LG Heat Pump Error Code CH46

CH46 means the heat pump has detected a problem with the suction-pipe temperature sensor, which monitors refrigerant temperature on the suction side of the compressor circuit. The control board is receiving a signal that falls outside the expected range. The fault could be the thermistor itself, its wiring, or the connector. A technician will measure resistance and voltage at the sensor to pinpoint the cause.

Continuing to operate the unit with CH46 active is not recommended. The suction-pipe temperature sensor helps protect the compressor from liquid refrigerant slugging, and running without an accurate reading can cause compressor damage over time. It is best to stop using the unit until the sensor fault is diagnosed and resolved.

A reset may temporarily clear the code, but if the underlying sensor fault is still present, CH46 will return once the unit restarts and the control board re-evaluates the sensor signal. Resetting is useful only to confirm whether the fault is intermittent or persistent. A proper repair addressing the thermistor, connector, or wiring is needed to resolve the error permanently.

A knowledgeable DIYer can start by checking the sensor connector for looseness or visible corrosion and reseating it, which costs nothing. Testing the thermistor requires a multimeter: unplug the connector and measure resistance, looking for approximately 5k ohms at 25 degrees Celsius. If the sensor has failed or wiring is damaged, replacing those components is a more involved repair and working near refrigerant lines should be left to a certified technician.

If only the thermistor needs replacement, parts and labor typically range from around $100 to $250 depending on the model and local labor rates. If the wiring harness or control board is involved, costs can rise to the $300 to $700 range or more. Getting a diagnostic visit from a qualified technician will clarify the exact component at fault before committing to a repair.