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:

    Locking the vehicle (mechanical key)
    If the vehicle can no longer be locked with the SmartKey, use the mechanical key. •► Open the driver's door.•► Close the front-passenger door, the rear doors and the trunk lid/tailgat ...

    The M-Class also protects its occupants after a crash
    As part of the POST-SAFE® functions, the new M-Class can activate a variety of systems which can contribute towards avoiding post-accident risks. After a more serious crash, the hazard warning lig ...

    Selecting the ideal shift range
    Pull the left-hand steering wheel paddle shifter and hold it in position. The automatic transmission shifts to the gear which allows optimum acceleration and deceleration. To do this, the auto ...