Opening the DEF filler cap

The filler neck for DEF is behind the fuel filler flap.

The fuel filler flap is unlocked or locked automatically when you open or close the vehicle with the SmartKey or with KEYLESSGO.

- Switch off the ignition.

- Switch off the ignition.
- Press the fuel filler flap in the direction of arrow 1.
The fuel filler flap swings up.
- Turn blue DEF filler cap 2 counterclockwise and remove it.
DEF filler cap 2 is secured with a plastic strap.

    See also:

    Resetting triggered NECK-PRO head restraints
    WARNING For safety reasons, have the NECK-PRO head restraints checked at an authorized Mercedes-Benz Center after a rear-end collision. WARNING When pushing back the NECK-PRO head r ...

    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 wor ...

    General notes
    USA only: This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: 1. This device may not cause harmful interference, and 2. this device must a ...