Diagnosis
Error code E15 indicates a water leak has been detected. The leak sensor (float switch) in the base of the tub has been triggered.
How to Fix It
Immediately cancel the cycle and disconnect power. Remove the bottom rack. Inspect the entire tub interior, door seal, and base for standing water. Use towels to dry everything thoroughly. Check the drain hose connection under the sink for tightness. Clear any debris from around the door gasket. After everything is dry, restore power.
If That Didn't Work
The leak sensor itself may be stuck in the triggered position. Locate the white plastic sensor housing in the base of the tub (under the filter). Gently press down on the float to ensure it moves freely and is not obstructed.
Heads Up
The E15 code is a safety feature. The dishwasher will not operate until the sensor is dry and the error is cleared by a power cycle. Persistent E15 without visible water points to a sensor fault.