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Error code reference

Samsung Air Conditioner Error Code OUTDOOR_GREEN_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 OUTDOOR_GREEN_RED_FLICKER means on a Samsung air conditioner

The OUTDOOR_GREEN_RED_FLICKER error code on a Samsung air conditioner indicates a CT (current transformer) sensor error in the outdoor unit. The CT sensor is responsible for measuring the electrical current flowing through the compressor and other outdoor unit components. This real-time current data is used by the outdoor control board to monitor operating conditions, protect the compressor from overcurrent situations, and ensure the system runs within safe electrical parameters. When the control board cannot read a valid signal from the CT sensor, it triggers this fault and halts normal operation.

This error is communicated visually through the outdoor unit's LED indicator lights, specifically a flickering pattern alternating between the green and red LEDs. The CT sensor is typically integrated into the wiring harness connected to the outdoor control board, measuring current on the compressor power leads. A failure can occur due to a broken or shorted sensor, damaged wiring between the sensor and the board, or a faulty control board that misinterprets the signal entirely.

Because the CT sensor input is processed directly by the outdoor control board, a board failure can produce the same error symptoms as a failed sensor. The recommended first diagnostic step is replacement of the outdoor control board, which suggests that board-level faults are a primary cause of this error. Technicians should also inspect the CT sensor wiring harness for continuity, visible damage, or loose connector pins before condemning any component.

Source: manufacturer service documentation.

Common causes of OUTDOOR_GREEN_RED_FLICKER

  1. 01

    Faulty outdoor control board

    Part replacement

    The outdoor control board processes the CT sensor signal, and an internal board failure can cause it to report a sensor error even if the sensor itself is functional. Replacing the board is the recommended first diagnostic step.

  2. 02

    Failed CT sensor

    Part replacement

    The CT sensor itself may have failed due to overheating, age, or electrical surge. A failed sensor will produce no signal or an out-of-range signal to the control board, triggering the error.

  3. 03

    Damaged or disconnected wiring harness

    Wiring / connection

    The wiring between the CT sensor and the outdoor control board may be broken, chafed, or have a loose connector. Inspect the harness visually and check continuity to identify this issue.

  4. 04

    Corroded or loose connector pins

    Wiring / connection

    Moisture intrusion in the outdoor unit can cause connector pins at the CT sensor or control board to corrode, increasing resistance and disrupting the signal. Clean or replace affected connectors if corrosion is found.

See the test procedure for each cause

Frequently asked questions about OUTDOOR_GREEN_RED_FLICKER

What does OUTDOOR_GREEN_RED_FLICKER mean on a Samsung air conditioner?
This error code indicates a CT sensor error in the outdoor unit. The CT sensor monitors electrical current through the outdoor unit components, and when the control board cannot receive a valid signal from it, the outdoor unit's green and red LEDs will flicker and the system will stop operating normally. The fault can originate from the CT sensor itself, its wiring, or the outdoor control board.
How do I fix the OUTDOOR_GREEN_RED_FLICKER error on my Samsung air conditioner?
The first recommended step is to replace the outdoor control board, as a board failure is a primary cause of this error. If replacing the board does not resolve the fault, the CT sensor and its wiring harness should be inspected for damage, loose connections, or corrosion. This repair involves working inside the outdoor unit with high-voltage components and should be performed by a qualified technician.
Is it safe to run my Samsung air conditioner when the OUTDOOR_GREEN_RED_FLICKER error is active?
No, you should not attempt to run the unit while this error is active. The CT sensor protects the compressor from overcurrent conditions, and operating without a valid sensor reading removes that protection. Continued operation could result in compressor damage or an electrical safety hazard.
How much does it cost to repair the OUTDOOR_GREEN_RED_FLICKER error on a Samsung air conditioner?
Repair costs vary depending on which component has failed. An outdoor control board replacement typically runs in the range of $200 to $500 including parts and labor. CT sensor replacement is generally less expensive, often in the $100 to $300 range. Diagnostic fees from an HVAC technician will also apply and vary by region.
Will resetting my Samsung air conditioner clear the OUTDOOR_GREEN_RED_FLICKER error?
A power reset may temporarily clear the error code, but it will return if the underlying hardware fault is still present. The CT sensor error is triggered by a real electrical signal problem, not a software glitch, so resetting the unit does not address the root cause. A proper component inspection and repair is required to permanently resolve the fault.

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