See also:

System self-test
After you have switched on the ignition, the system carries out a self-diagnosis. WARNING A malfunction in the system has been detected if one of the following conditions occurs:  - ...

Cleaning the headliner and carpets
Roof lining: use soft brushes or dry shampoo if it is particularly dirty. Carpets: use carpet and textile cleaners that have been approved and recommended by Mercedes-Benz. ...

Cleaning the steering wheel and gear or selector lever
– Thoroughly wipe with a damp cloth or use leather care agents that have been recommended and approved by Mercedes- Benz. ...