Freezer displays E20 and may not enter or exit demo mode correctly; cooling may be disabled.

Safety: No internal electrical work is required for configuration changes, but unplug the unit if removing panels.

Steps:

• 1. Check for demo mode: Consult the Neff user manual for your model to identify the key combination to toggle demo mode. Commonly, holding specific buttons for several seconds will exit demo mode.
• 2. Perform reset: Unplug the freezer for 10 minutes, then reconnect and immediately perform the demo mode exit procedure.
• 3. UI function check: Ensure all buttons respond correctly. If some buttons do not work, the UI board may be faulty and require replacement.
• 4. Control module replacement: If the appliance cannot exit demo mode despite correct procedure and working buttons, the configuration memory in the main control module may be corrupted. Replace the module with a genuine Neff part.