Grundig range display shows d0, and oven functions are limited or disabled.

Safety first: No electrical hazard; this is a configuration issue.

• Exit demo mode: Refer to the user manual for your specific Grundig model. Commonly, press and hold a combination such as Function + Minus or Timer + Plus for several seconds until d0 disappears.
• Power reset: If unsure, switch off at the mains for 1 minute, then restore and try the demo-mode exit procedure again.

If you cannot exit demo mode, contact Grundig support with your exact model number for the correct key sequence.