LG Air Conditioner Error Code CH01

CH01 indicates an indoor air temperature sensor error on LG air conditioners. The fault is triggered when the indoor PCB detects an abnormal signal from the return air thermistor, which can be caused by a disconnected connector, a failed sensor, or a faulty PCB. The sensor should read 10KΩ resistance at 25 degrees Celsius when unplugged, or approximately 2.2Vdc when connected and measured at the PCB with the unit powered.

Operating the unit with an active CH01 fault is not recommended. Without a valid temperature reading from the indoor air sensor, the system cannot regulate itself correctly, which can lead to improper cycling, overcooling, or compressor stress. It is best to resolve the fault before resuming normal use.

If only the sensor needs replacement, parts and labor typically fall in the range of $75 to $200 depending on the model and local labor rates. If the indoor PCB is the root cause, the repair cost can range from $200 to $500 or more, since PCBs are significantly more expensive than sensors. Getting a diagnostic visit from a technician before purchasing parts is a good way to avoid unnecessary expenses.

Checking and reseating the sensor connector is a straightforward task that a careful homeowner can perform after unplugging the unit from power. Measuring resistance and voltage requires a multimeter and some comfort with electrical testing. If the PCB needs replacement, most homeowners prefer to have a qualified technician handle that repair due to the cost of the part and the precision required during installation.

Powering the unit off and back on may temporarily clear the code, but CH01 will return if the underlying problem has not been corrected. A loose connector that reseats itself during handling might stay clear after a reset, but a failed sensor or damaged PCB will trigger the fault again once the unit restarts and checks the sensor signal.