LG Microwave Error Code E-42

E-42 on an LG microwave indicates an Easy Clean or PH sensor short error, meaning the control board has detected that both terminals of the humidity sensor are shorted together. This prevents normal operation because the microwave cannot read accurate sensor data. The fault points to the sensor itself, the connecting wiring, or the terminal connector.

No, the microwave will typically not operate while displaying E-42 because the fault prevents normal sensor readings. Attempting to bypass or ignore the error is not advisable, as the sensor is part of the cooking control system. The unit should remain out of service until the short condition is diagnosed and corrected.

Repair costs vary depending on the root cause. Sensor replacement parts typically range from $15 to $60, while a new control board can range from $80 to $200 or more depending on the model. Adding professional labor, total repair costs can range from $100 to $300. In some cases, if the microwave is older or the cost approaches the price of a new unit, replacement may be more economical.

Some causes of E-42 are accessible to a knowledgeable DIYer, such as cleaning contamination off sensor terminals or inspecting the wiring harness for visible damage. However, replacing the sensor or control board requires disassembling the microwave, and the high-voltage capacitor inside can retain a dangerous charge even when unplugged. If you are not experienced with appliance electronics, professional service is strongly recommended.

Unplugging the microwave for a few minutes and restoring power may temporarily clear the error display, but the code will return if the underlying short condition in the sensor circuit still exists. A reset does not repair the shorted terminals or any wiring fault. A proper repair requires physically inspecting and correcting the sensor or wiring problem.