Machine shows E19 and may not switch correctly between coffee and steam functions.

Safety first: Unplug the machine and allow it to cool before accessing internal valves.

Step-by-step:

• 1. Descale the machine: Run a complete descaling cycle to dissolve scale inside the diverter valve and connected pipes.
• 2. Exercise the valve: After descaling, repeatedly switch between coffee, hot water, and steam functions to move the valve through its positions.
• 3. Listen for valve click: During function changes, listen for a distinct clicking sound from the diverter valve. No click may indicate a failed solenoid or no power.
• 4. Advanced inspection: Remove the side panel to locate the diverter valve. Check electrical connectors and look for signs of leakage or scale.
• 5. Professional replacement: If E19 persists, the diverter valve assembly or its coil likely needs replacement by a Siemens technician.