Whirlpool · Washing Machine
Whirlpool Washing Machine F31 Error Code
Motor control unit overheated
What this error means
F31 appears when the Motor Control Unit heat sink exceeds its safe temperature and shuts down the drive motor. After four consecutive heat trips the code latches on the display until the MCU cools or is replaced.
How F31 is detected
When F31 appears on a Whirlpool washing machine, the control board has confirmed that water did not leave the machine within the programmed drain window. On Whirlpool WFW9150FW, Whirlpool WFW9620HW, and similar variants, the drain pump runs for a fixed interval—often three to seven minutes on washers and dishwashers—while a pressure switch or turbidity sensor verifies the tub or sump is empty. If water remains, the cycle stops to prevent spin with a full tub or overflow on the next fill.
Most F31 calls are resolved without parts: unplug the washer for 30 minutes to let the mcu heat sink cool. Restricted drain paths mimic pump failure because the impeller spins against a blocked hose or filter. Document whether the pump hums audibly during the drain step; a humming pump with no water movement points to a clogged filter or kinked hose, while silence may indicate a failed pump motor or loose wiring at the harness.
After clearing blockages, run a short cycle and listen at the drain hose for steady water flow. If F31 returns on the next load with a clean filter and straight hose, measure resistance at the pump motor connector per the service manual for your model before ordering a replacement pump assembly.
Common causes
- Overloaded drum binding the motor during ramp-up
- Failed MCU heat sink thermal interface or clogged airflow
- Shorted motor windings drawing excessive current
- Restricted rear-panel ventilation from pushed-in installation
Step-by-step fixes
- 1Unplug the washer for 30 minutes to let the MCU heat sink cool
- 2Reduce load size and redistribute heavy items evenly before retrying
- 3Pull the washer forward to ensure at least one inch of rear clearance for airflow
- 4Rotate the drum by hand with the door open—it should turn with slight resistance only
When to call a technician
Repeated F31 on light loads after cooling indicates a failing MCU or drive motor needing professional diagnosis.
Affected models
- Whirlpool WFW9150FW
- Whirlpool WFW9620HW
- Whirlpool WFW8620HC
Prevention & maintenance
- Clean drain filters and hose terminations monthly on high-use washing machines to prevent F31 from lint and food debris buildup.
- Record when F31 appears in the cycle and whether it clears after a 60-second power reset on your Whirlpool washing machine—that detail speeds diagnosis if you call service.
- Keep the model and serial number from the rating plate when ordering parts for F31; Whirlpool uses multiple revisions with different harness lengths and board firmware.
- Photograph wiring connector orientation before disconnecting any component while troubleshooting F31; reversed plugs on pumps and valves cause immediate repeat faults.