LG Air Conditioner Error Code CH43

CH43 indicates that the high pressure sensor circuit has been detected as open or shorted by the control board. The high pressure sensor monitors refrigerant pressure on the discharge side of the compressor. Because the system cannot verify safe operating pressure, it shuts down to protect the compressor. The fault can be caused by a failed sensor, damaged wiring, or a loose connector.

No. The system generally shuts down when CH43 is active precisely because it cannot monitor high-side refrigerant pressure. Running the unit without a functioning high pressure sensor risks compressor damage from undetected over-pressure conditions. The unit should remain off until the fault is diagnosed and repaired.

A power reset may temporarily clear the fault code, but if the underlying sensor or wiring problem is still present, CH43 will return quickly once the system restarts and re-checks the sensor circuit. Resetting without repairing the root cause does not fix the problem and can delay a proper diagnosis. The fault must be corrected at the component level for the error to stay cleared.

Checking connectors for looseness and inspecting visible wiring for damage are steps a knowledgeable DIYer can perform. However, measuring sensor output voltage and working near refrigerant components typically requires proper tools and, in many regions, certification to handle refrigerants. If the sensor or any refrigerant-side component needs replacement, a licensed technician should complete the repair.

If only the high pressure sensor needs replacement, parts and labor typically range from around $150 to $350 depending on the model and your location. If the control board is involved, costs can range from $300 to $600 or more. A service call for diagnosis alone usually runs $75 to $150, which is often applied toward the repair cost.