LG Air Conditioner Error Codes

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In this complete LG error code guide, we’ll show you the different codes and possible causes affecting LG aircon units — and how you can use them to check and troubleshoot the common issues with your LG air conditioner.

LG Air Conditioner Error Codes: The Complete List

Indoor Unit Faults

Error Code Possible Cause
1 Indoor unit room temperature sensor error
2 Indoor unit inlet pipe sensor error
4 Float switch error (optional)
5 Communication error between indoor unit and outdoor units
6 Indoor unit outlet pipe sensor error
9 Indoor unit EPROM error
10 Indoor unit BLDC motor fan lock
12 Indoor unit middle pipe sensor error

Outdoor Unit Faults

Error Code Possible Cause
21 DC Peak (IPM Fault); Compressor DC voltage was too high
22 Current Transformed (CT2) error; Alternating current (AC) input too high
23 DC Link Low Volt
25 AC Low/High Volt
26 DC Comp Position Error (not providing rotation), Locking
27 PSC Fault; Current to inverter compressor between AC and DC converter circuit too high
28 Inverter compressor DC voltage is too high
29 Inverter compressor amperage is too high
31 Current-to-current transformer (CT) thermistor is too low
32 Inverter Compressor Discharge Pipe (D-Pipe) Overheat
40 CT Sensor Error; Thermistor is disconnected or shorted out
41 D-Pipe Sensor INV is disconnected or shorted out
44 Outdoor Air Sensor is disconnected or shorted out
45 Middle thermistor of outdoor unit condenser coil is disconnected or shorted out
46 Outdoor unit suction line thermistor is disconnected or shorted out
48 Outdoor unit coil outlet (liquid line) thermistor is disconnected or shorted out
53 Communication failure from outdoor unit to indoor unit
60 Outdoor unit printed circuit board (PCB) EPROM check sum error
61 Outdoor unit condenser coil temperature is too high
62 Outdoor unit inverter compressor PCB heat sink temperature is too high
63 Condenser coil pipe thermistor temperature is too low
65 Heat sink thermistor has disconnected or has shorted out
67 Outdoor brushless direct current (BLDC) fan motor lock error

LED Error Codes

Error Code Description LED 01G/M (Red) LED 01G/M (Red) Possible Cause
21 DC Link Peak (IPM Fault) 2 times 3 1 times 3 Over Rated Current
22 CT 2 (Max CT) 2 times 3 Input Over Current
23 DC Link Low Volt.
DC Link High Volt.
3 times 3 DC Link Volt is below 140Vdc
DC Link Volt is above 420Vdc
25 Low Voltage/Over Voltage 5 times 3 Abnormal AC Volt Input
26 DC Compressor Position Error 6 times 3 Compressor Starting Fall Error
27 PSC/PFC Fault Error 7 times 3 Over Inverter PCB input current
29 COMP Over Current 9 times 3 Over Inverter Compressor Current
32 D-Pipe High 3 times 3 2 times 3 D-Pipe Temp. High
35 Low Pressure Error 5 times 3 Excessive decrease of Low Pressure
39 Communication Error 9 times 3 Communication Error Between PFC Micom and INV Micom
40 CT Sensor (Open/Short) 4 times 3 0 CT Circuit Malfunction
41 INV. D-Pipe Th Error 1 times 3 Open/Short
43 High Pressure Sensor Error 3 times 3
44 Outdoor Air Th Error 4 times 3
45 Cond. Mid-Pipe Th Error 5 times 3
46 Suction Pipe Th Error 6 times 3
48 Cond. Out-Pipe Th Error 8 times 3
51 Capacity Over 5 times 3 1 times 3 Over combination
53 Signal Error (Indoor <-> Outdoor) 3 times 3 Communication Poorly
54 3-Phase Wrong wiring 4 times 3 3-Phase Wrong Wring of Outdoor Unit (Reverse Phase/Omission of Phase)
60 EEPROM Check Sum Error 6 times 3 0 Check Sum Mismatching
61 Cond. Pipe Th High 1 times 3 Cond. Temp. High
62 Heat sink Th High 2 times 3 Heatsink Temp. High
65 Heat sink Th Error 5 times 3 Open/Short
67 Outdoor BLDC Fan Lock 7 times 3 Outdoor Fan is not operation
73 PFC Fault Error(SAN) 7 times 3 3 times 3 Over Current of Outdoor Unit PFC

Error Codes with Possible Causes

Error Code Description Possible Cause Check point and normal condition
1 Indoor air sensor • Open / Short
• Soldered poorly
• Internal circuit error
Normal resistor: 10KS2/ at 25°C (Unplugged)
Normal voltage : 2.5Vdc / at 25°C (plugged)
2 Indoor inlet pipe sensor • Open / Short
• Soldered poorly
Normal resistor: 5K£2/ at 25°C (Unplugged)
Normal voltage : 2.5Vdc / at 25°C (plugged)
6 Indoor outlet pipe sensor • Internal circuit error -
3 Communication • Open / Short • Connection of wire
3 Wired R/C • Wrong connection • Main PCB Volt. DC 12V
• Noise interference
4 Drain pump/Float switch • Float switch Open. (Normal: short) • The connection of wire(Drain pump/ Float switch)
• Drain pump power input. (220V)
• Drain tube installation.
• Indoor unit installation. (Inclination)
апр.53 Communication (Indoor - Outdoor) • Communication poorly • Power input AC 220V. (Outdoor, Indoor)
• The connector for transmission is disconnected.
• The connecting wires are misconnected.
• The GND1,2 is not connected at main GND.
• The communication line is shorted at GND.
• Transmission circuit of outdoor PCB is abnormal.
• Transmission circuit of indoor PCB is abnormal.
21 DC Peak • Instant over current
• Over Rated current
• Poor insulation of IPM
• An instant over current in the U,V,W phase
- Comp lock
- The abnormal connection of U,V,W
• Over load condition
- Overcharging of refrigerant
- Pipe length.
• Poor insulation of compressor
22 Max. C/T Over current (14A) Malfunction of compressor
Blocking of pipe
Low voltage input
Refrigerant, pipe length, blocked
40 CfT Internal circuit Initial current error Malfunction of current detection circuit.
(Open / Short)
The voltage of “C01N" Is 4.0Vdc(25A).
23 DC Link • DC link volt, is 140Vdc. • Check the power source.
23 Low voltage. - • Check the components.
28 DC Link High voltage • DC link volt, is 420Vdc T -
24 Press S/W Open • Low / High press • Check the connection of “CN_Press”.
• Check the components.
25 Input voltage • Abnormal Input voltage • Check the power source.
• Check the components.
26 DC Compressor Position • Compressor position detect error • Check the connection of comp wire “U,V,W”
• Malfunction of compressor
• Check the component of “IPM", detection parts.
27 PSC Fault • Over current at "IGBT" • Check the component of “IGBT".
• Check the components.
32 D-pipe (Inverter) temp, high (105°C t) • Discharge sensor (Inverter) temp, high • Check the discharge pipe sensor for INV.
• Check the install condition for over load.
• Check the leakage of refrigerant.
• Check the SVC V/V open.
33 D-pipe (Constant) temp, high (105°C I) • Discharge sensor (Cons.) temp, high • Check the discharge pipe sensor for Cons.
• Check the install condition for over load.
• Check the leakage of refrigerant.
• Check the SVC V/V open.
41 D-pipe sensor (Inverter) • Open / Short
• Soldered poorly
• Internal circuit error
• Normal resistor: 200K£2 / at 25°C (Unplugged)
• Normal voltage : 4.5Vdc / at 25°C (plugged)
44 Air sensor - • Normal resistor: 10K£2 / at 25°C (Unplugged)
• Normal voltage : 2.5Vdc / at 25°C (plugged)
45 Condenser Pipe sensor - • Normal resistor: 5K£2 / at 25°C (Unplugged)
46 Suction Pipe sensor - • Normal voltage : 2.5Vdc / at 25°C (plugged)
47 D-pipe sensor (Constant) - • Normal resistor: 200K£2 / at 25°C (Unplugged)
• Normal voltage : 4.5Vdc / at 25°C (plugged)
65 Heat sink sensor - • Normal resistor: 10K£2 / at 25°C (Unplugged)
• Normal voltage : 2.5Vdc / at 25°C (plugged)
51 Over capacity • Over capacity • Check the indoor unit capacity.
• Check the combination table.
60 EEPROM Check sum • Check sum error • Check the PCB ASM P/No.
• Check the poor soldering.
61 Condenser pipe sensor temp, high • Condenser pipe sensor detected high temp.(65°C) • Check the load condition.
• Check the sensor of Condenser pipe sensor.
62 Heat sink sensor temp, high • Heat sink sensor detected high temp.(85°C) • Check the fan is locked.
• Check the sensor of heat sink.
май.53 Title Communication (Indoor - Outdoor) • Communication poorly • Power input AC 220V. (Outdoor, Indoor)
• The connector for transmission is disconnected.
• The connecting wires are misconnected.
• The communication line is shorted at GND.
• Transmission circuit of outdoor PCB is abnormal.
• Transmission circuit of indoor PCB is abnormal.
21 DC PEAK (IPM Fault) • Instant over current
• Over Rated current
• Poor insulation of IPM
• An instant over current in the U,V,W phase
- Comp lock
- The abnormal connection of U,V,W
• Overload condition
- Overcharging of refrigerant
Pipe length.
Outdoor Fan is stop
• Poor insulation of compressor

Error Code Possible Cause Indicator Operating State
2 Outdoor TH. is short or open. The operating LED will be blinking twice. Keep operating state.
4 Temp. of Heat sink is over 95°C. Heat sink TH. is short or open. The operating LED will be blinking 4 times. Restart compressor when Heat sink
Temp is 85°C below.
5 Communication error (serial communication). The operating LED will be blinking 5 times. The operation is off (enable to restart by remote controller).
6 DC peak error. The operating LED will be blinking 6 times. Compressor will be turned off immediately (not enable to restart by remote controller)
7 Running current is overloaded. The operating LED will be blinking 7 times. Compressor will be turned off immediately (not enable to restart by remote controller)
9 Outdoor fan lock error (BLDC fan model) The operating LED will be blinking 9 times. The operation is off (enable to restart by remote controller).
10 D-PIPE TH is short or open. The operating LED will be blinking 10 times. Compressor will be turned off immediately (restart compressor when D-PIPE TH. is recovered)

Error Code Possible Cause Check/Repair Shop Parts
1 Temperature sensor failure Unplug the air conditioner and check the wire harness connections on the electronic control board. Examine the electronic control board for damage. Check for a pinched or broken wire in the temperature sensor wire harness. Replace the temperature sensor if it’s defective. Temperature sensor, Wire harness, Electronic control board
E2 Failure in the indoor temperature sensor Unplug the air conditioner and check the wire harness connections on the electronic control board. Examine the electronic control board for damage. Check for a pinched or broken wire in the indoor temperature sensor wire harness. Replace the indoor temperature sensor if it’s defective. Indoor temperature sensor, Wire harness, Electronic control board
E3 Abnormal operation protection error Indoor temperature sensor, Wire harness, Electronic control board
E3 Clean or replace filters if dirty. Unplug the window air conditioner and check all components for visible damage. Check fan blades for damage or obstructions and replace any damaged fan blades. Check all wire harness connections. Replace any damaged wire harnesses. Filter, Fan blade, Fan motor, Wire harness
E4 (Portable A/C only) The air conditioner is in the defrost mode After the air conditioner exits defrost mode and resume normal operation, check the unit to see if it’s cooling properly. If so, then the E4 code is normal. If the portable air conditioner frequently goes into the defrost mode and isn’t cooling properly, check the air filters and clean or replace filters if dirty. Filter
P2 or FL (Portable A/C only) The water collection tank is full Empty the water collection tank. If the P2 or FL code appears when the tank is empty, replace the float switch or sensor in the collection tank. Collection tank float switch or sensor

Error Codes with Description

Error Code Function Name Description
01 h Read Coil Status Run/Stop(status), Lock(status), Swing(status), Alarm, Filter Sign(status), Mode Lock(status), Wind Flow Lock(status)
03h Read Holding Registers Operation Mode(status), Fan Speed(status), Room Temperature, Error Code,
Set Room Temperature(status),
Set Lower Temperature(status),
Set Upper Temperature(status),
User Mode(status)
05h Force Single Coil Run/Stop(setting), Lock(setting), Swing(setting), Filter Sign Reset, Mode Lock(setting),
Wind Flow Lock(setting)
06h Preset Single Registers Operation Mode(setting), Fan Speed(setting), Set Room Temperature(setting),
Set Lower Temperature(setting),
Set Upper Temperature(setting),
User Mode(setting)

Other Error Codes

Error Code Possible Cause Solution
Code appears in the display. F1,F2 or F3 Air conditioner is in FAN mode and the number shown is the set fan speed. This is normal. The air conditioner is working properly.
FL The water collection tank is full. Empty the water collection tank.
CH01 Short or open circuit in the indoor air thermistor. Unplug the air conditioner and contact your authorized LG service center.

Also read: Carrier AC Error Codes

We are a well-established air conditioning service and repair company based in Singapore. Our technicians, with years of expertise, are capable of servicing various air conditioner models. Trust us to identify and address any issues with your air conditioner effectively.

If you have other problems with your LG air conditioning unit, then you can check out our article about LG aircon troubleshooting.

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