LG Dishwasher Error Code bC3

The bC3 code indicates that communication between the main PBA and the sub PBA has failed for 24 consecutive seconds, or 4 seconds during Test Mode. The dishwasher's two control boards rely on a continuous data link to coordinate all functions, and when that link drops out long enough, the unit triggers this fault and stops operating. The root cause can be a loose connector, damaged wiring, or a failed board.

A power reset may temporarily clear the bC3 code if the communication failure was caused by a momentary glitch, but the code will return if there is an underlying hardware problem. If bC3 comes back after resetting, the physical connection and boards need to be inspected. Resetting alone is not a repair.

Repair costs depend on the root cause. If the issue is simply a loose or corroded connector, the cost is minimal, primarily covering the diagnostic labor. If a sub PBA or main PBA needs replacement, parts and labor combined can range from around $150 to $400 or more depending on the specific board and local labor rates. Getting a diagnostic visit first is the best way to estimate the actual repair cost.

A knowledgeable DIYer can start by checking the wiring harness connectors between the main PBA and sub PBA, as a loose connector is the most common cause and requires no parts. If the connectors are secure and the wiring appears undamaged, diagnosing and replacing a failed control board is more involved and typically benefits from technician-level experience with board identification and proper handling.

You should not continue running the dishwasher while bC3 is active. The error means the control boards cannot communicate, which prevents the appliance from properly managing its wash cycle, water levels, and motor functions. Operating the unit in this condition could lead to incomplete cycles or unintended behavior.