Dishwasher shows E12; water may be present but temperature readings are incorrect, causing poor wash performance.

Safety first: Disconnect power and allow the dishwasher to cool.

• Locate NTC sensor: The temperature sensor (NTC) is typically mounted in the sump or on the tub base. Access from inside the tub or from underneath, depending on model.
• Inspect connection: Check the NTC connector for corrosion or looseness. Clean and reseat as needed.
• Test sensor: Remove the NTC and measure its resistance at room temperature. Compare to Summit service specifications; a reading far out of range indicates a bad sensor.
• Replace NTC: Install a new temperature sensor if faulty. Ensure the sealing grommet is properly seated to prevent leaks.
• Check harness and board: If the NTC is good, inspect the wiring to the main control board and the board itself for damage. Replace the board if necessary.