LG Microwave Error Code E-31

E-31 on an LG microwave indicates a Weight Sensor Open Error. The microwave detected that the weight sensor's output value exceeded the maximum readable hexadecimal value of 0xFF for 5 or more consecutive seconds, which the control board interprets as an open or broken circuit in the sensor system. This fault disables weight-based auto-cook functions until the sensor circuit is repaired.

The E-31 error specifically affects the weight sensor circuit, which is used for automatic cooking programs based on food weight. Basic microwave heating functions may still be available, but you should not ignore the fault or attempt to use the appliance if it is behaving erratically. It is best to have the sensor circuit inspected before continued regular use.

Repair costs for an E-31 error vary depending on the root cause. If only a connector needs reseating or cleaning, the cost may be limited to a service call fee, typically in the range of $75 to $150. If the weight sensor requires replacement, parts and labor combined can range from $100 to $250 or more depending on the specific model and local labor rates. If the control board is at fault, costs will be higher.

Some causes of E-31 can be addressed without replacing parts, such as reseating a loose connector or cleaning corroded terminals. However, if the weight sensor itself has failed, it will need to be replaced, which requires disassembling the microwave. Because microwaves contain a high-voltage capacitor that can retain a lethal charge even when unplugged, internal repairs should only be performed by a qualified technician unless you are experienced with high-voltage appliance safety procedures.

A power reset by unplugging the microwave for a few minutes may temporarily clear the error display, but if the underlying weight sensor circuit problem still exists, the E-31 code will return once the control board reads the sensor again. A reset alone does not repair the open circuit condition that triggers the fault.