LG Microwave Error Code E-27

E-27 on an LG microwave indicates an initial temperature error in microwave (MW) mode, meaning the control board detected an abnormal temperature reading from the cavity sensor when the oven was operating. The unit shuts down to prevent running under inaccurate thermal conditions. The fault points to the temperature sensor, its wiring, or in rarer cases the main control board.

No, you should not continue operating the microwave while E-27 is active. The error means the control system cannot confirm accurate temperature conditions inside the oven cavity during MW mode. Running the unit without reliable temperature monitoring could allow it to overheat, which presents a safety risk. Stop using it until the fault is diagnosed and resolved.

Repair costs vary depending on the faulty component. A replacement cavity temperature sensor is generally an inexpensive part, typically in the range of $10 to $40 for the part alone, while professional labor to diagnose and install it could bring the total to $80 to $150 or more. If the main control board is at fault, parts alone can range from $50 to $200 or higher, making professional repair costs comparable to replacement for older units.

The first step anyone can take is pressing the Cancel key to clear the error and then restarting the microwave. If the error returns, you can inspect the sensor wiring connectors for looseness or corrosion without any special tools. However, testing the sensor for correct resistance output and working inside the cabinet near the high-voltage capacitor requires caution and some technical experience, so less confident DIYers should consider professional service.

Pressing the Cancel key is the recommended first step and may temporarily clear the code. However, if the underlying cause is a faulty sensor or damaged wiring, the error will return the next time MW mode is used. A reset alone is not a repair, only a way to confirm whether the fault is intermittent or persistent.