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Error code reference

LG Microwave Error Code C-10

Cooking (gas) sensor information code; gas sensor value is below 5 or more than 250, unit converts to cancel…

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Cooking (gas) sensor information code; gas sensor value is below 5 or more than 250, unit converts to cancel mode.

First step from the service manual

Check sensor part and connection of sensor housing and PCB's connector.

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

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What C-10 means on a LG microwave

The C-10 code on an LG microwave is an information code related to the cooking gas sensor system. This sensor monitors combustion or gas-related byproducts during cooking cycles, and the unit uses its readings to assist with automatic cooking functions. When the gas sensor's output value falls below 5 or rises above 250, the microwave's control board determines the reading is outside the acceptable operating range and automatically converts the unit to cancel mode, halting the cooking cycle to prevent inaccurate or unsafe operation.

The root cause is typically a fault in the gas sensor itself or a connectivity issue between the sensor and the PCB. The sensor housing connector is a common failure point, as loose, corroded, or damaged pins can cause the signal to drop out entirely or spike beyond normal limits. A fully failed sensor will often produce a reading of zero, triggering the below-5 threshold, while electrical noise or a short can push the value over 250.

Diagnostic work should begin with a physical inspection of the sensor housing and the wiring harness that connects it to the main PCB connector. Check for any visible damage, moisture intrusion, or loose connector seating. If the connector checks out, the sensor component itself should be tested or replaced, as internal sensor degradation over time can cause it to output values outside the 5 to 250 acceptable range even when connections appear intact.

Source: manufacturer service documentation.

Common causes of C-10

  1. 01

    Loose or disconnected sensor connector

    Wiring / connection

    The connector between the gas sensor housing and the main PCB may have come loose or partially disconnected, causing the sensor signal to drop out and fall below the minimum threshold of 5. Inspect the connector for secure seating and any signs of looseness.

  2. 02

    Failed or degraded gas sensor

    Part replacement

    The gas sensor itself may have failed internally, causing it to output a value below 5 or above 250. A sensor that reads consistently at zero or at an extreme high value after confirming good connections is likely defective and needs replacement.

  3. 03

    Corroded or damaged connector pins

    Wiring / connection

    Moisture or heat exposure inside the microwave cavity can corrode the connector pins at the sensor housing or the PCB connector, creating a poor electrical contact that produces out-of-range readings. Look for discoloration, oxidation, or bent pins at both connector ends.

  4. 04

    Damaged wiring harness between sensor and PCB

    Part replacement

    The wiring between the gas sensor and the control board may be pinched, frayed, or broken, interrupting the signal. Trace the harness visually and check for any areas where insulation is worn or wires are kinked near mounting points.

  5. 05

    Faulty main PCB

    Part replacement

    If the sensor and all wiring connections test as intact but the C-10 code persists, the main PCB may be misreading or failing to properly process the sensor signal. This is the least common cause and should only be considered after ruling out sensor and wiring issues.

See the test procedure for each cause

Frequently asked questions about C-10

What does C-10 mean on a LG microwave?
C-10 is a cooking gas sensor information code. It indicates that the gas sensor's output value has gone below 5 or above 250, which is outside the acceptable operating range. When this happens, the microwave automatically cancels the cooking cycle. The issue points to a problem with the sensor itself, its connector, or the wiring connecting it to the control board.
Can I fix the C-10 error myself on my LG microwave?
A DIYer with some appliance repair experience can start by checking the sensor connector and wiring harness for loose connections, corrosion, or visible damage, and reseating the connector may resolve the code if that is the cause. However, working inside a microwave involves high-voltage components, particularly the capacitor, which can retain a dangerous charge even when unplugged. If you are not experienced with safely discharging microwave capacitors, it is best to have a qualified technician perform the diagnosis and repair.
Is it safe to use my LG microwave while it shows C-10?
No, you should not attempt to bypass or ignore the C-10 code and continue cooking. The microwave enters cancel mode automatically because the sensor reading is outside a safe and accurate range. Using the unit in this state means the cooking sensor is not functioning correctly, which could result in inaccurate cooking or unmonitored conditions. Address the fault before resuming use.
Will resetting my LG microwave clear the C-10 error?
A reset by unplugging the unit or cutting power may temporarily clear the code display, but the C-10 error will return as soon as a cooking cycle is attempted if the underlying sensor or connection fault has not been corrected. A reset does not repair a failed sensor or fix a loose connector. The physical cause must be diagnosed and resolved first.
How much does it cost to repair a C-10 error on an LG microwave?
If only the sensor connector needs reseating or cleaning, the repair cost may be minimal, covering just a service call fee in the range of $75 to $150. If the gas sensor component itself needs replacement, parts plus labor typically bring the total into the $100 to $250 range depending on your location and the technician's rates. A main PCB replacement, if required, would be the most expensive outcome and could run $150 to $350 or more, at which point comparing the cost to a replacement microwave is worth considering.

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