What does LG CH43 mean?
LG CH43 is listed as high pressure sensor fault, master outdoor unit: High-pressure sensor error, and slave 1 outdoor unit: High-pressure sensor error in VRF, Cassette, Ducted rows such as LG Multi V 5 commercial VRF. Official and unofficial listings both cover this code, so the model family decides which one the diagnosis follows. Do not collapse this code across model families; use the model, series, or system type to choose the right row. Confirm the exact model, series, or signal row before accepting a parts quote.
What to do now
Use these steps before customer action, a sensor check, or PCB quote.
Treat it as a fault signal
If CH43 remains displayed or cooling is still abnormal, preserve the code and arrange diagnosis.
No manufacturer reset steps listed for CH43
Capture the complete CH43 display and model stickers first. The manufacturer lists no customer reset procedure; do not treat a generic power-cycle as manufacturer guidance.
Send these to us
CH43 error code, a clear display photo, LG model stickers, affected rooms, operating state when the code appeared, when the fault appears, and exact model so the source can be cross-checked
Choose the listing that matches your unit
The same code has more than one listed meaning. Match the model family, the system type and the unit that shows the code before approving parts.
| Code | What it means | What to check first |
|---|---|---|
| CH43 | High pressure sensor fault. | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
| LG Multi V 5 commercial VRF — master outdoor unit: High-pressure sensor error | master outdoor unit: High-pressure sensor error | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
| LG Multi V 5 commercial VRF — slave 1 outdoor unit: High-pressure sensor error | slave 1 outdoor unit: High-pressure sensor error | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
| LG Multi V 5 commercial VRF — slave 2 outdoor unit: High-pressure sensor error | slave 2 outdoor unit: High-pressure sensor error | Match this meaning to your installed model and the unit that shows the code, then use the checks below. |
- Code
- CH43
- What it means
- High pressure sensor fault.
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
- Code
- LG Multi V 5 commercial VRF — master outdoor unit: High-pressure sensor error
- What it means
- master outdoor unit: High-pressure sensor error
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
- Code
- LG Multi V 5 commercial VRF — slave 1 outdoor unit: High-pressure sensor error
- What it means
- slave 1 outdoor unit: High-pressure sensor error
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
- Code
- LG Multi V 5 commercial VRF — slave 2 outdoor unit: High-pressure sensor error
- What it means
- slave 2 outdoor unit: High-pressure sensor error
- What to check first
- Match this meaning to your installed model and the unit that shows the code, then use the checks below.
Guidance for your model
Notes that match the code to your exact model. Electrical, refrigerant, wiring, resistance and component checks are for a technician.
| Detail | What it says |
|---|---|
| Diagnostic note | High pressure sensor fault. Check DC voltage between white and black cable on plug. Multi V: 1 Vdc = 8 bar up to 2.5 Vdc = 37 bar. |
| Diagnostic note | Record 431 and confirm that the master outdoor unit reported it. Have an authorised LG VRF technician check the named sensor, connector, harness, and service-manual readings before replacing a board. |
| Diagnostic note | Record 432 and confirm that the slave 1 outdoor unit reported it. Have an authorised LG VRF technician check the named sensor, connector, harness, and service-manual readings before replacing a board. |
| Singapore / model note | Unattributed LG fault-code list; confirm against the installed model/service manual before applying. |
| Singapore / model note | LG Singapore lists Multi V 5, but the installed unit nameplate and matching service manual control. Do not apply this row to Multi V i or another LG family. |
- Detail
- Diagnostic note
- What it says
- High pressure sensor fault. Check DC voltage between white and black cable on plug. Multi V: 1 Vdc = 8 bar up to 2.5 Vdc = 37 bar.
- Detail
- Diagnostic note
- What it says
- Record 431 and confirm that the master outdoor unit reported it. Have an authorised LG VRF technician check the named sensor, connector, harness, and service-manual readings before replacing a board.
- Detail
- Diagnostic note
- What it says
- Record 432 and confirm that the slave 1 outdoor unit reported it. Have an authorised LG VRF technician check the named sensor, connector, harness, and service-manual readings before replacing a board.
- Detail
- Singapore / model note
- What it says
- Unattributed LG fault-code list; confirm against the installed model/service manual before applying.
- Detail
- Singapore / model note
- What it says
- LG Singapore lists Multi V 5, but the installed unit nameplate and matching service manual control. Do not apply this row to Multi V i or another LG family.
What to check before repair
Use this split to separate safe evidence capture from the tests a technician should prove before quoting parts.
| You can check | Technician should confirm |
|---|---|
| Before taking any system action on CH43, take a clear display photo. | Confirm which sensor CH43 maps to on the exact model table. |
| Capture the LG indoor and outdoor model stickers so the correct family row is used. | Measure the sensor value against the service-manual resistance or voltage range. |
| The manufacturer lists no customer reset procedure for this code. Note whether one room, several rooms, or the whole system is affected. | Check connector condition, harness continuity, and PCB input before replacing boards. |
- You can check
- Before taking any system action on CH43, take a clear display photo.
- Technician should confirm
- Confirm which sensor CH43 maps to on the exact model table.
- You can check
- Capture the LG indoor and outdoor model stickers so the correct family row is used.
- Technician should confirm
- Measure the sensor value against the service-manual resistance or voltage range.
- You can check
- The manufacturer lists no customer reset procedure for this code. Note whether one room, several rooms, or the whole system is affected.
- Technician should confirm
- Check connector condition, harness continuity, and PCB input before replacing boards.
Sensor or PCB decision
LG CH43 is usually repair-first if a sensor or harness reading is confirmed. Board replacement should wait until the sensor circuit is tested.
Sensor replacement is usually targeted when resistance or voltage readings are out of range.
Harness or connector damage can look like a sensor fault until continuity is checked.
PCB replacement is a later step if the sensor and wiring test correctly.
LG CH43 questions
What does the LG CH43 error mean?
Can I fix a LG CH43 error myself?
Is it safe to keep running the aircon with a CH43 error?
What causes a LG CH43 error?
Will a LG CH43 error need a repair or a full replacement?
What should I send a technician about a LG CH43 error?
Where to go next
Confirm the fault
Share the error code, model number and symptoms so we can assess the likely cause.
Not the right code?
Browse the full LG list or check a few codes in the same fault category.
Read next
Use these if the quote mentions the parts, checks, or repair path this code points to.