Skip to main content
Error code reference
LG Air Conditioner Error Codes
440 error codes documented with diagnostic procedures.
Have your model number? Get codes specific to your unit.
01Indoor room thermistor error (open/short circuit, poor solder, or internal circuit error).02Indoor inlet pipe thermistor error (open/short circuit, poor solder, or internal circuit…03Communication error between wired remote controller and indoor unit04Drain pump malfunction05Communication error between outdoor unit and indoor unit06Indoor outlet pipe thermistor error (open/short circuit, poor solder, or internal circuit…07Operation mode between indoor unit and outdoor unit is different09Indoor unit EEPROM error1Indoor suction temperature thermistor or indoor pipe temperature thermistor is open or…10Poor fan motor operation100System off due to excessive increase of discharge temperature of constant speed…101System off due to excessive increase of discharge temperature of constant speed…102Discharge temperature of Sub2 outdoor unit No.1 constant speed compressor103Discharge temperature of Sub2 outdoor unit No.2 constant speed compressor104Communication error between master outside unit and other outside unit105Transmission error between fan PCB and inverter PCB106Outdoor unit fan PCB IPM failure107Low voltage of main outdoor fan motor driver108Communication error of main outdoor unit fan motor109Excessive rise of high pressure in sub1 outdoor unit11Outdoor unit cannot recognize the indoor unit; addressing signal does not come out for 3…110Reverse connection of R, S, T power line of Sub1 outdoor unit (misconnection or…111Communication error from main outdoor unit to sub1 outdoor unit113Outdoor unit liquid pipe (condenser) temperature sensor error114Outdoor unit sub-cooling inlet/outlet temperature sensor error115Outside unit subcooling outlet temperature sensor error116Outside unit oil level sensor error117Low pressure sensor of sub1 outdoor unit is open or short.118Air temperature sensor of sub1 outdoor unit is open or short.12Misconnection of connecting cables between indoor and outdoor units, or connecting…120Compressor suction pipe temperature sensor of sub1 outdoor unit is open or short.121Discharge temperature sensor of constant speed compressor 1 of sub1 outdoor unit is open…122Discharge temperature sensor of constant speed compressor 2 of sub1 outdoor unit is open…123Temperature sensor of front-side heat exchanger (A) of sub1 outdoor unit is open or short.124Temperature sensor of rear-side heat exchanger (B) of sub1 outdoor unit is open or short.125Liquid pipe (condenser) temperature sensor of sub1 outdoor unit is open or short.126Sub1 outdoor unit excessive cooling inlet temperature sensor open or short.127Sub1 outdoor unit excessive cooling outlet temperature sensor open or short.128Sub2 outdoor unit high pressure sensor open or short (3 units).129Sub2 outdoor unit low pressure sensor open or short (3 units).13PSC error130Sub2 outdoor unit air temperature sensor open or short (3 units).132Compressor suction temperature sensor of sub2 outdoor unit is open or short.133Sub2 outdoor unit constant speed compressor 1 discharge temperature sensor open or short…134Sub2 outdoor unit constant speed compressor 2 discharge temperature sensor open or short…135Temperature sensor of front-side heat exchanger (A) of sub2 outdoor unit is open or short.136Temperature sensor of rear-side heat exchanger (B) of sub2 outdoor unit is open or short.137Outdoor unit liquid pipe (condenser) temperature sensor of sub2 unit is open or short.138Sub2 outdoor unit excessive cooling inlet temperature sensor open or short (3 units).139Sub2 outdoor unit excessive cooling outlet temperature sensor open or short (3 units).14Compressor phase current error (180 driver compressor control model only).140Excessive rise of high pressure in sub2 outdoor unit141Reverse connection of R, S, T power line of Sub2 outdoor unit (misconnection or…142Communication error between outdoor units143Excessive rise in high pressure of sub1 outdoor unit144Excessive drop in low pressure of sub1 outdoor unit145Communication error between Main PCB and External PCB146Low pressure drop of Sub2 outdoor unit147Short voltage or excess voltage of Sub1 outdoor unit148Voltage detection circuit of sub1 outdoor unit is out of order.149Short voltage/excess voltage of Sub2 outdoor unit15Incorrect wiring of compressor phases (U, V, W).150Outdoor unit discharge superheat low151Outdoor 4-way (reversing valve) switching error; pressure change does not occur when Main…152System off due to excessive increase of discharge temperature of constant speed…153System off due to excessive increase of discharge temperature of constant speed…154Excessive rise of high pressure in sub3 outdoor unit155Wrong connection of 3 phase power cable of sub3 outdoor unit (reverse phase or phase…156Transmission error between outdoor units157High pressure sensor of sub3 outdoor unit is open or short.158Low pressure sensor of sub3 outdoor unit is open or short.159Air temperature sensor of sub3 outdoor unit is open or short.161Compressor suction temperature sensor of sub3 outdoor unit is open or short.162Discharge temperature sensor of constant speed compressor 1 of sub3 outdoor unit is open…163Discharge temperature sensor of constant speed compressor 2 of sub3 outdoor unit is open…164Temperature sensor of front-side heat exchanger (A) of sub3 outdoor unit is open or short.165Temperature sensor of rear-side heat exchanger (B) of sub3 outdoor unit is open or short.166Liquid pipe (condenser) temperature sensor of sub3 outdoor unit is open or short.167Subcooling inlet temperature sensor of sub3 outdoor unit is open or short.168Subcooling outlet temperature sensor of sub3 outdoor unit is open or short.169Excessive rise in high pressure of sub3 outdoor unit17FAU inlet air temperature sensor is open or short circuit.170Excessive drop in low pressure of sub3 outdoor unit171Input voltage of sub3 outdoor unit exceeds tolerable range (3phase 380V±10% or single…172Outdoor voltage sensing error of sub3173Failure of main constant speed compressor operation174Failure of Sub1 constant speed compressor 1 operation175Failure of Sub1 constant speed compressor 2 operation176Failure of Sub2 constant speed compressor 1 operation177Failure of Sub2 constant speed compressor 2 operation178Failure of Sub3 constant speed compressor 1 operation179Failure of Sub3 constant speed compressor 2 operation180Plate type heat exchanger freeze prevention error181Water temperature sensor error182Communication error between Main and Sub MICOM of External PCB193Fan PCB heatsink temperature high194Fan PCB heatsink temperature sensor error2Outdoor suction temperature thermistor or outdoor pipe temperature thermistor is open or…200Pipe detection error2001Pipe detection error (HR unit)201HR unit liquid pipe sensor error201C#HRHR unit liquid pipe temperature sensor error202HR unit sub-cooling inlet pipe temperature sensor error202C#HRHR unit sub-cooling inlet pipe temperature sensor error203HR unit sub-cooling discharge pipe temperature sensor error203C#HRHR unit sub-cooling discharge pipe temperature sensor error204Communication error between HR unit and outside unit204C#HRCommunication error between the HR unit and outdoor unit205HR unit 2 liquid pipe temperature sensor error (open or short).205C#HR4 series upgraded 485 communication error between HR unit and HR unit modem.206HR unit 2 sub-cooling inlet pipe temperature sensor error (open or short).206C#HRDuplicate address error of HR unit207HR unit 2 sub-cooling discharge pipe temperature sensor error (open or short).207C#HRCommunication error between Master and Slave Main PCB of HR Unit.208Transmission error between HR unit 2 and outdoor unit.208C#HRCommunication error of EEPROM of HR Unit209HR unit 3 liquid pipe temperature sensor error (open or short).21Master outside unit inverter compressor IPM/IGBT fault210HR unit 3 sub-cooling inlet pipe temperature sensor error (open or short).211HR unit 3 sub-cooling discharge pipe temperature sensor error (open or short).212Transmission error between HR unit 3 and outdoor unit.213HR unit 4 liquid pipe temperature sensor error (open or short).214HR unit 4 sub-cooling inlet pipe temperature sensor error (open or short).215HR unit 4 sub-cooling discharge pipe temperature sensor error (open or short).216Transmission error between HR unit 4 and outdoor unit.217HR unit 5 liquid pipe temperature sensor error (open or short).218HR unit 5 sub-cooling inlet pipe temperature sensor error (open or short).219HR unit 5 sub-cooling discharge pipe temperature sensor error (open or short).22Master outside unit inverter board input over current (RMS)220Transmission error between HR unit 5 and outdoor unit.221HR unit 6 liquid pipe temperature sensor error (open or short).222HR unit 6 sub-cooling inlet pipe temperature sensor error (open or short).223HR unit 6 sub-cooling discharge pipe temperature sensor error (open or short).224Transmission error between HR unit 6 and outdoor unit.225HR unit 7 liquid pipe temperature sensor error (open or short).226HR unit 7 sub-cooling inlet pipe temperature sensor error (open or short).227HR unit 7 sub-cooling discharge pipe temperature sensor error (open or short).228Transmission error between HR unit 7 and outdoor unit.229HR unit 8 liquid pipe temperature sensor error (open or short).23DC voltage charging failure for inverter compressor driving230HR unit 8 sub-cooling inlet pipe temperature sensor error (open or short).231HR unit 8 sub-cooling discharge pipe temperature sensor error (open or short).232Transmission error between HR unit 8 and outdoor unit.24Master outside unit high pressure switch activated240Central controller connector error (CNU connection failure)241Central controller data transmission error (sending error)242Central controller receive error243Central controller receive buffer overflow244Central controller receive timeout245Central controller send timeout246Central controller receive timeout25Input voltage high/low error250Central controller check sum error251Central controller receive zero error252Central controller wrong address error26Outdoor unit inverter compressor start failure27PFC Fault28Master outside unit inverter DC link over-voltage error29Inverter compressor over current3Abnormal operation of multi product; resetting of remote control due to simultaneous…32Master outside unit inverter compressor discharge temperature over-rise33Discharge temperature of constant speed compressor at main outdoor unit is excessively…34Over-increase of discharge pressure of compressor35Low pressure of main outdoor unit; system off by excessive decrease of low pressure by…36Master outside unit low compression ratio limited39Communication error between master outside unit PFC and inverter board, or inverter…4Temperature of heat sink (power module) has exceeded 95°C, causing overheating protection.40Master outside unit inverter compressor CT sensor error41Master outside unit inverter compressor discharge temperature sensor error42Master outside unit low pressure sensor fault43Master outside unit high pressure sensor fault44Outdoor unit air temperature sensor error (sensor measured value not normal, open/short).45Heat exchanger temperature sensor (A) fault in outdoor unit46Outdoor unit compressor suction temperature sensor fault47Constant speed compressor discharge pipe temperature sensor fault48Heat exchanger temperature sensor (B) fault in outdoor unit49Master outside unit IGBT temperature sensor error5Abnormal operation of multi product due to simultaneous cooling and heating operation…50Master outside unit 3-phase power missing51Indoor connection over capacity52Transmission error from inverter PCB to main PCB in outdoor unit53Transmission error from indoor unit to main PCB in outdoor unit54Reverse connection or omitting connection of R, S, T power of main outdoor unit (reverse…55Transmission error from central controller to main PCB in outdoor unit56Transmission error from main PCB in outdoor unit to central controller57Transmission error from main PCB to inverter PCB in outdoor unit59Slave outdoor unit mixed installation6DC peak current error60Outdoor unit EEPROM check sum error61Outdoor pipe temperature (condensation temperature) exceeded 58°C or 60°C in cooling mode62Overheat of inverter PCB heat sink63Condenser pipe low temperature error on outdoor unit.65Outdoor unit liquid pipe (condenser) temperature sensor error67Outdoor unit fan lock7Running current is overloaded (CT270Constant speed compressor CT sensor error71Inverter input current (PFC) CT sensor error73PFC fault error (software)743-phase power unbalance75Fan CT sensor error76Fan DC link high voltage error77Fan over current error78Fan motor hall sensor error79Fan starting failure error8Indoor fan lock error (BLDC fan model only)86Master outside unit Main PCB EEPROM access error87Fan PCB EEPROM error88PFC PCB EEPROM error9Outdoor fan lock error (BLDC fan model only)C1Indoor temperature sensor (thermistor) is short or open circuit.C2Outdoor temperature sensor (thermistor) is short or open circuit.C4Heat sink sensor errorC5Communication error (serial communication) between indoor and outdoor units.C6DC peak current errorC7Over current error (CT2)C8Indoor fan is locked (BLDC fan model only).C9Outdoor fan is locked (BLDC fan model only).CADischarge pipe thermistor (D-Pipe TH) is short or open.CBEEPROM errorCCPSC errorCDCompressor phase current error (180 driver comp control model only).CH00No error present.CH01Indoor air sensor error (connector connection error, faulty PCB, or faulty sensor…CH02Indoor inlet pipe sensor error (connector connection error, faulty PCB, or faulty sensor…CH03Communication error between wired remote controller and indoor unit (connector connection…CH04Drain pump or float switch error (float switch open or water overflow condition).CH05Communication error between indoor and outdoor unitsCH06Open or short circuit of outlet pipe sensor (indoor).CH07Different mode operation errorCH08Indoor fan motor connector open or failureCH09Indoor unit EEPROM error (EEPROM checksum discordance or EEPROM data read error).CH10Indoor unit BLDC motor fan lock (faulty motor operation).CH12Indoor unit middle pipe sensor open/short error.CH15Communication error between indoor PCB and fan board.CH16Fire alarm triggered.CH21DC Peak (IPM Fault)CH22CT 2 (Max CT)CH23DC Link Low VoltageCH24High pressure switch operatedCH25Low voltage or overvoltage condition detected.CH26DC compressor position error (compressor wiring connection error).CH27PSC Fault ErrorCH28DC Link High VoltageCH29Compressor phase over-current.CH31CT error (low current detected).CH32High temperature in discharge pipe of the inverter compressor.CH33Discharge pipe temperature too high (constant speed compressor).CH34High pressure sensor reading is high.CH35Low pressure sensor reading is low.CH36Refrigerant leak / loss detected.CH37Exceed the compression ratio limit.CH38Refrigerant leakage detection (alternate code for CH36).CH40CT sensor open or short circuitCH41Inverter discharge pipe thermistor open or short circuit.CH42Low pressure sensor open or short circuit.CH43High pressure sensor open or short circuit.CH44Outdoor air temperature thermistor open or short circuit.CH45Condenser pipe temperature sensor error (open/short)CH46Suction pipe temperature sensor error (open/short)CH47Constant-speed discharge pipe thermistor open or short circuit.CH48Condenser pipe temperature sensor error (open/short)CH49Voltage sensor open or short circuit.CH51Excess capacityCH52Communication error between inverter board and main board.CH53Communication error between outdoor unit and indoor unit.CH54Phase error on outdoor unitCH55Communication error (outdoor unit receiving from central controller).CH56Communication error (outdoor unit sending to central controller).CH60EEPROM checksum errorCH61Condenser pipe temperature too high.CH62High temperature in outdoor PCBA heat sink.CH63Condenser pipe temperature too low.CH64Momentary power interruption detected.CH65Heatsink thermistor open or short circuit.CH67Outdoor BLDC motor fan lock (faulty motor operation).CH72Detect 4-way valve transfer failure.CH93Communication error between indoor and outdoor units (alternate code).CLChild lock is active; all keys on wired remote are locked.E1Indoor pipe thermostat short or open circuit.E101Indoor unit communication errorE102Communication error between indoor unit and outdoor unit, displayed in indoor unit.E108Error due to repeated address setting when 2 or more devices have the same address within…E121Error on indoor temperature sensor of indoor unit (Short or Open).E122Error of EVA-IN or EVA-OUT sensor in the indoor unit (Open/Short).E123Error of Eva In sensor in the indoor unit (Open/Short).E128EVA IN temperature sensor of indoor unit is detached from EVA IN pipe.E129EVA OUT temperature sensor of indoor unit is detached from EVA OUT pipe.E130Heat exchanger in/out sensors of indoor unit are detached.E135RPM feedback error of indoor unit's cleaning fan.E149Error due to AHU master indoor unit sensor setting.E151Error due to opened EEV of indoor unit (2nd detection).E152Error due to closed EEV of indoor unit (2nd detection).E153Error on floating switch of indoor unit (2nd detection).E154Error of Fan motor in the indoor unit.E161Mixed operation mode error of indoor unit; outdoor unit preparing cooling/heating while…E162EEPROM error of MICOM (physical problem of parts/circuit).E163Indoor unit's remote controller option input is incorrect or missing; outdoor unit EEPROM…E180Simultaneous opening of cooling/heating MCU SOL V/V (1st detection).E181Simultaneous opening of cooling/heating MCU SOL V/V (2nd detection).E185Cross wiring error between communication and power cable of indoor unit.E186Connection error or problem on SPi.E190No temperature changes in EVA IN during pipe inspection or changes in temperature seen in…E191No temperature changes in EVA OUT during pipe inspection or changes in temperature seen…E198Error due to disconnected thermal fuse of indoor unit.E2Indoor air thermostat short or open circuit.E201Communication error between indoor and outdoor units (installation number setting error…E202Communication error between indoor and outdoor units (communication error on all indoor…E2031 minute time out of communication error between Main PCB and Inverter PCB.E205Communication error on all PBA within the outdoor unit C-Box, communication cable error.E206Internal PCB communication error of the outdoor unit C-Box (C001E211MCU branch part setup errorE212MCU rotary switch for address setting has 3 or more of the same address.E213Indoor unit assigned on MCU is not actually installed even though total count matches.E214MCU quantity not set correctly on outdoor unit or duplicate MCU addresses exist.E215Two different MCUs have same address value on rotary switch.E216Indoor unit not installed to MCU port but port switch is set to On.E217Indoor unit connected to MCU port but port switch is set to Off.E218More indoor units actually connected than assigned to MCU.E219Error on temperature sensor located on MCU intercooler inlet (Short or Open).E220Error on temperature sensor located on MCU intercooler outlet (Short or Open).E221Error on outdoor temperature sensor of outdoor unit (Short or Open).E224Error on water temperature sensor of main outdoor unit (Short or Open).E225Error on control box temperature sensor of main outdoor unit (Short or Open).E231Error on COND OUT temperature sensor of main outdoor unit (Short or Open).E241COND OUT sensor is detached from pipe.E251Error on discharge temperature sensor of compressor 1 (Short or Open).E257Error on discharge temperature sensor of compressor 2 (Short or Open).E262Discharge temperature sensor of compressor 1 is detached from the sensor holder on the…E263Discharge temperature sensor of compressor 2 is detached from the sensor holder on the…E266Top sensor of compressor 1 is detached.E267Top sensor of compressor 2 is detached.E269Suction temperature sensor is detached from the sensor holder on the pipe.E276Error on top sensor of compressor 1 (Short or Open).E277Error on top sensor of compressor 2 (Short or Open).E291Refrigerant leakage or error on high pressure sensor (Short or Open).E296Refrigerant leakage or error on low pressure sensor (Short or Open).E3Pipe temperature and room temperature are too close together.E308Error on suction temperature sensor (Short or Open).E311Error on temperature sensor of double layer pipe/liquid pipe (sub heat exchanger) (Short…E320OLP sensor error (open/short).E321Error on EVI (ESC) IN temperature sensor (Short or Open).E322Error on EVI (ESC) OUT temperature sensor (Short or Open).E323Error on suction sensor 2 (Short or Open).E346Error due to operation failure of Fan2.E347Motor wire of Fan2 is not connected.E348Lock error on Fan2 of outdoor unit.E353Error due to overheated motor of outdoor unit's Fan2.E355Error due to overheated IPM of Fan2 (IPM internal temperature more than 85°C).E361Error due to operation failure of inverter compressor 2.E364Error due to over-current of inverter compressor 2.E365V-limit error of inverter compressor 2.E366Error due to over voltage/low voltage of inverter PBA2.E367Error due to unconnected wire of compressor 2.E368Output current sensor error of inverter PBA2.E369DC voltage sensor error of inverter PBA2.E371Error due to INV2 Data Flash.E374Heat sink temperature sensor error of inverter PBA2.E378Error due to overcurrent of Fan2.E383Error due to over current of Fan2.E385Error due to input current of inverter 2.E386Over-voltage/low-voltage error of Fan2.E387Hall IC connection error of Fan2.E389V-limit error on Fan2 of compressor.E391Error due to Fan2 DataFlash.E393Output current sensor error of Fan2.E396DC voltage sensor error of Fan2.E399Heat sink temperature sensor error of Fan2 PBA IPM.E4Product running above 10 minutes and pipe temperature below 2 degrees.E400Error due to overheat caused by contact failure on IPM of Inverter PBA2 (IGBT module…E403Detection of outdoor freezing when compressor is stopped.E404Protection of outdoor overload when compressor is stopped.E407Compressor operation stop due to high pressure protection control (high pressure sensor…E410Compressor operation stop due to low pressure protection control or refrigerant leakage.E416Compressor operation stop due to discharge temperature/top temperature sensor protection…E422EEV or Valve Close errorE425Phase reversal or phase failure on 3-phase outdoor unit wiring (R-S-T-N), connection…E428Compressor operation stop due to abnormal compression ratio.E435Flow Switch Error.E436Error on the heat exchanger frost protection.E438EVI (ESC) EEV leakage or internal leakage of intercooler or incorrect connector insertion…E439Error due to refrigerant leakage.E440Heating operation is not available since the outdoor air temperature is over 30°C.E441Cooling operation is not available since the outdoor air temperature is lower than -5°C.E442Refrigerant charging restriction in heating mode when air temperature is over 15°C.E443DVM Water heating mode restriction due to low water temperature.E445Refrigerant charging restriction in heating mode when air temperature is over 15°C / CCH…E446Error due to operation failure of Fan1.E447Motor wire of Fan1 is not connected.E448Lock error on Fan1.E452Error due to ZPC detection circuit problem or power failure (momentary blackout).E453Error due to overheated motor of outdoor unit's Fan1.E454Error due to outdoor unit fan RPM.E455Error due to overheated IPM of Fan1 (IPM internal temperature more than 85°C).E457Outdoor unit reversed direction of the wind error.E458Outdoor unit BLDC Fan 1 error.E461Error due to operation failure of inverter compressor 1.E462Compressor stop due to full current control or error due to low current on CT2.E463Over current trip / PFC over current error.E464Error due to over-current of inverter compressor 1.E465V-limit error of inverter compressor 1.E466Error due to over voltage/low voltage of inverter PBA1.E467Error due to unconnected wire of compressor 1.E468Output current sensor error of inverter PBA1.E469DC voltage sensor error of inverter PBA1.E470Outdoor EEPROM error (checksum).E471Outdoor EEPROM read/write error.E474Heat sink temperature sensor error of inverter PBA1.E475Outdoor unit BLDC Fan 2 error.E478Error due to overcurrent of Fan1.E483Error due to over current of Fan1.E484PFC Overload Error.E485Error due to input current of inverter 1.E486Error due to over voltage/low voltage of Fan PBA.E487Hall IC error of Fan1.E489V-limit error on Fan1 of compressor.E491Error due to Fan1 DataFlash.E493Output current sensor error of Fan1.E496DC voltage sensor error of Fan1.E499Heat sink temperature sensor error of Fan1 PBA IPM.E500Error due to overheat caused by contact failure on IPM of Inverter PBA1 (IGBT module…E503Error due to alert the user to check if the service valve is closed.E504Error due to self diagnosis of compressor operation.E505Error due to self diagnosis of high pressure sensor.E506Error due to self diagnosis of low pressure sensor.E508Error due to not using Smart Install.E515Error due to overheat of control box.E516Error due to no feedback from the fan of the control box.E552Compressor down due to low discharge pressure.E554Gas leak error (outdoor unit refrigerant full leakage).E556Capacity mismatch between indoor and outdoor units.E557Option code mismatch among the indoor units (only for DPM).E560Outdoor unit's option switch setting error (when inappropriate option switch is on).E563Error due to module installation of indoor unit with old version (Micom version needs to…E573Error due to using single type outdoor unit in a module installation.E590Outdoor EEPROM checksum error between MAIN and INVERTER.E702Error due to closed EEV of indoor unit (1st detection).E703Error due to opened EEV of indoor unit (1st detection).FLWater full indicator display code.P2Water full condition detected for 10 seconds.UPAuto Trial Operation not completed (UnPrepared)
Get the full diagnostic procedure for any code
Step-by-step tests, expected values, wiring diagram references, and verified part numbers.
Get Started $9.95 3-day pass$29/month for all brands and Max diagnostics, with 70 Max messages a day. Plus applicable tax.