Samsung Microwave Error Code E-31 — Humidity Sensor Error
What this means
The E-31 error code on Samsung microwaves indicates the humidity sensor (steam sensor) is not functioning correctly. This sensor detects moisture levels in the cooking cavity to automatically adjust cooking time in sensor-cook and reheat modes. A faulty sensor can cause the microwave to overcook, undercook, or display E-31 when sensor-cook features are used. Manual cooking modes may still work normally.
Alternate codes: E31
Step-by-step fix
4 stepsClean the humidity sensor
Open the microwave door and locate the humidity sensor — it's typically a small disc or strip on the ceiling of the microwave cavity or inside a vent grille. Clean it gently with a damp soft cloth to remove any food residue, grease, or film that may be coating the sensor surface.
A buildup of food splatter on the sensor is the most common cause of E-31 — cleaning often fixes it immediately.
Power cycle the microwave
Unplug the microwave for two minutes and plug it back in. Run a sensor-cook test (like sensor reheat on a plate of food) to see if the error returns.
If manual modes work fine but sensor modes trigger E-31, the sensor itself is definitely the issue.
Test the sensor
Unplug the microwave. Remove the outer case. Locate the humidity sensor and disconnect its wires from the control board. Check the tech sheet for the expected resistance range. If the sensor reads outside the expected range, replace it.
WARNING: Avoid contact with high-voltage capacitor and transformer components when working inside the microwave.
Replace the humidity sensor
If cleaning doesn't fix the error and the sensor tests out of range, remove the mounting hardware, disconnect the old sensor, and install the replacement. Reassemble the case and run a sensor-cook test to verify.
After replacing the sensor, wipe the interior cavity clean before testing — existing food residue can affect the new sensor's first readings.
When to call a professional
If the humidity sensor has been cleaned and/or replaced but E-31 persists in sensor-cook modes, the control board's sensor circuit may be at fault. A technician can test the board.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
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