Dishwasher displays E03 and stops, usually during the wash or rinse phase; water may remain in the tub.

Safety first: Unplug the dishwasher or switch off the circuit breaker. Water inside may be hot.

• Confirm symptom: Run a short program and check if the water heats up at all (carefully feel the inner door or steam when opening mid‑cycle). Lack of heat supports a heating fault.
• Inspect wiring: Remove the lower front kick panel and side panels. Locate the circulation pump/heater assembly under the tub. Check all connectors for burning, looseness, or corrosion. Reseat them firmly.
• Check for leaks: Look for water traces around the heater and pump. Leaks can damage connectors and cause E03.
• Test heater resistance: With a multimeter and power disconnected, measure resistance across the heater terminals on the circulation pump. Typical values are 20–30 Ω. An open circuit or very low resistance indicates a failed heater.
• Check NTC sensor: Locate the NTC (temperature sensor) on the sump or heater housing. Inspect the connector and wiring. If accessible, measure its resistance at room temperature and compare with service specs; a short or open sensor must be replaced.
• Replace faulty parts: If the heater is integrated into the circulation pump (common on Grundig), replace the entire circulation pump/heater assembly. Ensure all seals and clamps are correctly fitted.
• Test cycle: Reassemble, restore power and water, and run a hot program to confirm normal heating and that E03 no longer appears.