Mercedes-Benz M-Class Operator's Manual page 156

Refueling
154
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 KEYLESS-
GO.
Switch off the ignition.
X
Press the fuel filler flap in the direction of
X
arrow :.
The fuel filler flap swings up.
Turn blue DEF filler cap ;
X
counterclockwise and remove it.
DEF filler cap ; is secured with a plastic
strap.
DEF refill bottle
DEF refill bottles can be obtained at many gas
stations or at an authorized Mercedes-Benz
Center. Refill bottles without a threaded cap
do not provide overfill protection. DEF may
leak if overfilled. Mercedes Benz provides
special refill bottles with threaded caps.
These are available at any authorized
Mercedes-Benz Center.
Unscrew the protective cap from DEF refill
X
bottle :.
Place DEF refill bottle : on the filler neck
X
as shown and screw it on clockwise until it
is hand-tight.
!
Only screw on the DEF refill bottle hand-
tight. It could otherwise be damaged.
Press DEF refill bottle : in the direction of
X
the filler neck.
The DEF tank is filled. This may take up to
one minute.
i
When DEF refill bottle : is no longer
pressed, filling stops and the bottle may be
taken off again after being only partially
emptied.
Release DEF refill bottle :.
X
Turn DEF refill bottle : counterclockwise
X
and remove it.
Screw on the cover of DEF refill bottle :
X
again.
I n f o r ma t i o n P r o v i d e d b y :