LG AC error codes – Single / multi-split inverter AC
30 codes from the LG service manual, with what each one means and the usual causes. Shown as CHxx on the display; models without a display blink LEDs (pattern varies by model - see its manual). Checks are standard practice.
You can safely switch the unit off at the switch, wait 5 minutes and switch on again. Don't open the unit, touch wiring or handle gas: these checks need a trained technician.
1also CH01
Indoor room (return air) sensor open/short
What our technician checks
- Room (return air) sensor: unplug and measure - most split ACs use 10 kΩ at 25°C (about 12.6 kΩ at 20°C, 8 kΩ at 30°C). Open or short = faulty. Check connector on the indoor PCB.
2also CH02
Indoor inlet pipe sensor open/short
What our technician checks
- Indoor coil (pipe) sensor: unplug and measure (commonly 10 kΩ or 5 kΩ at 25°C depending on brand). Check it is clipped into the coil sensor pocket.
5also CH05
Indoor-outdoor communication failure
What our technician checks
- Interconnect cable: correct terminal order (L, N, signal, earth), no loose screw or joint, cable not run with other power cables. Is the outdoor unit powered (LED on outdoor PCB)? Signal line voltage fluctuates when healthy. Check outdoor fuse and reactor.
6also CH06
Indoor outlet pipe sensor open/short
What our technician checks
- Indoor coil (pipe) sensor: unplug and measure (commonly 10 kΩ or 5 kΩ at 25°C depending on brand). Check it is clipped into the coil sensor pocket.
9also CH09
Indoor EEPROM error
What our technician checks
- Power off 3 min and restart.
10also CH10
Indoor fan locked (motor failure)
What our technician checks
- Indoor blower turns freely by hand? Blower wheel clean, not rubbing? Fan motor connector, motor supply (AC: capacitor
- DC: about 310 V DC + 15 V and feedback signal).
12also CH12
Indoor middle pipe sensor open/short
What our technician checks
- Indoor coil (pipe) sensor: unplug and measure (commonly 10 kΩ or 5 kΩ at 25°C depending on brand). Check it is clipped into the coil sensor pocket.
21also CH21
DC peak / IPM fault
What our technician checks
- Power off, wait for capacitors to discharge. Compressor U-V, V-W, W-U equal (about 0.5-3 Ω) and >10 MΩ to earth. Diode test the IPM P/N to U/V/W. Check DC bus (about 310 V DC on 230 V supply), heat-sink paste and screws, condenser cleanliness, supply voltage, overcharge.
22also CH22
CT2 - AC input current too high
What our technician checks
- Supply voltage under load, condenser dirty or outdoor fan slow, overcharge, air in system, compressor current against rated.
23also CH23
DC link voltage too low
What our technician checks
- Measure mains under load (single phase normally 200-250 V). Loose neutral, undersized cable, stabiliser.
25also CH25
Supply voltage too low or too high
What our technician checks
- Measure mains under load (single phase normally 200-250 V). Loose neutral, undersized cable, stabiliser.
26also CH26
Inverter compressor locked / not rotating
What our technician checks
- Compressor windings equal and not earthed? U/V/W lead order and connection. Refrigerant pressures equalised before start? Board output to compressor.
27also CH27
PSC / PFC fault (AC-DC converter current high)
What our technician checks
- Power off, wait for capacitors to discharge. Compressor U-V, V-W, W-U equal (about 0.5-3 Ω) and >10 MΩ to earth. Diode test the IPM P/N to U/V/W. Check DC bus (about 310 V DC on 230 V supply), heat-sink paste and screws, condenser cleanliness, supply voltage, overcharge.
28also CH28
Inverter DC voltage too high
What our technician checks
- Measure mains under load (single phase normally 200-250 V). Loose neutral, undersized cable, stabiliser.
29also CH29
Inverter compressor current too high
What our technician checks
- Power off, wait for capacitors to discharge. Compressor U-V, V-W, W-U equal (about 0.5-3 Ω) and >10 MΩ to earth. Diode test the IPM P/N to U/V/W. Check DC bus (about 310 V DC on 230 V supply), heat-sink paste and screws, condenser cleanliness, supply voltage, overcharge.
31also CH31
CT sensor reading too low
What our technician checks
- Current sensing circuit on the outdoor board.
32also CH32
Discharge pipe temperature too high
What our technician checks
- Low refrigerant charge (most common), blocked expansion valve / capillary, EEV not opening, discharge sensor reading wrong.
40also CH40
CT sensor open/short
What our technician checks
- Current sensing circuit on the outdoor board.
41also CH41
Discharge pipe sensor open/short
What our technician checks
- Discharge pipe sensor: measure (typically 50-200 kΩ at 25°C, brand dependent) and check it is fixed on the discharge pipe.
44also CH44
Outdoor air sensor open/short
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
45also CH45
Condenser middle sensor open/short
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
46also CH46
Suction line sensor open/short
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
48also CH48
Condenser outlet (liquid) sensor open/short
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
53also CH53
Outdoor-indoor communication failure
What our technician checks
- Interconnect cable: correct terminal order (L, N, signal, earth), no loose screw or joint, cable not run with other power cables. Is the outdoor unit powered (LED on outdoor PCB)? Signal line voltage fluctuates when healthy. Check outdoor fuse and reactor.
60also CH60
Outdoor PCB EEPROM error
What our technician checks
- Power off 3 min and restart.
61also CH61
Condenser coil temperature too high
What our technician checks
- Condenser dirty or air recirculating, outdoor fan slow, overcharge, air / nitrogen in system, valves closed (heating: indoor filter / fan).
62also CH62
Inverter heat-sink temperature too high
What our technician checks
- Heat-sink fixing and paste, outdoor airflow, high ambient, heat-sink sensor.
63also CH63
Condenser coil temperature too low
What our technician checks
- Suction pressure low? Leak test (flare joints, valves, coils) with soap / nitrogen. Valves fully open?
65also CH65
Heat-sink sensor open/short
What our technician checks
- Outdoor sensor (ambient / coil / suction): unplug and measure against the brand chart (outdoor ones are usually 10 kΩ, discharge sensors 50-200 kΩ at 25°C).
67also CH67
Outdoor BLDC fan motor locked
What our technician checks
- Outdoor fan turns freely (bearing)? Leaves / debris? DC fan: motor supply from the outdoor PCB and feedback wire.
Code not here, or still showing?
Send a photo of the display and the model sticker on WhatsApp. We'll tell you what it means and whether it needs a visit.
Other code lists
- Samsung AC error codes – Inverter split AR09/12/18/24HSF
- Midea AC error codes – Multi-split indoor - 9V, Vertu, 9A, Corona, R, Y, X series
- Midea AC error codes – Multi-split indoor - NEOLA, PREMIER, OASIS series
- Midea AC error codes – Multi-split indoor - A5 Duct series
- Midea AC error codes – Multi-split indoor - Cassette series
- Midea AC error codes – Multi-split indoor - Ceiling & Floor series