E04 appears and the machine stops mid-brew; sometimes accompanied by unusual pump noise.

Safety first: Switch off and unplug the coffee maker before handling the water tank.

• Refill and reseat tank: Fill the Kenwood water tank above the MIN level and push it firmly into place. Make sure the bottom valve opens when seated.
• Prime the pump: After refilling, plug the machine back in. If your model has a hot-water or steam function, run it for 20–30 seconds to draw water through the system and remove air.
• Check for blockages: Inspect the tank outlet for debris or scale. Clean with a soft brush and warm water. Ensure the small rubber valve at the bottom of the tank moves freely.
• Descale the hydraulic circuit: Run a full descaling cycle to remove internal scale that can cause pump overload.
• If E04 recurs frequently: The ULKA pump or its internal check valve may be worn. Replacement of the pump assembly is recommended and should be done by a technician.