LG Ice Maker IS Error: Ice maker temperature sensor fault
LG ice maker error — here’s what you need to know. The IS error code on your LG ice maker indicates an ice maker temperature sensor fault. This is a Medium severity issue. What Does IS Mean on an LG Ice Maker? The IS code means the ice maker’s built-in temperature sensor (thermistor) has failed […]
~55%
DIY Fixable
From 5
Typical Repair Cost
30 min–1.5 hours
Pro Repair Time
Quick Assessment
Answer to continue safely
Is it safe to keep using?
Maybe. The refrigerator/freezer section will continue to operate normally. However, the ice maker should be turned off until the IS fault is resolved to avoid producing underformed ice that could jam the harvest mechanism
Can I reset the code?
Yes. Pressing the ice maker test/reset button or power-cycling the refrigerator can clear the IS code. If the thermistor is defective the code will return once the board completes its next freeze-cycle check
When to stop immediately?
Stop if you notice: Ice is jamming in the harvest mechanism and the motor is straining, IS code returns within one full ice-making cycle after reset.
Symptoms You May Notice
Ice maker stops producing ice
The ice maker halts production entirely because it cannot confirm via the sensor that cubes have frozen to the correct temperature before attempting a harvest
Ice cubes are undersized or hollow
With incorrect temperature feedback, the harvest cycle triggers too early, releasing cubes that have not fully frozen and resulting in small or hollow pieces
IS code on the ice maker or refrigerator display
The IS fault code appears on the appliance display, sometimes alongside a pause in the ice maker's operation cycle
Inconsistent temperature performance
The ice maker runs too hot, too cold, or cycles erratically because the control board receives inaccurate temperature readings from the faulty sensor.
Possible Causes
Failed ice maker thermistor
The thermistor has aged out of its rated resistance curve from the constant thermal cycling between -4°F and 32°F during normal ice production
Requires ProfessionalLoose or corroded sensor connector
The small wiring connector linking the sensor to the ice maker harness has come loose or developed corrosion from moisture, breaking the signal
DIY PossibleIce bridging around the sensor mount
Ice has formed a bridge connecting cubes in the tray to the sensor mounting bracket, creating a thermal mass that skews the temperature reading
DIY PossibleSafe Checks You Can Do
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1
Reset the ice maker
Locate the test/reset button on the ice maker module (usually a small rectangular button on the underside of the unit) and hold it for 3 seconds. This initiates a test cycle and resets the sensor reading
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2
Check for ice bridging around the sensor
Turn off the ice maker and allow any ice bridge in the tray to melt for 30 minutes. Restart the ice maker and see if a normal harvest cycle clears the IS code
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3
Inspect and reseat the sensor connector
Turn off the ice maker and locate the wiring connector at the back of the ice maker module where it meets the freezer wall harness. Disconnect and firmly reconnect the plug, checking for moisture or bent pins
When to Call a Professional
Contact a qualified technician if:
- Sensor thermistor resistance tests outside the manufacturer's specification — replacement required
- Code persists after replacing the thermistor — ice maker assembly or main board at fault
- Connector corrosion has spread to the wiring harness inside the freezer wall
Need Professional Help?
Find qualified technicians in your area for proper diagnostics and repair.
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