mypros+
Error code reference

GE Refrigerator Error Code I/M-SENSOR

Ice Maker Sensor Error

GE codesGE refrigerator codes

Ice Maker Sensor Error - 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.

MyPros+ Max

Get the full diagnostic procedure for I/M-SENSOR.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What I/M-SENSOR means on a GE refrigerator

The I/M-SENSOR error code on a GE refrigerator indicates a fault detected in the ice maker temperature sensor circuit. This sensor is a thermistor that monitors the temperature within the ice maker assembly and reports readings back to the main PCB. The control board expects the sensor signal voltage to fall between 4.5V and 1.0V during normal operation. When the voltage falls outside this window, or when the sensor detects temperatures above 122°F or below -58°F, the board flags the fault and displays this code.

The root cause is typically one of three conditions: an open circuit in the sensor wiring (broken wire or disconnected connector), a short circuit that drives voltage out of the acceptable range, or a failed thermistor element itself producing out-of-range resistance and therefore an out-of-range voltage signal. Connector corrosion or physical damage to the wiring harness at the ice maker are common contributors, especially in units where the ice maker has been removed for service or where moisture intrusion has occurred over time.

Diagnosis should begin at the main PCB sensor connector, checking for the 4.5V to 1.0V signal voltage with the refrigerator powered on. If voltage is absent or out of range, the next step is to inspect the wiring harness for continuity and check the connector for corrosion or bent pins. A thermistor that reads open or shorted will need replacement, and connector failures can sometimes be resolved with cleaning or re-termination of the harness.

Source: manufacturer service documentation.

Common causes of I/M-SENSOR

  1. 01

    Faulty Ice Maker Thermistor

    Part replacement

    The thermistor element itself can fail open or short internally, pushing the signal voltage outside the 4.5V to 1.0V range the main PCB expects. A resistance check of the thermistor will reveal an open circuit, a dead short, or a value inconsistent with the actual ice maker temperature.

  2. 02

    Disconnected or Corroded Connector

    Wiring / connection

    The sensor connector at the ice maker or main PCB can loosen, corrode, or develop bent pins over time, interrupting the signal circuit entirely. Visually inspect both ends of the connector for green corrosion, pushed-back terminals, or incomplete seating.

  3. 03

    Damaged Wiring Harness

    Part replacement

    A broken or pinched wire anywhere along the sensor harness between the ice maker and the main PCB will create an open circuit. Check the harness routing for areas where wires may be chafed against cabinet edges or caught in a hinge point.

  4. 04

    Extreme Actual Temperature Condition

    Wiring / connection

    If the ice maker compartment has genuinely reached above 122°F due to a defrost system failure or airflow blockage, the sensor may be reporting accurately and the root cause is not the sensor itself. Check the defrost system and verify that condenser airflow is unobstructed before replacing the thermistor.

  5. 05

    Main PCB Sensor Input Failure

    Part replacement

    If sensor voltage and wiring continuity both check out correctly but the error persists, the sensor input circuit on the main PCB may be damaged. This is the least common cause and should only be considered after all wiring and sensor components have been confirmed good.

See the test procedure for each cause

Frequently asked questions about I/M-SENSOR

What does I/M-SENSOR mean on a GE refrigerator?
The I/M-SENSOR code indicates a fault in the ice maker temperature sensor circuit. The main PCB monitors a signal voltage from the ice maker thermistor that should stay between 4.5V and 1.0V. The error triggers when the voltage falls outside that range, when the circuit is open or shorted, or when the sensor reports a temperature above 122°F or below -58°F.
How do I fix the I/M-SENSOR error on my GE refrigerator?
Start by checking the voltage at the main PCB sensor connector with the unit powered on, looking for a reading between 4.5V and 1.0V. If voltage is absent or incorrect, inspect the wiring harness and sensor connector for damage or corrosion. A thermistor that tests open or shorted will need to be replaced. If wiring and the sensor check out, the main PCB sensor input circuit may need evaluation.
Is it safe to keep using my refrigerator when the I/M-SENSOR code is showing?
The refrigerator's main cooling compartment will typically continue operating, so food safety is not an immediate concern. However, the ice maker will likely stop producing ice or operate unreliably while this fault is active. It is best to address the error promptly to prevent any secondary issues from developing.
How much does it cost to repair an I/M-SENSOR error on a GE refrigerator?
If the fix is limited to cleaning or reseating a connector, there may be no parts cost at all. Replacing the ice maker thermistor typically involves parts costs in the range of $15 to $60 depending on the model. If a technician is needed for diagnosis and repair, total service costs including labor generally range from $100 to $300, with main PCB replacement representing the higher end of that spectrum.
Will resetting my GE refrigerator clear the I/M-SENSOR error code?
A reset may temporarily clear the code from the display, but it will return quickly if the underlying sensor circuit fault has not been corrected. A power cycle or control board reset does not repair a failed thermistor, broken wire, or damaged connector. The error should be treated as an active fault that requires physical diagnosis rather than a software glitch that a reset will resolve.

Related GE refrigerator codes

All GE refrigerator codes
View all 540 GE refrigerator codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass