LG Microwave Error Code E-B3

The E-B3 code on an LG microwave indicates a humidity sensor maximum time error. The humidity sensor, which detects steam levels during cooking to help regulate cook time, exceeded the maximum allowed operating duration without completing its cycle. The microwave stops cooking and displays this code to alert you that the sensor circuit needs to be inspected.

You should not continue using the microwave while the E-B3 error is active. The fault indicates the humidity sensor is not functioning correctly, which means the microwave may not properly regulate cooking cycles. Operating the unit in this condition could lead to overcooking, unpredictable behavior, or further component damage.

Unplugging the microwave for a few minutes and restoring power may temporarily clear the E-B3 code, but if the underlying cause such as a faulty sensor or wiring issue is not resolved, the error will return during the next cooking cycle that uses the humidity sensor function. A reset alone is not a fix and should only be used as part of the diagnostic process.

Some causes of E-B3 are DIY-friendly, such as cleaning a contaminated sensor surface or reseating a loose wiring connector at the sensor. However, replacing the humidity sensor or the control board involves working inside the microwave cabinet, which requires discharging the high-voltage capacitor before any work begins. If you are not comfortable with high-voltage appliance repair, a qualified technician should perform the repair.

Repair costs vary depending on the faulty component. A replacement humidity sensor typically ranges from around 20 to 60 dollars for the part, while a control board can range from 80 to 200 dollars or more. Adding professional labor costs, a full repair visit may run anywhere from 100 to 300 dollars depending on your location and the parts required.