
Problems with the fuel and fuel tank
If your vehicle is losing fuel, the fuel lines or thefuel tank are defective.
XTurn the key immediately to position 0in the
ignition lock and remove it.
XDo not restart the engine under any circum-
stances.
XConsult a qualified specialist workshop.
If the fuel tank has been run dry, after refueling
carry out the following steps:
XBefore starting the engine: switch on the igni-
tion three or four times.
XTurn the key to position 2in the ignition lock
(Ypage 119).
The % preglow indicator lamp in the instru-
ment cluster lights up briefly.
XOnce the %preglow indicator lamp goes
out, turn the key to position 3in the ignition
lock and release it as soon as the engine is
running.
You can start the diesel engine without preglow
when the engine is warm.
Diesel Exhaust Fluid (DEF)
Important safety notes
!Only use DEF in accordance with
ISO 22241. Never mix DEF with additives or
thin it with tap water. The exhaust gas after-
treatment may otherwise be damaged.
Observe the MB Specifications for Service
Products, Sheet 352.0.
Damage that results from the use of additives
or tap water leads to the loss of the New
Vehicle Limited Warranty.
!If DEF comes into contact with a painted or
aluminum surface, wash the surface off
immediately with plenty of water.
!DEF is not a diesel additive and must not be
mixed with fuel in the tank. Even small
amounts of DEF can cause engine damage.
Damage that results from the blending of DEF
will not be covered by the New Vehicle Limi-
ted Warranty.
iIf the outside temperature is below 12 ‡
( Ò 11 †) it may be difficult to top up. If the DEF
is frozen and there is an active warning indi- cator, topping up may not be possible. Park
the vehicle in a warm place, e.g. in a garage,
until the DEF has become liquid again. Top-
ping up is then possible again. Alternatively,
have the DEF tank refilled at a qualified spe-
cialist workshop.
iIf you add DEF at temperatures below 12 ‡
( Ò 11 †) it is possible that the level is not
shown correctly due to the frozen DEF.
Drive for at least 20 minute s(heating phase in
the tank activated) and then st
op the vehicle
for at least 30 seconds. The level is then
shown correctly.
You will find further information on DEF in the
"Service products" section (
Ypage 278).
Refueling procedure
DEF filler neck
Non-lockable DEF filler cap
Example: DEF filler cap in the engine compartment
XTo open: switch off the ignition.
XOpen the hood (Ypage 219).
XTurn filler cap :counter-clockwise and
remove it.
XTo close: replace cap :on the filler neck and
turn it clockwise.
You will hear a click when cap :is fully
closed.
XClose the hood (Ypage 220).
128Refueling
Driving and parking

Diesel Exhaust Fluid(DEF)
Vehicles wit hpassenger vehicle approva l
Display messagesPossible causes/consequences an dMSolutions
dEF ChkIn addition ,th eyello wå DEFindicator lamp lights up in th einstru-
men tcluster and awarnin gtone sounds.
The DE Fsupply has dropped belo w1.5US gal (5.5l).
XAdd DEF supply (Ypage 128).
The å DEF indicator lamp only disappears when the vehicle is
stationary, at the latest after 20 secondsa s soon as you switch on
the ignition or start the engine after refueling.
In addition, the yellow ;Check Engine indicator lamp and the yel-
low å DEF indicator lamp light up in the instrument cluster and a
warning tone sounds.
The DEF reducing agent is contaminated, diluted or is not compliant
with ISO 22241.
XHave the DEF tank cleaned and refilled at a qualified specialist
workshop as soon as possible.
StArtS RExxIn addition, the yellow åDEF indicator lamp lights up and a warning
tone sequence sounds.
The DEF supply has dropped below the 0.8 US gal (3.0 l) reserve mark.
After the message appears for the first time, the remaining DEF supply
will last for approximately 1200 miles (1900 km). The engine can then
only be started another 16 times.
The number of remaining engine starts XX
(16to1) is shown in the
message every time the engine is started.
XAdd at least 1.5 US gal (5.5 l) of DEF (Ypage 128).
The å DEF indicator lamp only disappears when the vehicle is
stationary, at the latest after 20 seconds as soon as you switch on the ignition or start the engine after refueling.
In addition, the yellow ;Check Engine indicator lamp and the yel-
low å DEF indicator lamp light up in the instrument cluster and
three short warning tones sound.
The DEF reducing agent is contaminated, diluted or is not compliant
with ISO 22241.
The exhaust gas aftertreatment is malfunctioning or an emission rel-
evant malfunction has occurred. This malfunction or defect can dam- age the exhaust gas aftertreatment.
XVisit a qualified specialist workshop immediately.
Display messages177
On-board computer and displays
Z

Display messagesPossible causes/consequences andMSolutions
¯
StArtS IdLE
In addition,th eyellow åDEFindicator lamp and th e; Check
Engin eindicator lamp ligh tup in th einstrumen tcluste rand three
warning tone ssound.
If th eStArtS
IdL Emessage is displayed, you canno tdrive th evehicl e
at aspeed of mor ethan 5mph (8 km/ h).
XAdd at least 1.5 US gal (5.5 l) of DEF (Ypage 128).
The å DEF indicator lamp only disappears when the vehicle is
stationary, at the latest after 20 secondsa s soon as you switch on
the ignition or start the engine after refueling.
In addition, the yellow ;Check Engine indicator lamp and the yel-
low å DEF indicator lamp light up in the instrument cluster and a
warning tone sounds.
You cannot drive the vehicle at a speed exceeding 5 mph (8 km/h).
XVisit a qualified specialist workshop immediately.
Vehicles with commercial vehicle approval
Display messagesPossible causes/consequences and MSolutions
dEF ChkIn addition, the yellowåDEF indicator lamp lights up in the instru-
ment cluster and a warning tone sounds.
The DEF supply has dropped below 1.5 US gal (5.5 l).
XAdd DEF supply (Ypage 128). The
The å DEF indicator lamp only disappears when the vehicle is
stationary, at the latest after 20 secondsa s soon as you switch on
the ignition or start the engine after refueling.
In addition, the yellow ;Check Engine indicator lamp and the yel-
low å DEF indicator lamp light up in the instrument cluster and a
warning tone sounds.
The DEF reducing agent is contaminated, diluted or is not compliant
with ISO 22241.
XHave the DEF tank cleaned and refilled at a qualified specialist
workshop as soon as possible.
StArtS RExxIn addition, the yellow åDEF indicator lamp lights up and a warning
tone sequence sounds.
The DEF supply has dropped below the 0.8 US gal (3.0 l) reserve mark.
After the message appears for the first time, the remaining DEF supply
will last for approximately 1200 miles (1900 km). The engine can then
only be started another 16 times.
The number of remaining engine starts XX
(16to1) is shown in the
message every time the engine is started.
XAdd at least 1.5 US gal (5.5 l) of DEF (Ypage 128).
The å DEF indicator lamp only disappears when the vehicle is
stationary, at the latest after 20 seconds as soon as you switch on the ignition or start the engine after refueling.
178Display messages
On-board computer and displays

Display messagesPossible causes/consequences andMSolutions
å
IdleMod e
The yellow ;enginediagnostic indicator lamp also lights up and
three short warning tone ssound.
You canno tdrive th evehicl eat aspeed exceedin g 5mph (8 km/h).
XAddat least 1. 5US gal (5.5l)of DEF (Ypage 128).
The display message and the yellow ;engine diagnostic indi-
cator lamp only disappear when the vehicle is stationary, at the
latest after 20 seconds as soon as you switch on the ignition or start
the engine after topping up.
Check DieselExhaust Fluid seeOperator's Manual
In addition, the yellow ;engine diagnostic indicator lamp lights up
and a warning tone sounds.
The DEF reducing agent is contaminated, diluted or is not compliant
with ISO 22241.
XHave the DEF tank cleaned and refilled at a qualified specialist
workshop as soon as possible.
å
XX starts remaining
The yellow ;engine diagnostic indicator lamp also lights up and
three short warning tones sound.
After the message appears for the first time, the remaining DEF supply
will last for approximately 1200 miles (1900 km). The engine can then
only be started another 16 times.
The number of remaining engine starts xx
(16to0) is shown in the
message every time the engine is started.
The DEF reducing agent is contaminated, diluted or is not compliant
with ISO 22241.
The exhaust gas aftertreatment is malfunctioning or an emission rel-
evant malfunction has occurred. This malfunction or defect can dam-
age the exhaust gas aftertreatment.
XVisit a qualified specialist workshop immediately.
å
Idle Mode
The yellow ;engine diagnostic indicator lamp also lights up and
three short warning tones sound.
You cannot drive the vehicle at a speed exceeding 5 mph (8 km/h).
XVisit a qualified specialist workshop immediately.
Display messages189
On-board computer and displays
Z