Dishwasher displays E09 and does not heat; cycles may run long and dishes come out cold and wet.

Safety first: Disconnect power and allow the dishwasher to cool completely before working on the heating system.

• Confirm no heating: Run a hot program and open the door mid‑cycle (after 20–30 minutes). If the interior is cold and there is no steam, the heater is not working.
• Inspect wiring and connectors: Remove the base cover and side panels. Check the wiring harness from the control board to the circulation pump/heater assembly for damage or burnt connectors. Repair or replace damaged sections.
• Test heater resistance: With a multimeter, measure resistance across the heater terminals. An open circuit indicates a failed heater.
• Check NTC sensor: Inspect the NTC sensor on the sump or heater housing. Ensure the connector is secure. A shorted or open NTC can cause the control to disable heating.
• Control board inspection: Remove the control module from the door. Visually inspect for burnt tracks or a damaged heater relay. If the relay is visibly burnt or the board smells burnt, the control board likely needs replacement.
• Replace faulty components: On most Grundig dishwashers, the heater is integrated with the circulation pump; replace the entire assembly if the heater is open. Replace the control board if the relay or board is damaged.
• Reassemble and test: Refit all parts, restore power, and run a hot program to verify proper heating and that E09 is cleared.