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Error code reference

Samsung Air Conditioner Error Code 312

Main cooling solenoid valve open error.

Samsung codesSamsung air conditioner codes

Main cooling solenoid valve open error.

First step from the service manual

Check if main cooling solenoid valve is open; check if there is any problem with valve connector/coil setting.

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 312 means on a Samsung air conditioner

Error code 312 on a Samsung air conditioner indicates a main cooling solenoid valve open error. This fault is detected when the control board determines that the main cooling solenoid valve is in an open state when it should not be, or that the valve is failing to respond correctly to control signals. The solenoid valve is a critical component in the refrigerant circuit, responsible for regulating refrigerant flow through the system. When this valve malfunctions or loses proper electrical continuity, the unit cannot manage refrigerant distribution correctly, leading to cooling failure and the error condition.

The most common points of failure associated with this code are the valve connector and the solenoid coil itself. A loose, corroded, or damaged connector at the valve can interrupt the electrical signal needed to actuate the valve, causing the controller to register an open circuit or unresponsive component. Similarly, a failed solenoid coil, which has either opened internally or developed a short, will prevent the valve from operating and trigger this fault code.

Diagnosis should begin by physically inspecting the main cooling solenoid valve and its associated wiring harness. Verify the connector is fully seated and free of corrosion or damage. The coil can be tested for continuity and resistance using a multimeter; an open coil will show infinite resistance, confirming coil failure. If wiring and connections check out but the fault persists, the solenoid valve assembly itself may need to be replaced.

Source: manufacturer service documentation.

Common causes of 312

  1. 01

    Loose or damaged valve connector

    Wiring / connection

    The electrical connector at the solenoid valve may have become loose, corroded, or damaged, interrupting the control signal. Inspect the connector for proper seating, bent pins, or signs of corrosion or heat damage.

  2. 02

    Failed solenoid coil

    Part replacement

    The solenoid coil can fail internally by opening or shorting, leaving the valve unresponsive to control signals. Test the coil with a multimeter; an open coil will read infinite resistance and requires coil or valve replacement.

  3. 03

    Solenoid valve stuck in open position

    Part replacement

    The mechanical valve itself may be stuck open due to debris, wear, or internal failure, causing the controller to detect an abnormal operating state. This typically requires valve replacement.

  4. 04

    Damaged wiring harness

    Wiring / connection

    Wiring between the control board and the solenoid valve can become chafed, pinched, or broken, causing an open circuit condition. Trace the wiring along its full path and check for visible damage or breaks.

  5. 05

    Control board output fault

    Part replacement

    If the control board is not supplying the correct voltage signal to the solenoid valve, the valve cannot operate and the error will be triggered. This should be investigated only after ruling out all wiring and valve component issues.

See the test procedure for each cause

Frequently asked questions about 312

What does 312 mean on a Samsung air conditioner?
Error code 312 on a Samsung air conditioner indicates a main cooling solenoid valve open error. The system has detected that the solenoid valve responsible for controlling refrigerant flow is either stuck open or is not responding correctly to control signals. This prevents the unit from regulating refrigerant distribution, resulting in a loss of cooling performance. The fault is typically related to the valve connector, the solenoid coil, or the wiring connecting them.
Can I fix error code 312 on my Samsung air conditioner myself?
Some basic checks, such as inspecting the solenoid valve connector for looseness or corrosion, are within reach for a knowledgeable DIYer. However, testing the solenoid coil with a multimeter and replacing the valve or its coil involves working near the refrigerant circuit, which requires EPA 608 certification for refrigerant handling in the United States. It is recommended to have a qualified HVAC technician perform any repairs beyond visual inspection.
Is it safe to keep running my air conditioner with error code 312 active?
Running the unit with an active 312 error is not advisable. A malfunctioning main cooling solenoid valve can lead to improper refrigerant flow, which may cause the compressor to operate under abnormal conditions and risk additional component damage. It is best to shut the system down and have it inspected promptly.
Will resetting my Samsung air conditioner clear error code 312?
A simple power reset may temporarily clear the fault display, but if the underlying problem with the solenoid valve, its connector, or its coil has not been resolved, the error code 312 will return when the system attempts to operate. The root cause must be diagnosed and repaired to permanently clear this fault.
How much does it cost to repair error code 312 on a Samsung air conditioner?
Repair costs vary depending on what is faulty. If only the connector or wiring needs attention, labor costs may be relatively low, typically in the range of $75 to $150 for a service call. If the solenoid coil or full valve assembly requires replacement, parts and labor combined can range from $150 to $400 or more depending on the unit model and local labor rates.

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