directly, then replace the NTC, and finally replace the board. For contrast, the same Indesit guide lists F08 as a separate heater fault, and on washer dryers F13 is the matching fault for the drying temperature sensor rather than the wash sensor.

Likely causes

• A failed wash temperature sensor (NTC thermistor) that reads open or short circuit (Indesit WIL10 service file)
• A loose, corroded or damaged connection at connector J8 on the main board, or a break in the wiring between J8 and the sensor
• The wash heater relay on the main board stuck closed, which the service file also reports as F03
• A failed main control board, the last step in Indesit's F03 checklist once the sensor and wiring test fine

Safe DIY checks

1. Switch the machine off and unplug it. If water is still in the drum, drain it through the pump filter at the bottom front, with towels and a shallow tray ready.
2. Try a power reset: leave it unplugged for a couple of minutes, plug back in and run a short warm wash. If F03 comes back, the fault is real.
3. If you're comfortable working on appliances: with the machine unplugged, remove the back panel and find the temperature sensor, which on most models is fitted into the heater element at the bottom of the tub. Check its connector is pushed fully home and the wires aren't chafed or burnt.
4. Measure the sensor with a multimeter. Indesit's service file gives about 20 kOhm at 20 C (room temperature). A reading of zero or open circuit means the sensor needs replacing.
5. If the sensor reads correctly, check the wiring back to connector J8 on the main board for continuity and a clean, tight connection.
6. If the sensor and wiring all check out, the board is the likely fault, so book an engineer.

Parts that commonly fix it

Always match the part number to your exact model.

Related codes

• F01 Indesit Washer F01
• F05 Indesit Washer F05
• F06 Indesit Washer F06
• F11 Indesit Washer F11
• F12 Indesit Washer F12

All Indesit codes →

Sources

1. Indesit Service UK: Washing Machine Error Codes (F03 temperature sensing fault; not heating on wash or dry settings; book an engineer)
2. Indesit WIL10 washer dryer technical documentation, French, p.14 (F03 wash NTC open or short circuit, or wash heater relay stuck, flagged with water in the machine; check J8, NTC about 20 kOhm at 20 C between pins 11 and 12, wiring, replace NTC, then board)