LG Air Conditioner Error Code 01

Error code 01 on an LG air conditioner indicates that the indoor unit air temperature sensor has been detected as either open or shorted by the control board. The sensor is an NTC thermistor that monitors return air temperature, and when its signal falls outside the acceptable range, the system logs this fault and stops normal operation. The first step is to check whether the sensor connector is properly seated on the PCB, then measure the sensor resistance if the connection is secure.

It is not recommended to continue running the unit while error code 01 is active. The control board relies on the air temperature sensor to regulate the system properly, and operating without a valid temperature reading can lead to inefficient performance or potential damage to other components. The unit may refuse to operate at all once the fault is detected, which is a built-in protection feature.

A power reset may temporarily clear the error display, but if the underlying sensor fault is still present, the code will return once the unit restarts and the control board re-evaluates the sensor signal. A reset alone is not a repair. The sensor connection and sensor resistance must be properly diagnosed and corrected to resolve the fault permanently.

A knowledgeable DIYer can begin by checking if the sensor connector has come loose at the indoor PCB and reseating it firmly. If the error persists, testing the sensor resistance with a multimeter requires disconnecting the sensor and comparing the reading to the expected value for the ambient temperature. Replacing the sensor itself is a relatively straightforward repair, but working inside the indoor unit involves electrical components, so those without comfort doing so should call a technician.

If the fix is simply reseating a loose connector, there is no parts cost involved. A replacement indoor air temperature sensor typically costs between $10 and $40 depending on the specific unit model. If the indoor PCB itself needs to be replaced due to a damaged sensor input circuit, the part and labor costs combined can range from $150 to $400 or more.