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Error code reference

Samsung Air Conditioner Error Code YEL_FLICKER_RED_FLICKER

CT sensor error

Samsung codesSamsung air conditioner codes

CT sensor error

First step from the service manual

Replace outdoor control board

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 YEL_FLICKER_RED_FLICKER means on a Samsung air conditioner

The YEL_FLICKER_RED_FLICKER error code on a Samsung air conditioner indicates a CT sensor error. The CT (current transformer) sensor is a component mounted on the outdoor unit's control board or within the power circuit that monitors the electrical current draw of the compressor and other outdoor components. This sensor provides real-time current data to the control system, allowing the unit to detect abnormal operating conditions such as compressor overload, locked rotor, or phase issues. When the CT sensor fails or sends a signal outside the expected range, the system triggers this fault code.

The error is displayed through a specific LED flash pattern on the outdoor unit, with the yellow LED flickering alongside a red LED flicker sequence. This visual indication points directly to a CT sensor fault rather than a refrigerant, temperature, or communication issue. The CT sensor is typically integrated into or closely associated with the outdoor control board circuitry, which is why the primary diagnostic step involves replacing the outdoor control board rather than a standalone sensor in many cases.

Common causes include a failed CT sensor due to electrical stress or component aging, wiring faults in the sensor circuit, or a defective outdoor control board where the sensor signal is processed. Because the CT sensor and its processing circuitry are often not serviceable as separate components, board replacement is the recommended corrective action when this error is confirmed.

Source: manufacturer service documentation.

Common causes of YEL_FLICKER_RED_FLICKER

  1. 01

    Failed outdoor control board with integrated CT sensor

    Part replacement

    The CT sensor is part of or directly tied to the outdoor control board. A failed board can produce incorrect or absent current readings, triggering this error. Replacing the outdoor control board is the primary diagnostic and corrective step.

  2. 02

    CT sensor component failure

    Part replacement

    The current transformer sensor itself can fail due to electrical stress, age, or power surges. This causes the sensor output signal to fall outside the expected range, which the control system interprets as a fault.

  3. 03

    Wiring fault in the CT sensor circuit

    Wiring / connection

    Loose, corroded, or damaged wiring between the CT sensor and the control board can interrupt the sensor signal. Inspect connector terminals and wiring harnesses in the outdoor unit for visible damage or poor contact.

  4. 04

    Power surge or electrical overstress

    Part replacement

    A voltage spike or sustained overvoltage condition can damage CT sensor circuitry on the outdoor control board. Check the unit's power supply for proper voltage and inspect for signs of burn marks or component damage on the board.

See the test procedure for each cause

Frequently asked questions about YEL_FLICKER_RED_FLICKER

What does YEL_FLICKER_RED_FLICKER mean on a Samsung air conditioner?
This error code indicates a CT sensor error in the outdoor unit. The CT (current transformer) sensor monitors the electrical current draw of the outdoor system components. When this sensor fails or produces an out-of-range signal, the system halts operation and displays this fault through the yellow and red LED flicker pattern on the outdoor unit.
Can I fix the YEL_FLICKER_RED_FLICKER error myself?
Some basic checks, such as inspecting wiring connections and terminals in the outdoor unit for looseness or corrosion, can be done by a knowledgeable DIYer. However, if those checks do not resolve the issue, the repair requires replacing the outdoor control board, which involves working with high-voltage electrical components. This work is best handled by a qualified HVAC technician.
Is it safe to run my Samsung air conditioner with the YEL_FLICKER_RED_FLICKER error active?
You should not attempt to bypass or ignore this error. The CT sensor monitors current to protect the compressor and outdoor components from electrical faults. Operating the unit without a functioning CT sensor removes an important protective function and could result in compressor damage or further electrical issues.
How much does it cost to repair the YEL_FLICKER_RED_FLICKER error on a Samsung air conditioner?
Repair costs typically depend on whether the fix requires an outdoor control board replacement or just a wiring correction. Board replacement parts alone can range from roughly $150 to $400 or more depending on the specific Samsung model, with labor adding additional cost. Getting a diagnosis from a certified technician will provide a more accurate estimate for your specific unit.
Will resetting my Samsung air conditioner clear the YEL_FLICKER_RED_FLICKER error?
A power reset may temporarily clear the error code, but if the CT sensor or outdoor control board has actually failed, the code will return once the unit attempts to operate. Resetting without addressing the root cause does not resolve the underlying hardware fault and may delay proper repair.

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