Display shows E2 and the Klarstein coffee maker stops heating or will not start brewing.

Safety first: Unplug the coffee maker and let it cool for at least 30 minutes before opening any panels.

Basic checks:

• Power reset: Disconnect the machine from mains for 5 minutes, then reconnect and test. Transient faults can sometimes clear.
• Check for scale buildup: Heavy limescale on the heating block can cause abnormal temperature readings. Run a full descaling cycle with Klarstein-approved descaler or a citric-acid-based product following the user manual.

Sensor inspection (advanced):

• Remove the bottom or rear cover to access the aluminum heating block or stainless steel boiler.
• Locate the small NTC thermistor clipped or screwed to the heater body (usually with two thin wires).
• Check that it is firmly attached and not hanging loose. Reattach with the original clip or a high-temperature clamp if needed.
• Inspect the connector to the main PCB; unplug and replug to clean the contacts.
• If you have a multimeter, measure the thermistor resistance at room temperature and compare with the service spec (commonly 50–100 kΩ at 25°C). Infinite or near-zero resistance indicates a failed sensor.

If the thermistor is defective, replace it with a Klarstein-compatible NTC sensor of the same rating. If you are not comfortable working around mains wiring, contact a qualified technician.