Diagnosis
Debris is jammed in the drain pump impeller. Common culprits are broken glass, olive pits, or plastic fragments.
How to Fix It
Unplug the dishwasher. Remove the lower kick plate. Locate the drain pump housing at the bottom front. You'll see a small hex-head impeller cover. Use a 1/4" drive socket to turn it counterclockwise and remove it. Reach in with needle-nose pliers to clear any obstruction.
If That Didn't Work
The drain pump motor itself may have failed. If the impeller spins freely by hand but the motor hums, the pump is seized. You must replace the entire drain pump assembly, part number WPD8701297.
Heads Up
Always scrape plates thoroughly. A fine mesh sink strainer is not enough. Check for and remove any broken glass from the tub before running another cycle.