Machine displays E05 and will not brew; often occurs after a descaling or cleaning cycle.

Safety first: Unplug the appliance and allow it to cool completely before accessing internal components.

Step-by-step:

• 1. Power reset: Disconnect from mains for 5–10 minutes, then reconnect and test. Temporary sensor glitches can sometimes be cleared.
• 2. Run a full descale: If not recently done, run the Siemens descaling program. Pay attention to the steam/hot-water steps to ensure the steam circuit is flushed thoroughly.
• 3. Check steam outlet: Remove and clean the milk frother or steam nozzle. Blocked outlets can cause abnormal temperatures and trigger E05.
• 4. Inspect sensor wiring (advanced): With the cover removed, locate the steam thermoblock and its NTC sensor. Ensure the sensor is firmly attached to the block and that its connector is secure on the control board.
• 5. Professional service: If E05 remains, the steam NTC or control board likely needs replacement. Due to the risk of steam leaks and electrical hazards, this repair is best left to Siemens service.