LG Air Conditioner Error Code 70

Error code 70 on an LG air conditioner means the CT (current transformer) sensor on the constant speed compressor circuit has been detected as open or shorted. The CT sensor is responsible for monitoring compressor current, and when its circuit fails, the unit shuts down to prevent operating the compressor without current feedback protection. The fault can originate in the sensor wiring, the connector, or the sensor itself.

No. The unit will typically shut down and refuse to operate normally when error code 70 is active, because the CT sensor provides overcurrent protection for the compressor. Attempting to bypass or ignore this fault and force the unit to run without functional current monitoring could allow an overloaded or faulting compressor to operate undetected, potentially causing compressor damage or an electrical hazard.

A power reset may temporarily clear the error and allow the unit to attempt operation, but if the CT sensor circuit is genuinely open or shorted, the fault will return quickly once the control board rechecks the sensor signal. A reset alone does not repair the underlying wiring or sensor fault. The code will continue to reappear until the defective component or connection is physically repaired or replaced.

Some basic checks, like reseating a loose wiring connector at the CT sensor, are within reach for a handy homeowner. However, diagnosing an open or shorted CT sensor circuit accurately requires a multimeter and familiarity with reading wiring diagrams. Work involving the compressor circuit carries electrical hazard risk, so if you are not comfortable working around high-voltage components, a licensed HVAC technician should perform the diagnosis and repair.

Repair cost depends on the root cause. If the fix is simply reseating a connector or repairing a section of damaged wiring, labor costs may be in the range of $75 to $200. Replacing the CT sensor itself typically adds $20 to $80 in parts. If the control board has failed, expect parts and labor to range from $250 to $600 or more depending on the model.