Whirlpool Microwave Error Code F4E4

F4E4 means the control board has detected a humidity sensor failure. The humidity sensor monitors steam levels inside the cavity to control automatic cooking features. When the board cannot read a valid signal from the sensor, it logs F4E4 and disables sensor-based cooking modes.

You can typically still run the microwave using manual timed cooking modes, since those do not rely on the humidity sensor. However, any sensor cook, auto-reheat, or moisture-based automatic programs will not function correctly and should not be used until the fault is repaired. Continuing to use sensor-based programs with a failed sensor may result in overcooked or undercooked food.

Press CANCEL twice, then press START to enter Diagnostics mode. Once in diagnostics, press COOK to pull up the humidity sensor reading on the display. A reading of '8891' means the sensor is functioning within the acceptable range. Any other value confirms the sensor or its wiring circuit is faulty and the sensor should be replaced.

Start by entering Diagnostics mode: press CANCEL, CANCEL, then START, then press COOK to display the humidity sensor reading. If the display shows anything other than '8891', the humidity sensor needs to be replaced. Before replacing it, inspect the wiring harness and connector for loose connections or corrosion, since a bad connection can produce the same code. If the wiring is intact and the sensor reading is still wrong, replacing the humidity sensor is the correct fix.

The humidity sensor part itself typically costs between $20 and $60 depending on the model. If you are comfortable disassembling the microwave and working with small electrical connectors, this is a DIY-friendly repair. Professional labor to diagnose and replace the sensor generally adds $75 to $150 in service charges. If the control board is found to be the cause instead, board replacement costs can range from $100 to $250 for the part alone, making professional diagnosis worthwhile before committing to that repair.