LG Air Conditioner Error Code E506

E506 indicates that the LG air conditioner's self-diagnostic system has detected a fault with the low pressure sensor circuit. The control board monitors the signal from this sensor, which tracks refrigerant pressure on the suction side of the system. When the signal falls outside acceptable limits, E506 is triggered and the unit stops normal operation. The fault can stem from a wiring problem, a failed sensor, or an actual drop in refrigerant pressure.

No, you should not continue running the unit while E506 is active. The error indicates the system cannot reliably monitor low-side refrigerant pressure, which is a critical protection function. Operating without accurate pressure monitoring risks compressor damage from low refrigerant conditions. Keep the unit off until the fault is diagnosed and repaired.

Repair costs vary depending on the root cause. Replacing the low pressure sensor typically falls in the range of $75 to $200 including parts and labor. If the fault involves a refrigerant leak, expect costs between $150 and $500 or more depending on leak location and the amount of refrigerant needed. Control board replacement, if required, generally ranges from $200 to $600 including installation.

Some causes of E506 are DIY-accessible, such as reseating a loose sensor connector or inspecting the wiring harness for visible damage. However, testing voltage between pins 3 and 4 of the sensor connector requires a multimeter and basic electrical knowledge. Any work involving refrigerant, such as leak detection or recharging, must be performed by an EPA-certified technician and is not a DIY repair.

A power reset may temporarily clear the E506 code, but it will return if the underlying fault is still present. The unit's self-diagnostic routine will re-detect the sensor fault on the next startup or operating cycle. A reset should only be used after a repair has been made to confirm whether the fault has been resolved.