Display shows 'd' or 'demo' and zones heat only very weakly or not at all

Steps to exit demo mode (typical AEG procedure – refer to manual for exact sequence):

• Switch the hob off using the main power key.
• Press and hold the lock key and a specific cooking zone key simultaneously for several seconds (varies by model).
• Look for 'd' or 'demo' to disappear from the display and a confirmation beep.
• If unsure, consult the AEG user manual for your exact model number and follow the documented demo mode deactivation steps.

If demo mode cannot be cleared, the control PCB may have a configuration fault and should be checked by an AEG technician.