LG Oven Error Code F-6

The F-6 error code on an LG oven indicates that the upper oven cavity temperature has exceeded 650°F (343°C) continuously for at least two minutes during a cooking cycle. This threshold is well above normal baking and broiling operating temperatures, signaling a runaway heating condition. The control system monitors temperature through a sensor circuit and triggers this fault when the overtemperature condition persists beyond the two-minute window, cutting off normal operation to prevent damage or a fire hazard.

The root cause is almost always a welded or shorted relay on the relay PCB rather than a faulty temperature sensor. The relay PCB controls power delivery to the upper oven heating elements through a series of heater relays. When a relay contact welds shut due to arcing or excessive current, it can no longer open to interrupt power to the element. The bake or broil element stays energized continuously regardless of the control board's commands, causing the oven temperature to climb unchecked until the F-6 fault is triggered.

Diagnosing this fault begins with disconnecting power to the appliance and removing the relay PCB harness. The key test points are L1 at TAB1 pin 18 and TAB6 pin 20, along with all heater relay contacts on the board. Using a multimeter set to continuity or resistance, each relay should measure infinite resistance (open circuit) when de-energized. Any relay that shows continuity or low resistance in its de-energized state has welded contacts and must be treated as the likely cause of the sustained overtemperature condition.