See also:

Purity
Assuring the purity of DEF is particularly important with respect to avoiding malfunctions in the exhaust gas aftertreatment system. If DEF is pumped out of the DEF tank, e.g. during repair wor ...

Reporting malfunctions relevant to safety
For the USA only: The following text is reproduced as required of all manufacturers according to Title 49, Code of U.S. Federal Regulations, Part 575 pursuant to the National Traffic and Moto ...

Activating/deactivating airrecirculation mode
You can deactivate the flow of fresh air if unpleasant odors are entering the vehicle from outside. The air already inside the vehicle will then be recirculated. The operation of air-recirculat ...