LG Air Conditioner Error Code 46

Error code 46 on an LG air conditioner indicates a fault with the outdoor unit suction temperature sensor. The control board has detected either an open circuit or a short circuit in that sensor, meaning the resistance signal is outside the expected range. The system uses this sensor to monitor refrigerant temperature at the outdoor unit suction line, and without a valid reading it may limit or stop compressor operation to protect internal components.

Operating the unit while error code 46 is active is not recommended. The suction temperature sensor provides data the system uses to protect the compressor from liquid refrigerant slugging and other damaging conditions. Without a valid sensor signal, the control board cannot make accurate decisions about compressor operation, which could lead to compressor damage over time. It is best to address the fault before resuming normal use.

A power reset may temporarily clear the error code, but if the underlying sensor, wiring, or connector issue is still present, the fault will return once the system runs and checks the sensor signal again. Resetting without diagnosis does not fix the root cause. A proper repair requires inspecting the connector, measuring sensor resistance, and addressing any failed component before the code will stay clear.

Some steps are accessible to a knowledgeable DIYer, such as inspecting the sensor connector at the outdoor unit PCB for looseness or corrosion and reseating it. Measuring the sensor's resistance with a multimeter and comparing it to the expected value for the current temperature is also feasible if you are comfortable working with electronics. However, if the sensor or wiring needs replacement, or if the outdoor PCB is suspect, a qualified technician should handle those repairs, especially since the outdoor unit contains high-voltage components.

Repair costs depend on the root cause. If only a connector needs cleaning or reseating, the cost is primarily a service call fee, which typically ranges from around $75 to $150. If the suction temperature sensor itself needs replacement, parts and labor together generally range from $100 to $250. If the outdoor PCB is the cause, costs can increase significantly, potentially ranging from $200 to $500 or more depending on the model and labor rates in your area.