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 work, it must not be returned to the tank. The purity of the fluid can no longer be guaranteed.

service products, cleaning agents or dust) Impurities in DEF (e.g. due to other service products, cleaning agents or dust) lead to:
• increased emission values
• damage to the catalytic converter
• engine damage
• malfunctions in the BlueTEC exhaust gas aftertreatment system

    See also:

    Safety systems
    Display messages Possible causes/consequences and Solutions Risk of accidentThe brake boosting effect is malfunctioning and the braking characteristics may be affec ...

    Important safety notes
    The rear view camera is an optical parking and maneuvering aid. It shows the area behind your vehicle with guide lines in the COMAND display. WARNING Make sure that no persons or animals are ...

    Windows fogged up on the outside
    - Activate the windshield wipers. - Press the button repeatedly until the or symbol appears in the display. You should only select this setting until the windshield is clear again. ...