LG mini split indoor thermistor
Part: 6615A20042A
For CH01 room-sensor faults. Match the connector, resistance curve, and full indoor-unit model.
$10-$60
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LG Mini Split Error Codes — Quick Reference
LG mini-splits use “CH” (Check) codes displayed on the indoor unit’s LED display or the wireless remote controller. On most LG systems, hold the SLEEP button for 3 seconds to display the current error code. LG Art Cool, Dual Inverter Compressor, and LGRED heat pump systems all use the same CH code format.
| Code | Meaning | Quick Fix |
|---|---|---|
| CH01 | Indoor intake thermistor fault | Replace indoor air thermistor |
| CH02 | Indoor pipe thermistor fault | Replace indoor pipe thermistor |
| CH05 | Communication error | Check signal wiring between units |
| CH07 | Indoor PCB fault | Replace indoor PCB |
| CH10 | Outdoor pipe thermistor fault | Replace outdoor pipe thermistor |
| CH12 | Outdoor discharge pipe thermistor | Replace discharge thermistor |
| CH21 | Outdoor PCB fault | Inspect outdoor board and fuses |
| CH22 | Outdoor EEPROM fault | Replace outdoor PCB |
| CH23 | DC fan motor fault | Check outdoor fan motor |
| CH25 | IPM (inverter power module) fault | Check outdoor board; IPM failure |
| CH32 | Overcurrent protection | Check refrigerant; compressor load |
| CH33 | High pressure protection | Clean outdoor coil; check charge |
| CH34 | Low pressure protection | Check refrigerant charge |
| CH35 | Discharge temperature protection | Low refrigerant or expansion valve |
| CH38 | Outdoor fan speed not detected | Fan motor fault |
| CH44 | Drain float switch activation | Clear drain line; check pump |
| CH67 | Inverter compressor fault | Compressor or IPM failure |
| CH68 | PFC protection | Input power quality issue |
Need Replacement Parts?
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Most Common Codes
CH01: Indoor Intake Thermistor Fault
The room temperature sensor on the indoor unit has failed or disconnected. Locate the thermistor — on LG wall-mount units it’s a small sensor mounted near the front panel air intake. Unplug and re-seat the connector on the PCB. If the code persists, measure resistance (approximately 10 kΩ at 25°C) and replace if out of spec.
CH02: Indoor Pipe Thermistor Fault
The sensor mounted on the indoor coil has failed. Access requires opening the indoor unit cover. Re-seat the connector first; if the fault persists, replace the thermistor.
CH05: Communication Error
Indoor and outdoor units aren’t talking. On LG systems, communication travels on the 3-wire cable between units (typically labeled 1, 2, 3 or L1, N, S at the terminal block). Verify all three terminals are connected and tight. Also confirm the indoor/outdoor wire pairs are connected correctly — swapping signal and neutral is a common installation error.
CH33: High Pressure Protection
The system tripped the high-pressure safety cutout. Start by cleaning the outdoor unit coil — LG Dual Inverter models are particularly sensitive to dirty condenser coils. Use a garden hose and rinse from inside out to avoid pushing debris deeper. If the outdoor fan is running slowly or intermittently, CH38 may accompany CH33.
CH34: Low Pressure Protection
Low refrigerant charge or a refrigerant leak. The system needs professional diagnosis with gauges. Do not add refrigerant without first finding and repairing the leak.
CH44: Drain Float Switch
The drain pan is filling with water. Clear the condensate drain hose by vacuum or blowing compressed air through. LG wall-mount units use a gravity drain or an optional condensate pump — verify the pump (if present) is operational.
CH67: Inverter Compressor Fault
The inverter module detected a compressor fault. This can be a failing compressor, a shorted winding, or a faulty IPM (Intelligent Power Module) on the outdoor board. Compressor faults require professional diagnosis and typically result in replacement of the outdoor unit or compressor.
When to Call a Pro
CH67, CH25, CH32, CH34, and CH35 all require refrigeration technician-level expertise. Inverter compressor faults, refrigerant issues, and IPM failures are not user-serviceable items.