Dishwasher displays C6; wash performance is poor and water may not heat properly.

Safety: Turn off power at the breaker before accessing the base or wiring. Water in the tub may be hot.

• Verify hot water supply: Run hot water at the sink until it is hot before starting the dishwasher. Monogram units rely on incoming hot water to reach proper temperature.
• Check heater element visually: Remove the lower rack and inspect the exposed heater (if visible) for breaks, heavy scale, or burn marks.
• Access heater terminals: From beneath the dishwasher, locate the heater terminals passing through the tub. Check for loose or burned connectors.
• Test heater resistance: With power disconnected, use a multimeter to measure resistance across the heater terminals. An open circuit (infinite resistance) indicates a failed element.
• Inspect thermistor/temperature sensor: Some models use a thermistor in the sump. Check its wiring harness for damage or corrosion.

If the heater is open or physically damaged, replace it with the correct Monogram heater assembly. If heater and sensor test good, the control board may not be energizing the heater and should be evaluated by a professional.