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.

Impurities in DEF (e.g. due to other 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:

    Slippery road surfaces
    WARNING   The outside temperature indicator is not designed to serve as an ice-warning device and is therefore unsuitable for that purpose. Indicated temperatures just above the freezin ...

    Installing/removing the towing eye
    Installing the towing eye •► Remove the towing eye from the vehicle tool kit WARNING The exhaust tail pipe may be hot. You could burn yourself if you touch the tail pipe. Be particu ...

    Towing the vehicle with the rear axle raised
    Only possible on vehicles without 4MATIC. When towing your vehicle with the rear axle raised, it is important that you observe the safety instructions (). The ignition must be switched off if y ...