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Error code reference

Samsung Air Conditioner Error Code qx

Error of temperature sensor in the indoor unit OPEN/SHORT (x = indoor unit address 0-F).

Samsung codesSamsung air conditioner codes

Error of temperature sensor in the indoor unit OPEN/SHORT (x = indoor unit address 0-F).

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What qx means on a Samsung air conditioner

The Samsung air conditioner error code Qx (where x represents the indoor unit address, ranging from 0 to F in hexadecimal notation) indicates a fault with the temperature sensor located inside the indoor unit. This sensor is a thermistor, a resistive component whose electrical resistance changes predictably with temperature. The control board continuously monitors the sensor's resistance to determine the current room or coil temperature. When the resistance reading falls outside the expected range, either due to an open circuit (infinite or very high resistance) or a short circuit (near-zero resistance), the system generates the Qx fault and halts normal operation to prevent potential damage.

The two failure modes, open and short, point to different underlying issues. An open circuit condition typically means the thermistor wire has broken, the connector has pulled apart, or the thermistor element itself has failed internally. A short circuit condition usually indicates the thermistor leads are touching each other, a wire has chafed through its insulation and is contacting a ground, or the thermistor has degraded and its resistance has collapsed. Both conditions cause the control board to receive invalid temperature data, making accurate system control impossible.

In multi-zone or VRF systems, the x digit in the code identifies exactly which indoor unit is reporting the fault, which is critical for diagnostics in installations with multiple air handlers. Technicians should focus attention on the specific unit address displayed. Sensor failures can occur gradually due to vibration, moisture ingress, or thermal cycling over time, or suddenly due to physical damage during servicing or pest intrusion.

Source: manufacturer service documentation.

Common causes of qx

  1. 01

    Failed thermistor

    Part replacement

    The thermistor element itself has degraded internally, causing its resistance to read either open (too high) or shorted (too low). Testing the thermistor with a multimeter will show a reading far outside the expected resistance range for the current ambient temperature.

  2. 02

    Loose or disconnected sensor connector

    Wiring / connection

    Vibration or accidental disturbance during servicing can cause the thermistor harness connector to partially or fully separate from the control board or sensor body. Inspect the connector at both ends for secure seating and signs of corrosion.

  3. 03

    Damaged sensor wiring

    Part replacement

    The wiring between the thermistor and the control board may have chafed, been pinched, or broken, creating an open or short circuit in the signal path. Visually trace the wire along its full routing and check continuity with a multimeter.

  4. 04

    Moisture or corrosion at sensor or connector

    Wiring / connection

    Condensation or water ingress can corrode the thermistor leads or connector pins, increasing resistance or causing intermittent shorts. Look for visible oxidation or discoloration at connection points.

  5. 05

    Faulty indoor unit control board

    Part replacement

    If the thermistor and all wiring test within normal specifications, the control board's sensor input circuit may have failed and is misreading a good sensor as open or shorted. This is the least common cause and should be diagnosed only after all other components are confirmed good.

See the test procedure for each cause

Frequently asked questions about qx

What does qx mean on a Samsung air_conditioner?
The Qx error code on a Samsung air conditioner indicates an open or short circuit fault with the temperature sensor (thermistor) in the indoor unit. The letter x in the code is a hexadecimal digit from 0 to F that identifies the specific indoor unit address reporting the problem. The system cannot read a valid temperature and has stopped normal operation as a result. The sensor, its wiring, and its connector are the primary areas to inspect.
Can I fix the Qx error on my Samsung air conditioner myself?
A knowledgeable DIYer can start by checking whether the sensor connector is fully seated and the wiring is undamaged, as these are the simplest fixes and require no parts. Testing the thermistor with a multimeter requires basic electronics knowledge but is achievable without special tools. Replacing the thermistor itself is a straightforward repair if the correct part is sourced. However, if the control board is suspected, professional diagnosis is recommended to avoid unnecessary parts replacement.
Is it safe to run my Samsung air conditioner with a Qx error active?
Running the unit with an active Qx error is not recommended. The system relies on the indoor temperature sensor to regulate operation, and without valid sensor data it cannot control cooling or heating accurately. Continued operation could result in the unit running outside safe parameters, potentially causing compressor stress or inadequate climate control. It is best to resolve the fault before returning the unit to regular service.
How much does it cost to repair a Qx error on a Samsung air conditioner?
If the fix is simply reseating a loose connector, the repair may cost nothing beyond a service call fee, which typically ranges from $50 to $150. Replacing a thermistor is a low-cost repair with parts generally ranging from $10 to $40, plus labor. If the control board needs replacement, costs are significantly higher, typically ranging from $200 to $600 or more depending on the unit model and labor rates in your area.
Will resetting my Samsung air conditioner clear the Qx error code?
A power reset may temporarily clear the Qx error if the fault was caused by a transient condition such as a momentarily loose connector. However, if the thermistor, wiring, or control board has a genuine defect, the code will return once the system restarts and re-checks the sensor. A reset should not be treated as a permanent fix. The underlying cause must be diagnosed and corrected to prevent the fault from recurring.

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