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Error code reference

Samsung Refrigerator Error Code DEFROST SENSOR OF R ROOM

Refrigerator Defrost Sensor Error

Samsung codesSamsung refrigerator codes

Refrigerator Defrost Sensor Error - open or short-circuit, connector failure, or temperature reading greater than 122°F or less than -58°F.

First step from the service manual

Check the voltage at MAIN PCB Sensor connector; should be between 4.5V and 1.0V.

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

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What DEFROST SENSOR OF R ROOM means on a Samsung refrigerator

The DEFROST SENSOR OF R ROOM error means the main PCB has detected a fault in the refrigerator compartment defrost sensor circuit. The control board monitors the sensor voltage continuously; when the reading falls outside the 4.5V to 1.0V operating range, or when the sensor reports a temperature above 122°F or below -58°F, the board flags this code. Root causes include an open circuit (broken wire or disconnected connector), a short circuit within the wiring harness, a failed connector at the PCB or sensor end, or a defrost sensor that has drifted out of its calibrated range.

For homeowners, the defrost sensor in the refrigerator compartment tells the control board when to run and stop the defrost cycle. If this sensor fails or loses its connection, the board can no longer accurately control defrosting. Without proper defrost cycles, ice builds up on the evaporator coil, which blocks airflow and causes the refrigerator to lose cooling over time. The error does not mean the fridge is immediately dead, but it will degrade performance if left unaddressed.

The first diagnostic step is to measure the voltage at the MAIN PCB sensor connector pins. A reading between 1.0V and 4.5V means the sensor circuit is functioning; a reading outside this range confirms the fault is real and localized to the sensor, harness, or connector.

Source: manufacturer service documentation.

Common causes of DEFROST SENSOR OF R ROOM

  1. 01

    Failed refrigerator compartment defrost sensor

    Part replacement

    The defrost sensor itself has failed internally, causing it to report temperatures above 122°F or below -58°F, which are outside the valid operating range. This triggers the error because the PCB receives an implausible temperature reading from the sensor.

  2. 02

    Open circuit in sensor wiring harness

    Part replacement

    A broken or severed wire between the defrost sensor and the main PCB interrupts signal continuity, causing the board to read an out-of-range voltage. This type of fault often appears after physical stress on the harness during prior repairs or shipping.

  3. 03

    Disconnected or damaged connector at main PCB or sensor

    Wiring / connection

    A loose, corroded, or physically damaged connector at either the PCB or the sensor terminal can cause an intermittent or permanent open circuit. The board loses the voltage reference it needs and logs the error.

  4. 04

    Short circuit in the sensor wiring harness

    Part replacement

    If the sensor wiring shorts to ground or to another wire, the voltage at the PCB connector drops to zero or reads incorrectly, pulling it outside the 1.0V to 4.5V window. Chafed insulation or pinched wiring near the evaporator cover is a common source of shorts.

See the test procedure for each cause

Frequently asked questions about DEFROST SENSOR OF R ROOM

What does DEFROST SENSOR OF R ROOM mean on a Samsung refrigerator?
This error means the main control board has detected a problem with the defrost sensor in the refrigerator compartment. The sensor is reporting a temperature outside the valid range (above 122°F or below -58°F), or the circuit has an open or short circuit. The board cannot properly control defrost cycles without a valid sensor reading.
How do I fix DEFROST SENSOR OF R ROOM on a Samsung refrigerator?
Start by measuring the voltage at the main PCB sensor connector; it should read between 1.0V and 4.5V. If the voltage is out of range, inspect the wiring harness and connectors between the sensor and the PCB for breaks, corrosion, or loose connections. If the harness checks out, replace the refrigerator compartment defrost sensor. If replacing the sensor does not resolve the code, the main PCB may need to be tested or replaced.
Can I still use my Samsung refrigerator with the DEFROST SENSOR OF R ROOM error active?
The refrigerator will likely continue cooling in the short term, but it is not safe to ignore this error indefinitely. Without a functioning defrost sensor, the control board cannot run defrost cycles correctly, which leads to ice accumulation on the evaporator coil and progressive loss of cooling. Food safety will be at risk once airflow is significantly restricted, so the repair should be completed promptly.
How much does it cost to fix the DEFROST SENSOR OF R ROOM error on a Samsung refrigerator?
If the defrost sensor is the only failed component, the part typically costs between $10 and $40, and replacing it is a DIY-friendly repair requiring basic tools and a multimeter. If the main PCB is also faulty, board replacements range from $100 to $300 for the part alone. A professional technician visit adds $80 to $150 in labor on top of parts.
How do I test the defrost sensor to confirm it is causing the DEFROST SENSOR OF R ROOM error?
Use a multimeter set to DC voltage and probe the sensor connector pins on the main PCB with the refrigerator powered on. A reading between 1.0V and 4.5V indicates the sensor circuit is within normal range. A reading outside this window, or no voltage at all, points to a failed sensor, open wiring, or a shorted harness. You can also test sensor resistance directly after disconnecting it; compare the resistance value against the temperature-resistance chart in the Samsung service manual for your specific model.

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