See also:

Releasing the parking brake manually
In the event of an electrical power loss or electrical malfunction, you can release the parking brake manually. Secure the vehicle against rolling Before releasing the parking brake manually, ...

Malfunction
A message is displayed. Adaptive light control is malfunctioning or has failed. Have the system checked as soon as possible. ...

Functional readiness of the airbagsystem
When the ignition is switch on, the warning lamp in the instrument cluster lights up briefly and thereby indicates the operational readiness of the entire airbag system and the belt tensioner. ...