LG Air Conditioner Error Code 143

Error code 143 means the high pressure sensor on the sub1 outdoor unit detected an excessive rise in refrigerant pressure and commanded the compressor to shut off. This is a protective lockout designed to prevent damage to the compressor and refrigerant circuit. The system will not restart normally until the cause of the high pressure condition is identified and corrected.

No, you should not attempt to force the system to run while error 143 is active. The compressor has been shut off by the control system to prevent damage from excessive pressure. Continuing to operate the unit under high pressure conditions could cause compressor failure or refrigerant circuit damage, leading to significantly higher repair costs.

Repair costs vary widely depending on the root cause. Cleaning the condenser coil is typically on the lower end, ranging from around $75 to $200 for a service visit. Replacing a condenser fan motor or high pressure sensor generally falls in the $150 to $400 range including parts and labor. If the compressor has sustained damage from repeated high pressure events, costs can climb significantly higher.

Some causes of error 143 can be addressed without a technician, such as opening a closed service valve or cleaning a blocked outdoor condenser coil. However, diagnosing refrigerant overcharge or a faulty pressure sensor requires manifold gauges and refrigerant handling certification. If basic checks do not resolve the issue, a licensed HVAC technician should be called in.

A power reset may temporarily clear the fault and allow the compressor to restart, but if the underlying high pressure condition has not been resolved, the unit will lock out again and the 143 code will return. Resetting without diagnosing and fixing the root cause is not a permanent solution and risks repeated compressor shutdowns.