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Error code reference

LG Oven Error Code F-16

Lower oven temperature is over 650°F/343°C continuously during 2 minutes while cooking.

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Lower oven temperature is over 650°F/343°C continuously during 2 minutes while cooking.

First step from the service manual

Disconnect power, remove relay PCB harness, check L1 and all heater relays for welding; normal relay should show infinite resistance (not welded).

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What F-16 means on a LG oven

The F-16 error code on an LG oven indicates that the lower oven cavity temperature has exceeded 650°F (343°C) and remained above that threshold continuously for two minutes during a cooking cycle. This is a thermal runaway condition, meaning the oven's heating system is no longer being controlled properly by the relay PCB. Under normal operation, the control board cycles the bake or broil elements on and off to maintain the target temperature. When a relay on the PCB welds shut, it loses the ability to interrupt current flow to the heating element, causing the element to run continuously without shutoff.

The relay PCB contains multiple relays that govern the lower oven heating elements as well as the L1 line connection. If any of these relays weld closed due to excessive current, heat, or age-related contact degradation, the circuit remains energized regardless of what the control board commands. A properly functioning relay will show infinite resistance across its contacts when open. A welded relay will show continuity or near-zero resistance even when it should be open, confirming the failure. Diagnosis requires disconnecting power to the unit, removing the relay PCB harness, and individually testing L1 and all heater relay contacts with a multimeter.

Beyond a welded relay, a faulty oven temperature sensor can also contribute to this fault if it is sending incorrect low-temperature readings to the control board, causing the board to keep the heating circuit active longer than intended. However, the primary and most common cause of F-16 is relay contact welding on the relay PCB, which is a hardware failure requiring physical component replacement rather than a simple reset or recalibration.

Source: manufacturer service documentation.

Common causes of F-16

  1. 01

    Welded Heater Relay on Relay PCB

    Part replacement

    One or more heater relay contacts on the relay PCB have fused shut, keeping the lower heating element energized continuously. Testing with a multimeter across the relay contacts while the harness is disconnected will show near-zero resistance instead of infinite resistance if the relay is welded.

  2. 02

    Welded L1 Relay on Relay PCB

    Part replacement

    The L1 line relay on the relay PCB can also weld closed, sending uninterrupted power to the lower oven circuit regardless of the control board's commands. This is tested the same way as the heater relays, by checking for infinite resistance across the open relay contacts.

  3. 03

    Faulty Oven Temperature Sensor

    Part replacement

    A defective lower oven temperature sensor may report inaccurately low temperatures to the control board, causing the board to continue calling for heat even when the cavity has reached dangerously high temperatures. Resistance testing of the sensor at room temperature can help identify a sensor reading outside its normal range.

  4. 04

    Failed Relay PCB

    Part replacement

    If individual relay testing does not isolate a single welded contact, the relay PCB itself may have broader internal damage affecting its ability to properly switch heating circuits. Replacing the entire relay PCB is required in this case.

See the test procedure for each cause

Frequently asked questions about F-16

What does F-16 mean on a LG oven?
F-16 on an LG oven means the lower oven temperature exceeded 650°F (343°C) and stayed above that level for two continuous minutes during cooking. This indicates a loss of temperature control, most commonly caused by a relay on the relay PCB welding shut and holding the heating element on without interruption. The oven triggers this code as a protective measure to alert you that the heating circuit is not functioning safely.
Can I fix the F-16 error myself?
A knowledgeable DIYer can perform the initial diagnosis by disconnecting power, removing the relay PCB harness, and using a multimeter to check each relay contact for infinite resistance. If a welded relay or faulty temperature sensor is identified, those parts can be replaced. However, working with oven electrical components carries risk, and if you are not comfortable with electrical testing or component replacement, a qualified technician is the safer option.
Is it safe to use my LG oven while the F-16 code is showing?
No, you should not use the oven while this error is active. The F-16 code indicates that the lower oven may be losing temperature regulation, meaning the heating element could run without shutoff. Continuing to operate the oven in this condition poses a serious risk of overheating, property damage, or fire.
Will resetting my LG oven clear the F-16 error?
Disconnecting power may temporarily clear the error display, but the underlying fault will remain. If a relay is physically welded shut, restoring power will cause the same thermal runaway condition to repeat and the code will return. The root cause, typically a welded relay or failed relay PCB, must be repaired before the oven will operate safely and without the error returning.
How much does it cost to repair the F-16 error on an LG oven?
Repair costs depend on which component has failed. A replacement relay PCB typically ranges from around $80 to $200 or more for parts, while a temperature sensor is generally less expensive in comparison. Adding professional labor charges, a total repair can range from roughly $150 to $400 or higher depending on your location and the specific parts required.

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