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Error code reference

Samsung Refrigerator Error Code I/M-SENSOR

Ice Maker Sensor Error (Refrigerator side on Twin I/M units)

Samsung codesSamsung refrigerator codes

Ice Maker Sensor Error (Refrigerator side on Twin I/M units) - open or short-circuit, connector failure, or temperature reading > 122°F or < -58°F.

First step from the service manual

Check voltage at MAIN PCB Sensor between 4.5V~1.0V

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 I/M-SENSOR means on a Samsung refrigerator

The I/M-SENSOR error code indicates the main control board has detected a fault in the ice maker temperature sensor circuit. The board monitors the sensor's voltage output, which should fall between 4.5V and 1.0V under normal operating conditions. When the board reads a voltage outside this range, it flags an open circuit, a short circuit, or a connector failure. Additionally, if the sensor reports a temperature above 122°F or below -58°F, the board treats this as an out-of-range reading and triggers the same error, since those temperatures are physically implausible for the ice maker compartment.

For homeowners, this means the refrigerator's computer has lost reliable communication with the small thermistor that monitors temperature inside the ice maker. The ice maker depends on accurate temperature data to know when to run its freeze and harvest cycles. When the sensor fails or loses its connection, the ice maker may stop producing ice entirely or behave erratically to prevent damage.

The first diagnostic step is checking the voltage at the MAIN PCB sensor connector. A reading between 1.0V and 4.5V confirms the sensor and wiring are functional. A reading at or near 0V suggests a short circuit, while a reading at or near 5V suggests an open circuit or disconnected connector. This voltage check quickly separates a wiring or connector problem from an actual sensor failure.

Source: manufacturer service documentation.

Common causes of I/M-SENSOR

  1. 01

    Disconnected or loose sensor connector at the MAIN PCB

    Wiring / connection

    The connector linking the ice maker sensor to the main PCB can work loose over time due to vibration or thermal cycling. A loose connection causes an open circuit, pushing the voltage reading outside the 1.0V-4.5V window and triggering the error.

  2. 02

    Failed ice maker temperature sensor (thermistor)

    Part replacement

    The thermistor itself can fail internally, either opening the circuit or shorting, which causes the sensor to report an implausible temperature above 122°F or below -58°F. Replacing the ice maker sensor assembly resolves this cause.

  3. 03

    Damaged or shorted wiring harness to the ice maker sensor

    Part replacement

    The wiring harness running from the sensor to the main PCB can develop a short or open circuit from pinching, chafing against refrigerator components, or damage during a prior repair. A shorted harness collapses the voltage toward 0V, while an open harness pulls it toward 5V.

  4. 04

    Faulty main PCB sensor input circuit

    Part replacement

    If the sensor voltage checks within the 1.0V-4.5V range at the PCB connector but the error persists, the main control board's sensor input circuit may have failed internally. This is the least common cause and is only confirmed after ruling out the sensor and wiring.

See the test procedure for each cause

Frequently asked questions about I/M-SENSOR

What does the I/M-SENSOR error code mean on a Samsung refrigerator?
I/M-SENSOR stands for Ice Maker Sensor Error. The main control board detected that the ice maker temperature sensor circuit has an open circuit, a short circuit, or a connector failure, or it received a temperature reading above 122°F or below -58°F, both of which are outside the physically normal range for an ice maker. The board monitors sensor voltage between 1.0V and 4.5V, and any reading outside that window triggers this code.
How do I fix the I/M-SENSOR error on my Samsung refrigerator?
Start by checking the voltage at the ice maker sensor connector on the main PCB. A healthy reading falls between 1.0V and 4.5V. If you read near 0V, suspect a short in the sensor or wiring harness. If you read near 5V, suspect an open circuit, which is often caused by a loose or disconnected connector. Reseat the connector first since this requires no parts. If the voltage stays out of range, test the sensor's resistance and replace the thermistor if it reads open or shorted. Replace the wiring harness if it shows visible damage or continuity failure.
Can I still use my Samsung refrigerator when the I/M-SENSOR error is active?
The refrigerator's cooling and freezing functions will generally continue to operate normally with this error active because the ice maker sensor is separate from the main refrigerator and freezer temperature sensors. However, the ice maker will likely stop producing ice or operate unreliably until the fault is resolved. You can continue using the refrigerator for food storage, but do not rely on the ice maker until the sensor circuit is repaired.
How much does it cost to fix the I/M-SENSOR error code on a Samsung refrigerator?
If the fix is simply reseating a loose connector, there is no parts cost. A replacement ice maker thermistor typically costs between $15 and $40 for the part. A replacement wiring harness runs $20 to $60 depending on the model. If the main PCB is at fault, the board can cost $100 to $300 or more. A service call from a technician to diagnose and repair the issue generally adds $100 to $200 in labor. DIY repair is feasible for connector and sensor replacement if you are comfortable with basic electrical testing using a multimeter.
Will resetting my Samsung refrigerator clear the I/M-SENSOR error?
A power reset by unplugging the refrigerator for a few minutes may temporarily clear the code, but if the underlying sensor circuit fault is still present, the error will return once the board runs its diagnostics again. Clearing the code without fixing the root cause does not resolve the problem. Use the reset only to confirm whether a transient glitch caused the error, and proceed with voltage and continuity testing if the code comes back.

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