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Error code reference

LG Oven Error Code C-30

The PCB temp sensor is open when the oven is operating, or PCB temperature rises abnormally high.

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The PCB temp sensor is open when the oven is operating, or PCB temperature rises abnormally high.

First step from the service manual

Disconnect power. Open back cover. Replace the Main PCB.

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

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What C-30 means on a LG oven

The C-30 error code on an LG oven indicates a fault condition with the PCB (printed circuit board) temperature sensor. This sensor is integrated into the main control board and monitors the temperature of the PCB itself during oven operation. When the sensor circuit reads as open, meaning the sensor or its circuit path has lost continuity, the oven's control system detects an invalid reading and triggers this fault. Alternatively, C-30 can appear when the PCB temperature rises to an abnormally high level, which the sensor does detect but the reading exceeds safe operating thresholds.

The main PCB houses the control circuitry that manages all oven functions, including temperature regulation, timing, and user interface responses. Because the temperature sensor responsible for this fault is embedded within or directly mounted on the main PCB assembly, it cannot be serviced or replaced independently. A failed solder joint on the sensor, a damaged trace, or general board degradation from heat cycling or moisture exposure can all result in an open sensor condition. Overheating of the board itself may stem from blocked ventilation, failed cooling components, or prolonged high-temperature operation.

The diagnostic procedure calls for disconnecting power to the oven before opening the back cover to access the main PCB. Since the sensor is part of the board assembly and not a standalone replaceable component, the corrective action is full replacement of the main PCB. Technicians should inspect the board for visible signs of heat damage, discoloration, or burnt components before installing the replacement, as an underlying ventilation or cooling issue could damage a new board if not resolved first.

Source: manufacturer service documentation.

Common causes of C-30

  1. 01

    Failed PCB temperature sensor circuit

    Part replacement

    The temperature sensor integrated into the main PCB has developed an open circuit, meaning the electrical path is broken and no valid reading can be sent to the control system. This is the most direct cause of C-30 and requires main PCB replacement.

  2. 02

    Main PCB heat damage or degradation

    Part replacement

    Repeated thermal cycling or exposure to excessive heat can degrade solder joints and board traces over time, leading to an open sensor condition. Visible discoloration or burnt spots on the board surface are indicators of this cause.

  3. 03

    Blocked or restricted oven ventilation

    Wiring / connection

    If airflow around the control board is obstructed, the PCB can overheat during normal oven operation, triggering C-30 based on a legitimately high temperature reading. Check the oven's vents and surrounding clearances for blockages before replacing the board.

  4. 04

    Moisture or contamination on the PCB

    Part replacement

    Moisture infiltration or grease contamination on the control board can cause shorts or corrosion that disrupts the sensor circuit. Inspect the board surface for residue, corrosion, or signs of moisture damage.

See the test procedure for each cause

Frequently asked questions about C-30

What does C-30 mean on a LG oven?
C-30 on an LG oven indicates a problem with the PCB temperature sensor on the main control board. The sensor is either reading as an open circuit, meaning it has lost continuity, or it is detecting that the PCB temperature has risen to an abnormally high level. In either case, the oven stops normal operation to prevent further damage. Resolving this fault requires replacing the main PCB.
Can I fix a C-30 error on my LG oven myself?
The repair requires disconnecting power, removing the back cover, and replacing the main PCB. A technician with basic appliance repair experience can perform this task, but it does involve working inside the oven's electrical enclosure. Always disconnect power completely before opening the unit. If you are not comfortable working with appliance electronics, a qualified technician should handle the repair.
Is it safe to use my LG oven while it shows a C-30 error?
No, you should not continue operating the oven while C-30 is active. The error indicates either a non-functional PCB temperature sensor or actual overheating of the control board. Running the oven under these conditions could cause further damage to the control electronics or create a safety risk. Disconnect power and have the unit serviced before using it again.
Will resetting my LG oven clear the C-30 error?
Disconnecting power and restoring it may temporarily clear the displayed code, but C-30 will return if the underlying issue with the PCB temperature sensor has not been resolved. A simple reset does not repair an open sensor circuit or address board overheating. The fault will reappear once the oven resumes operation and the control system re-checks the sensor status.
How much does it cost to repair a C-30 error on an LG oven?
The main cost involved is the replacement main PCB, with parts typically ranging from $150 to $400 depending on the specific LG oven model. If a professional technician performs the repair, labor costs will add to the total, generally bringing the full repair cost to a range of $250 to $600 or more. Obtaining a parts quote for your specific model number before committing to the repair is recommended, especially on older units where the repair cost may approach replacement value.

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