LG Washer Error Code AC

The AC error code on an LG washer indicates a communication error between the sub PCB and the main PCB. These two control boards must continuously exchange signals during operation, and when that communication is lost, the washer shuts down and displays AC. The problem is most often traced to a loose, corroded, or damaged connector between the two boards.

No, you should not continue to use the washer while the AC error is active. The code indicates the control boards cannot communicate, meaning the machine cannot reliably manage its functions. Running the washer in this state could result in unpredictable behavior or further component damage.

Repair costs vary depending on the underlying cause. If only a connector needs to be re-seated, the cost is minimal and may just be a diagnostic service fee in the range of $75 to $150. Replacing a wiring harness typically runs $100 to $250 in parts and labor. A PCB replacement is the most expensive scenario, with costs ranging from $200 to $500 or more depending on which board has failed.

In many cases, yes. Start by unplugging the washer and carefully inspecting the wiring harness connectors between the sub PCB and main PCB for loose or improperly seated connections. Re-seating connectors and checking for damaged wiring are repairs a knowledgeable DIYer can perform. If the boards themselves have failed, replacing a PCB is more involved and may be better suited to a qualified technician.

A reset, performed by unplugging the washer for a few minutes and then restoring power, may temporarily clear the error if a minor signal glitch caused it. However, if there is an actual physical problem with a connector, wiring harness, or PCB, the code will return. A reset is a reasonable first step but is not a substitute for a proper inspection.