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Error code reference

LG Microwave Error Code C-2

Temperature sensor open or short information code

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Temperature sensor open or short information code: when temperature sensor value is below or more than threshold, marks C-2 and 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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What C-2 means on a LG microwave

The C-2 error code on an LG microwave indicates a fault with the cavity temperature sensor, also called a thermistor. This sensor monitors the internal temperature of the microwave cavity during operation. When the sensor's output value falls below or rises above the acceptable threshold range, the control board registers the condition as an open circuit or short circuit in the sensor circuit. An open circuit means the electrical path through the sensor is broken entirely, producing a resistance reading outside the upper limit. A short circuit means the sensor's resistance has collapsed, pushing the reading below the lower threshold. Either condition causes the unit to immediately enter cancel mode, halting the cooking cycle as a protective measure.

The temperature sensor is a negative temperature coefficient (NTC) thermistor or a similar resistive element positioned inside the microwave cavity. Its resistance changes predictably with temperature, and the PCB interprets those resistance values to determine cavity temperature. When the sensor reads out of range, the board cannot confirm safe operating conditions, so it disables the cooking function. This is an intentional safety response built into the control logic.

Common causes include a failed sensor element, a damaged wiring harness between the sensor housing and the PCB connector, or a loose or corroded connector at either end. Physical damage from arcing inside the cavity can also affect the sensor or its wiring. Diagnosis should begin with a visual inspection of the sensor housing and all connector points, followed by a resistance check of the sensor element itself to confirm whether it is open, shorted, or within specification.

Source: manufacturer service documentation.

Common causes of C-2

  1. 01

    Failed temperature sensor

    Part replacement

    The thermistor element inside the sensor housing has failed open or shorted internally, producing a resistance value outside the acceptable range. The sensor will need to be tested with a multimeter and replaced if the reading is out of specification.

  2. 02

    Loose or disconnected connector at the PCB

    Wiring / connection

    The connector that links the sensor wiring harness to the main control board may have worked loose over time or through vibration. Inspect the PCB connector seat and reseat the connector firmly to see if the error clears.

  3. 03

    Damaged wiring harness

    Part replacement

    The wiring between the sensor housing and the PCB may have a break, pinch, or burn that interrupts the circuit. Visually trace the harness for any signs of damage and test continuity through each wire.

  4. 04

    Corroded or oxidized connector terminals

    Wiring / connection

    Moisture or heat exposure inside the cavity can cause the sensor connector terminals to corrode, increasing resistance in the circuit to the point where the board interprets it as an open fault. Inspect the terminals for discoloration or buildup and clean or replace as needed.

  5. 05

    Arcing damage inside the cavity

    Part replacement

    Arcing events from improper use, such as metallic items placed inside the microwave, can physically damage the sensor housing or its nearby wiring. Look for scorch marks near the sensor location as a sign of this type of damage.

See the test procedure for each cause

Frequently asked questions about C-2

What does C-2 mean on a LG microwave?
The C-2 code on an LG microwave means the cavity temperature sensor is reading a value outside the acceptable threshold, indicating either an open circuit or a short circuit in the sensor or its wiring. When this condition is detected, the microwave automatically cancels the current cooking operation and enters cancel mode. The fault is tied specifically to the temperature sensor circuit, which includes the sensor itself, the wiring harness, and the connector at the control board.
Can I fix the C-2 error on my LG microwave myself?
Some causes of the C-2 error, such as a loose connector at the PCB, can be addressed by a knowledgeable DIYer after unplugging the unit and allowing the high-voltage capacitor to discharge safely. However, working inside a microwave involves serious electrical hazards, including capacitors that can store a lethal charge even after the unit is unplugged. If you are not experienced with appliance repair and safe capacitor discharge procedures, the repair should be performed by a qualified technician.
Is it safe to keep using my LG microwave when C-2 appears?
No. When C-2 appears, the microwave enters cancel mode and stops cooking because the control board cannot confirm safe temperature conditions inside the cavity. Attempting to bypass or ignore this error is not recommended, as the temperature sensor is a protective component. The unit should remain unplugged until the fault is diagnosed and resolved.
Will resetting my LG microwave clear the C-2 error code?
A power reset, such as unplugging the unit for a few minutes, may temporarily clear the display, but the C-2 code will return if the underlying fault in the temperature sensor circuit has not been corrected. Because the code triggers when the sensor reading falls outside its threshold, any ongoing hardware problem with the sensor or its wiring will cause the error to reappear as soon as the microwave attempts to operate.
How much does it cost to repair a C-2 error on an LG microwave?
Repair costs depend on what component has failed. A replacement temperature sensor part alone typically costs in the range of $15 to $50 depending on the specific model. If a professional technician is needed, labor charges will add to that cost, with total repair estimates commonly ranging from $80 to $200. If the control board or wiring harness is also damaged, costs will be at the higher end of that range or beyond.

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