What the F31 Error Means on a Whirlpool Dryer
The F31 error code on many Whirlpool electric dryers usually points to a temperature-sensing problem in the dryer’s control circuit — most commonly a failed thermistor (temperature sensor) or an open/short in the sensor circuit. When the dryer can’t read temperature correctly it may stop heating, run much longer cycles, or in some cases mismanage heating which could create safety concerns. Users often notice longer drying times, clothes that come out still damp, the dryer cycling on and off oddly, or a non-heating condition. In other situations the control board detects an out-of-range signal from the sensor and throws F31 to protect the machine.
Common Causes
- Failing or open thermistor/temperature sensor
- Damaged or disconnected wiring harness or sensor connector
- Corrosion or poor electrical connection at terminals
- Faulty main control board (incorrectly reading the sensor circuit)
- Blown or stuck high-limit or cycling thermostat
- Heating element issues affecting temperature readings
- Restricted venting or extreme lint buildup causing abnormal temperature behavior
Troubleshooting Steps
- Power safety first: unplug the dryer or flip its breaker before inspecting any internal components.
- Reset the dryer: unplug for 1–5 minutes then restore power to clear temporary faults and retest for the code.
- Check venting and lint trap: clean the lint screen and inspect/clean the vent duct to ensure proper airflow — restricted vents can trigger temperature faults.
- Run diagnostics: consult your model’s service manual to enter the diagnostic mode and verify the F31 event history and live sensor readings if available.
- Inspect wiring and connectors: visually check the thermistor wiring for breaks, pinched wires, damaged insulation, or loose/corroded connectors and reseat them.
- Test the thermistor/temperature sensor: with the dryer disconnected, use a multimeter to measure the sensor’s resistance at room temperature and compare to the specification in the technical sheet. Replace if out of range or if open/shorted.
- Check thermostats and heating element: test high-limit and cycling thermostats for continuity and inspect the heating element for opens that can cause abnormal temperature behavior.
- Swap or test the control board last: if the sensor, wiring, and thermostats test good but the code persists, a failing main control board or its relay circuitry may be the cause — this is typically a later step after component checks.
- After replacement or repair, clear the code and run a test cycle to confirm the fault is resolved. Monitor performance to ensure normal drying times and temperatures.
Maintenance / Prevention Tips
- Clean the lint screen b