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:

    Exterior
    The E-Class was redesigned for 2010, and I'm not a huge fan of the new look. It trades the rounded edges and quad headlights I liked from the previous model for a more angular, sharper look. It bl ...

    Overinflated tires
    WARNING Follow recommended tire inflation pressures. Do not overinflate tires. Overinflated tires can adversely affect handling and ride comfort, wear unevenly, increase stopping distance, a ...

    Engine
    Display messages Possible causes/consequences and Solutions The yellow Check Engine warning lamp lights up while the engine is running. There may be a malfunction, for ex ...