LG Refrigerator RT Error: Ambient room temperature sensor fault
LG refrigerator error — here’s what you need to know. The rT error code on your LG refrigerator indicates room temperature sensor error — the ambient temperature sensor has failed or is reading outside its valid range. This is a Medium severity issue. What Does rT Mean on an LG Refrigerator? rT (also displayed as […]
~75%
DIY Fixable
From $20 (thermistor) — $300 (control board)
Typical Repair Cost
30 minutes – 2 hours
Pro Repair Time
Quick Assessment
Answer to continue safely
Is it safe to keep using?
Maybe. The refrigerator continues to cool food because the compressor defaults to a safe run schedule. Food safety is not immediately compromised, but higher energy use and possible compressor strain make prompt repair advisable. Monitor internal temperatures to confirm the freezer and fridge remain at proper temperatures.
Can I reset the code?
Yes. Unplugging the unit for 60 seconds clears the rT code from the display. If the thermistor itself is faulty, the code will return once the board re-reads the sensor. A reset is diagnostic confirmation, not a repair.
When to stop immediately?
Stop if you notice: Stop using the refrigerator and call a technician if internal food temperatures begin rising above 40°F (fridge) or 0°F (freezer) — the rT fault may be masking additional cooling faults., Stop running the unit if you notice the compressor motor running continuously for hours at a time without pause — risk of compressor overheating..
Symptoms You May Notice
Compressor runs more frequently or continuously than normal
Without an accurate ambient temperature reading, the control board may default to maximum compressor run time, causing the unit to run louder and consume more energy than usual.
rT code displayed on the control panel
The refrigerator's door display or interior LED panel shows the rT fault code, sometimes accompanied by an audible alert beep.
Door-open alarm does not trigger at expected intervals
Some LG models adjust door alarm timing based on ambient temperature. With the rT fault active, the alarm behaviour may change or become erratic.
Energy usage increases noticeably
Higher-than-normal electricity consumption from the refrigerator, visible on a smart meter or energy monitor, can indicate the compressor is running a fixed aggressive schedule due to the missing ambient reading.
Possible Causes
Failed ambient thermistor (open or short)
The thermistor component has electrically failed — resistance has drifted far out of specification — generating an invalid signal that the board detects as a sensor fault.
DIY PossibleLoose or corroded thermistor connector
The wiring harness connector at the thermistor has worked loose or corroded, creating an intermittent or permanent open-circuit signal on the ambient sensor line.
DIY PossibleDamaged wiring between thermistor and control board
The signal wire running from the ambient thermistor to the main control board can be chafed, pinched by a hinge, or damaged by pests, breaking continuity.
Requires ProfessionalSafe Checks You Can Do
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1
Perform a control board reset
Unplug the refrigerator from the wall outlet for 60 seconds, then restore power. This clears any transient fault memory. Monitor the display — if rT returns within a few minutes, the fault is hardware-based.
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2
Locate and reseat the ambient thermistor connector
The ambient thermistor is typically located near the top hinge on the rear exterior, inside the top-hinge cap, or in the machine compartment. With the refrigerator unplugged, locate the two-wire connector, unplug it, inspect for corrosion or bent pins, and firmly reseat it. Restore power and check if rT clears.
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3
Test thermistor resistance with a multimeter
Disconnect the thermistor connector and measure resistance across the two thermistor wires. At approximately 77°F (25°C) the reading should be 5,000–6,000 Ω for most LG models. A reading near 0 Ω (short) or an overload/open reading confirms a failed thermistor requiring replacement.
When to Call a Professional
Contact a qualified technician if:
- rT returns immediately after reset and reseating the connector — thermistor needs replacement, confirmed by multimeter reading outside 5,000–6,000 Ω at room temperature.
- Wiring harness shows visible damage, corrosion, or chew marks along its run — wiring repair or full harness replacement needed.
- Thermistor resistance is in-spec but rT persists — control board input circuit may have failed, requiring board diagnosis.
Need Professional Help?
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