LG Heat Pump Error Code P432

P432 on an LG heat pump indicates that cooling mode operation is being blocked because the outdoor temperature has been detected as being below -5°C (23°F). This is a built-in protective restriction, not a component failure. The unit will not run in cooling mode under these conditions by design. If the outdoor temperature is actually above -5°C, the outdoor temperature sensor should be checked for accuracy.

P432 itself is not a safety hazard. It is a protective feature that prevents the system from running the refrigerant circuit in cooling mode during very cold outdoor conditions. The restriction is intentional and keeps the unit from operating outside its designed temperature range. If you suspect the code is appearing due to a faulty sensor rather than actual cold temperatures, addressing the sensor issue is straightforward and low risk.

Resetting the unit may temporarily clear the P432 display, but the code will return if the outdoor temperature is still below -5°C or if the underlying sensor issue has not been resolved. Because P432 is a condition-based restriction rather than a latched fault, the control board will reinstate the cooling lockout as soon as it reads a temperature below the threshold. A permanent fix requires either waiting for warmer weather or correcting the sensor or wiring problem causing the inaccurate reading.

Start by verifying the actual outdoor temperature with a thermometer near the outdoor unit and compare it to the temperature reading shown by the system. If the outdoor temperature is genuinely below -5°C, no fix is needed as the unit is working correctly. If temperatures are above -5°C but the code persists, inspect the outdoor ambient temperature sensor, its wiring, and the connector at the control board for damage, corrosion, or loose connections. Replace the sensor if its resistance reading does not match the expected value for the current temperature.

If the code is appearing because outdoor temperatures are genuinely below -5°C, there is no repair cost at all. If a faulty outdoor ambient temperature sensor is the cause, sensor replacement parts typically range from around $20 to $80 depending on the specific model, plus labor if a technician is involved. Wiring repairs, if needed, are usually lower in cost than sensor replacement.