F4
Whirlpool Washing Machine
Severity: ModerateWhat Does This Error Mean?
The F4 error means your Whirlpool washer's water temperature sensor (NTC thermistor) has a short circuit. The sensor is sending an invalid reading — either reading zero resistance or no signal at all. The washer cannot monitor water temperature correctly and stops the cycle. This usually means the sensor itself has failed and needs replacing.
Affected Models
- WFW5620HW
- WFW9620HC
- WFW8620HC
- WFW6620HW
- Whirlpool front-load washers
Common Causes
- Failed NTC thermistor with a short circuit in the sensor element
- Damaged wiring harness connecting the thermistor to the control board
- Water damage or corrosion on the thermistor connector
- Thermistor has been exposed to excessively high temperatures and burned out
- Control board fault causing incorrect resistance readings from the sensor circuit
How to Fix It
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Cancel the cycle and unplug the washer for 10 minutes.
A full power reset can clear a false F4 caused by a temporary electrical spike. This is worth trying before purchasing parts.
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Plug the washer back in and run a cold water cycle to test.
A cold cycle doesn't rely as heavily on the thermistor for temperature control. If it completes normally, the thermistor is the likely culprit — it only fails under heat conditions.
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Try a hot wash cycle and watch for the F4 error.
If F4 returns only on hot or warm cycles, the thermistor is confirmed as the issue. It's reading a short circuit when it heats up.
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Do not repeatedly restart the machine with a sensor error.
Running the washer without a working temperature sensor means the heater may run unchecked. This could cause overheating, which is a safety concern.
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Have the thermistor tested and replaced by a technician.
The thermistor is a small, inexpensive part — typically $10–$30. Labor is the main cost. A technician can confirm the fault with a multimeter reading before ordering the part.
When to Call a Professional
Thermistor replacement requires accessing the inside of the washer near the drum. If a reset doesn't clear F4, a technician should test the sensor with a multimeter. A licensed appliance technician can replace the thermistor quickly. Expect repair costs of $100–$200 including the part and labor.
Frequently Asked Questions
What is an NTC thermistor in a washing machine?
NTC stands for Negative Temperature Coefficient. It's a type of resistor whose electrical resistance changes with temperature. As water heats up, the thermistor's resistance drops in a predictable way. The control board reads this resistance to determine the exact water temperature. A shorted thermistor sends a resistance reading of near zero — which is impossible — so the board shows F4.
How can I test the thermistor myself?
You need a basic multimeter set to resistance (Ohms) mode. Disconnect the thermistor and measure its resistance at room temperature. A working NTC thermistor typically reads around 10,000–50,000 ohms depending on the model. A reading of zero or near-zero confirms a short circuit. Check your model's service manual for the expected resistance value.
Is the F4 washer error the same as the F4 dishwasher error?
No — Whirlpool uses similar F-codes across different appliance types, but they don't mean the same thing. For the washer, F4 is a temperature sensor short circuit. For the dishwasher, F4 means a drain pump problem. Always confirm which appliance you're troubleshooting before following fix steps.