LG Air Conditioner Error Code 35

Error code 35 means the outdoor unit experienced a low refrigerant pressure condition that caused the compressor to shut off three successive times. The low pressure sensor detected a pressure drop below the acceptable threshold on each restart attempt, triggering a protective lockout. This prevents the compressor from running in a condition that could cause serious mechanical damage. A technician should diagnose the root cause before the unit is restarted.

No. Error code 35 is a protective lockout and the unit will not run while this fault is active. Attempting to force the system to operate with low refrigerant pressure can cause the compressor to overheat and fail. Allow the system to remain off and have it inspected before resuming normal operation.

Repair costs vary depending on the cause. If the fix is simply opening a closed service valve, you may only pay a diagnostic service fee, typically in the range of $75 to $150. If the system needs refrigerant recharge and a leak repair, costs commonly range from $200 to $600 or more depending on refrigerant type and leak location. Replacing components like an expansion valve or low pressure sensor can add $150 to $400 in parts and labor.

The first step, checking whether the outdoor unit service valves are fully open, is something a knowledgeable DIYer can do without special tools. However, if the valves are open and the error persists, diagnosing low refrigerant charge, a faulty sensor, or a restricted expansion valve requires refrigerant gauges, EPA certification for handling refrigerant, and electrical diagnostic equipment. Those repairs should be handled by a licensed HVAC technician.

A power reset may clear the fault temporarily and allow the unit to attempt to restart, but if the underlying cause is not corrected, the compressor will shut down again and the error will return. Because this code requires three consecutive shutdowns to trigger, repeated resets without fixing the root cause risk additional stress on the compressor. Address the cause first rather than relying on resets.