LG Dishwasher Error Code AC2

The AC2 error code means the main control board (Main PBA) has not received a response from the inverter control board (Inverter PBA) within 3 seconds. This applies to units with software version 7134 and above. The dishwasher responds by cutting power to the inverter for one minute and then retrying the connection automatically. It most commonly points to a wiring or connector issue between the two boards.

Running the dishwasher while the AC2 error is active is not recommended. The inverter board controls the wash motor, and operating with a communication failure between the boards could result in further damage to the motor or control electronics. The unit's built-in retry cycle is a protective measure, not a permanent workaround, so the underlying issue should be diagnosed and repaired before regular use resumes.

Repair costs depend on the root cause. If the fix involves reseating a connector or cleaning contacts, a service call labor charge of roughly $80 to $150 may be all that is needed. Replacing a failed inverter PBA typically adds $100 to $250 or more for the part depending on the model. Replacing the main control board can bring the total cost higher, often in the range of $200 to $400 including labor, making it worth comparing against the age and value of the appliance.

If you are comfortable working with appliance electronics, you can start by checking the CN1 connector between the Main PBA and the Inverter PBA for secure seating and visible pin damage. Reconnecting a loose harness or cleaning corroded contacts is within reach for a knowledgeable DIYer. However, if the fault points to a failed inverter board or main control board, replacing those components typically requires a technician familiar with LG dishwasher service procedures.

A reset may temporarily clear the error code from the display, but it will return if the underlying communication fault between the Main PBA and Inverter PBA has not been resolved. The dishwasher's own firmware already performs automatic retry cycles as part of the AC2 fault response. A reset alone is not a fix and should be followed by a proper diagnostic inspection of the CN1 connectors and wiring harness.