LG Range Error Code F-8

F-8 on an LG range means the upper oven temperature probe thermistor has been detected in a shorted condition for more than one minute after a cook cycle starts. The oven control board monitors the thermistor's resistance to track oven temperature, and a short causes the resistance to read abnormally low. The oven displays F-8 and stops operation to prevent cooking without reliable temperature feedback. The most likely causes are a failed temperature probe or damaged wiring in the thermistor circuit.

It is not advisable to continue using the upper oven while F-8 is active. The error indicates the oven has no reliable temperature data from its upper probe, meaning the control board cannot properly regulate heat. Operating the oven in this condition risks overheating. Address the fault before using the upper oven again.

If the repair requires only a new upper oven temperature probe, parts typically range from around 20 dollars to 60 dollars depending on the specific model, and the repair is straightforward. If wiring harness repair or control board replacement is needed, total repair costs including labor can range from roughly 150 dollars to 350 dollars or more. Getting a diagnostic from a certified technician first can help narrow down exactly which component needs to be replaced before committing to parts costs.

A knowledgeable DIYer can diagnose and resolve F-8 by testing the upper oven temperature probe with a multimeter and inspecting the wiring harness for visible damage. If the probe tests as shorted, it can typically be replaced by removing a couple of mounting screws inside the oven cavity and unplugging the harness connector. However, if the control board is involved, or if working around oven wiring is unfamiliar territory, a qualified appliance technician is the safer option.

Resetting the range by cycling the power at the breaker may temporarily clear the F-8 display, but the code will return as soon as the oven runs for more than one minute if the underlying fault is still present. The shorted thermistor condition is hardware-based, so a reset alone will not resolve the problem. A proper repair requires diagnosing and correcting the fault in the thermistor probe or its wiring circuit.