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Error code reference

LG Hvac Error Code 41

PCB sees inverter compressor discharge pipe thermistor as open or shorted.

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PCB sees inverter compressor discharge pipe thermistor as open or shorted.

First step from the service manual

Thermistor must be 244,000Ω at 20°C/68°F, 24,400Ω at 90°C/194°F. Ohm thermistor in water; with perfect thermistor & plug connection, change PCB.

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

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What 41 means on a LG hvac

Error code 41 on an LG HVAC system indicates that the PCB (printed circuit board) has detected an abnormal signal from the inverter compressor discharge pipe thermistor. This thermistor is a negative temperature coefficient (NTC) sensor mounted on the discharge line of the inverter compressor. It monitors the temperature of refrigerant gas leaving the compressor, which is a critical data point for protecting the compressor from overheating and for regulating system operation. When the PCB reads a resistance value that falls outside the expected range, it interprets the thermistor as either open (infinite or very high resistance) or shorted (near-zero resistance) and triggers error code 41.

The correct resistance values for this thermistor are approximately 244,000 ohms at 20 degrees C (68 degrees F) and 24,400 ohms at 90 degrees C (194 degrees F). Any reading significantly outside these benchmarks confirms a faulty sensor. Testing should be performed by submerging the thermistor tip in water at a known temperature and measuring resistance with a multimeter. This method isolates the sensor itself from any wiring or connector issues.

If the thermistor resistance tests within specification at both temperature points, the fault likely lies in the wiring harness or connector between the sensor and the PCB. Inspect the connector pins for corrosion, bent terminals, or intermittent contact. If both the thermistor and all connections check out as good, the PCB itself is the suspect component and will need replacement.

Source: manufacturer service documentation.

Common causes of 41

  1. 01

    Failed discharge pipe thermistor

    Part replacement

    The thermistor itself has failed internally, producing a resistance reading that is either open or shorted. Confirm by measuring resistance in water at a known temperature and comparing to the specified values of 244,000 ohms at 20 degrees C and 24,400 ohms at 90 degrees C.

  2. 02

    Loose or corroded thermistor connector

    Wiring / connection

    The connector between the discharge pipe thermistor and the PCB may have a poor or intermittent contact due to corrosion, moisture intrusion, or a bent terminal pin. Visually inspect and reseat the connector to check for this condition.

  3. 03

    Damaged wiring harness

    Part replacement

    The wiring between the thermistor and the PCB may be broken, pinched, or chafed, causing an open or short circuit in the signal line. Check continuity along the full length of the harness with a multimeter.

  4. 04

    Faulty PCB

    Part replacement

    If the thermistor resistance tests correctly at both reference temperatures and all wiring and connectors are in good condition, the PCB may be misreading the thermistor signal due to an internal fault. PCB replacement is the appropriate next step in this scenario.

See the test procedure for each cause

Frequently asked questions about 41

What does 41 mean on a LG hvac?
Error code 41 means the PCB has detected that the inverter compressor discharge pipe thermistor is reading as open or shorted. This thermistor monitors the temperature of refrigerant gas leaving the compressor. The correct resistance values are 244,000 ohms at 20 degrees C and 24,400 ohms at 90 degrees C. The fault can be caused by a bad thermistor, a faulty connector, damaged wiring, or a failed PCB.
Can I fix error code 41 on my LG HVAC myself?
A knowledgeable DIYer can perform the diagnostic steps, including checking the thermistor resistance with a multimeter and inspecting connectors and wiring. However, if the compressor refrigerant circuit or PCB needs to be accessed for replacement, a licensed HVAC technician is typically required. Always disconnect power to the unit before inspecting any electrical components.
Is it safe to run my LG HVAC with error code 41 active?
Running the system with error code 41 active is not recommended. The discharge pipe thermistor protects the inverter compressor from overheating, and without a valid temperature reading, the PCB cannot properly safeguard the compressor. Continued operation under this condition risks compressor damage, which is a significantly more expensive repair.
How much does it cost to repair LG HVAC error code 41?
Repair costs depend on which component has failed. A replacement discharge pipe thermistor is generally a lower-cost part, with repair costs including labor typically ranging from around 100 dollars to 250 dollars. If the PCB requires replacement, total costs can range from 300 dollars to 700 dollars or more depending on the specific unit and labor rates in your area.
Will resetting my LG HVAC clear error code 41?
Power cycling the unit may temporarily clear the error code, but if the underlying fault in the thermistor, wiring, or PCB is still present, the code will return once the system attempts to operate. A reset alone is not a repair. The thermistor and its circuit must be diagnosed and corrected for the error to be permanently resolved.

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