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Error code reference

LG Range Error Code FD

Probe failure

LG codesLG range codes

Probe failure - shorted probe.

First step from the service manual

Check meat probe resistance (56K ohms at room temperature at CN2 pins 1 to 2 with CN2 disconnected from board).

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

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What FD means on a LG range

The FD error code on an LG range indicates a shorted meat probe condition. The meat probe is a temperature-sensing accessory that plugs into a dedicated jack on the range, allowing the oven to monitor the internal temperature of food during cooking. The probe uses a thermistor circuit, and the control board reads the resistance value across the thermistor to calculate temperature. When that resistance drops far below the expected value due to a short circuit in the probe or its wiring, the board interprets the reading as an out-of-range fault and displays FD.

The first diagnostic step is to disconnect the probe connector at CN2 on the control board and measure resistance across pins 1 and 2. A properly functioning probe should read approximately 56K ohms at room temperature. A shorted probe will read significantly lower, often near zero ohms, because the internal thermistor element or the wiring has developed an electrical short, collapsing the resistance to near zero and causing the board to flag the failure.

Common causes include physical damage to the probe cable such as pinching, burning, or kinking near the oven cavity, as well as moisture or grease contamination inside the probe connector. In some cases the probe jack receptacle inside the oven can corrode or develop an internal short. If the probe and its cable test within spec, the fault may point to a failing control board that is misreading the CN2 input circuit, though this is less common.

Source: manufacturer service documentation.

Common causes of FD

  1. 01

    Damaged or shorted meat probe

    Part replacement

    The thermistor element inside the probe itself has failed, causing the resistance to drop far below the expected 56K ohms at room temperature. This is the most common cause and is confirmed by measuring resistance across CN2 pins 1 and 2 with the connector unplugged from the board.

  2. 02

    Damaged probe cable

    Part replacement

    The cable connecting the probe to the oven jack may be pinched, melted, or kinked, especially near the oven door or cavity entry point. A damaged cable can create a short circuit even if the probe tip itself is intact.

  3. 03

    Contaminated probe connector or jack

    Wiring / connection

    Grease, moisture, or food debris inside the probe connector or the wall jack can create a conductive path that mimics a short circuit. Inspect the connector and jack for visible contamination and clean thoroughly before retesting resistance.

  4. 04

    Corroded or damaged probe jack receptacle

    Part replacement

    The probe receptacle mounted inside the oven cavity can corrode or develop internal damage over time, causing a short between the circuit pins independent of the probe itself. If the fault clears when the probe is removed but persists at the CN2 connector, the jack may need replacement.

  5. 05

    Faulty control board CN2 input circuit

    Part replacement

    If the probe and all wiring test at the correct 56K ohm resistance but the FD code persists, the control board may have a failed input circuit on the CN2 connector pins. This is the least common cause and is typically diagnosed after all other components have been ruled out.

See the test procedure for each cause

Frequently asked questions about FD

What does FD mean on a LG range?
The FD code on an LG range indicates a shorted meat probe. The control board monitors the resistance of the probe thermistor at the CN2 connector, and when that resistance is far below the expected 56K ohms at room temperature, it flags a short circuit fault. The probe, its cable, or the probe jack are the most likely sources of the problem.
Can I fix the FD error code myself?
In many cases, yes. Start by unplugging the probe and checking whether the error clears. If it does, measure the probe resistance with a multimeter at the CN2 connector pins to confirm whether the probe is shorted. A damaged probe is a straightforward part swap that most DIYers can handle without specialized tools.
Is it safe to use my LG oven while the FD code is showing?
You can generally use the oven for standard baking and broiling functions without the probe inserted, as the FD code specifically relates to the meat probe circuit. However, you should not attempt to use the probe-assisted cooking mode until the fault is resolved, as the oven will not be able to accurately monitor food temperature.
Will resetting the oven clear the FD error code?
Resetting the oven by cutting power at the breaker may temporarily clear the display, but the FD code will return as soon as the control board detects the shorted probe circuit again. A reset does not fix the underlying fault. The probe, cable, or jack must be inspected and repaired or replaced to resolve the error permanently.
How much does it cost to fix the FD error code on an LG range?
If only the meat probe needs replacement, the part typically costs in the range of $20 to $60 depending on the model, making it one of the more affordable repairs. If the control board is at fault, board replacement can run anywhere from $150 to $350 or more for parts alone. A professional diagnostic service call will add labor costs on top of any parts needed.

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