See also:

Resetting to factory settings
For safety reasons, the Daytime Running Lights: function in the Lights submenu is only reset when the vehicle is stationary. Press the or button on the steering wheel to select the Settin ...

Problems with the seat ventilation
The seat ventilation has switched off prematurely or cannot be switched on. The vehicle's electrical system voltage is too low because too many electrical consumers are switched on. - Switch ...

Additives
Only use DEF in accordance with ISO 22241. Do not use additives with DEF and do not dilute DEF with water. This may destroy the BlueTEC exhaust gas aftertreatment system. ...