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:

    Important safety notes
    ATTENTION ASSIST helps you during long, monotonous journeys such as on freeways and interstate highways. It is active in the range between 50 mph (80 km/h) and 112 mph (180 km/h). If ATTENTIO ...

    Instruction labels for tires and loads
    WARNING Do not overload the tires by exceeding the specified load limit as indicated on the Tire and Loading Information placard on the driver's door B-pillar. Overloading the tires can ove ...

    Displaying service messages
    •► Switch on the ignition. •► Press on the steering wheel to select the Serv. menu. •► Press to select the ASSYST PLUS submenu and press to confirm. The service due date ap ...