Machine attempts to brew but stops quickly; pump noise is weak or absent and E03 is displayed.

Safety first: Unplug the machine before removing the water tank or accessing internal parts.

• Check water tank outlet: Remove the tank and inspect the outlet valve for debris or coffee grounds. Rinse thoroughly and ensure the valve moves freely.
• Bleed air from the system: Fill the tank completely with water, reinstall, then plug in the machine. Start a hot water or rinse cycle (if available) without coffee. If the pump is noisy and sputtering, let it run for 30–60 seconds to purge air.
• Descale the hydraulic circuit: Mineral buildup can restrict flow and trigger E03. Run a full descaling cycle following the Grundig manual, then flush with fresh water.
• Check for kinks in the tank connection: Ensure the tank is fully seated and not deforming the inlet hose or seal.
• Service required: If there is no pump sound at all or E03 persists after descaling and bleeding, the ULKA pump or flow meter may be defective and should be replaced by a technician.