Page 451 of 585
450 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
Ï
Coolant level
Stop car, switch engine off
The coolant is too hot.
Among other possible causes
(the cooling fan could be
malfunctioning), the poly-V-belt
could be broken.
Stop the vehicle in safe location or as
soon as it safe to do so.
Apply the parking brake (
page 65).
Turn off the engine.
Check the poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise, the
engine will overheat due to an inoperative
water pump which may result in damage
to the engine. Contact an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Do not continue to drive the vehicle with
this message displayed. Doing so could
result in serious engine damage that is
not covered by the Mercedes-Benz Limit-
ed Warranty.
(Continued on next page)
Page 452 of 585

451 Practical hints
What to do if …
During severe operation conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbol
Display messages
Possible cause/consequence
Possible solution
Observe the coolant temperature in the
multifunction display (
page 154).
If the temperature raises again:
Contact an authorized Mercedes-Benz
Light Truck Center immediately.
Warning!
G
Driving when your engine is overheated can
cause some fluids which may have leaked
into the engine compartment to catch fire.
You could be seriously burned.
Steam from an overheated engine can cause
serious burns which can occur just by open-
ing the engine hood. Stay away from the en-
gine if you see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.
!
The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious damage which is not
covered by the Mercedes-Benz Limited
Warranty.
Page 453 of 585

452 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
B
Top up Coolant
See Oper. Manual
The coolant level is too low.
Add coolant (
page 362).
If you have to add coolant frequently,
have the cooling system checked by an
authorized Mercedes-Benz Light Truck
Center.
Warning!
G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You could be seriously burned.Warning!
G
In order to avoid potentially serious burns:
Use extreme caution when opening the
hood if there are any signs of steam or
coolant leaking from the cooling system,
or if the coolant temperature gauge indi-
cates that the coolant is overheated.
Do not remove pressure cap on coolant
reservoir if coolant temperature is
above 158°F (70°C). Allow engine to
cool down before removing cap. The
coolant reservoir contains hot fluid and
is under pressure.
Using a rag, slowly open the cap approx-
imately
1/2 turn to relieve excess pres-
sure. If opened immediately, scalding
hot fluid and steam will be blown out un-
der pressure.
Do not spill antifreeze on hot engine
parts. Antifreeze contains ethylene gly-
col which may burn if it comes into con-
tact with hot engine parts.
!
Do not ignore the low engine coolant level
warning. Extended driving with the message and
symbol displayed may cause serious engine
damage not covered by the Mercedes-Benz
Limited Warranty.
Do not drive without sufficient amount of coolant
in the cooling system. The engine will overheat
causing major engine damage.
Page 454 of 585

453 Practical hints
What to do if …
When the message
Add 1 qt. engine oil
at next refueling (Canada:
1 liter
)
appears while the engine is running and at
operating temperature, the engine oil level
has dropped to approximately the mini-
mum level.
When this occurs, the warning will first
come on intermittently and then stay on if
the oil level drops further.Visually check for oil leaks. If no obvious oil
leaks are noted, drive to the nearest
service station where the engine oil should
be topped to the required level with an ap-
proved oil specified in the Factory
Approved Service Products pamphlet.
Display symbol
Display messages
Possible cause/consequence
Possible solution
N
Check eng. oil level
at next refueling
The engine oil level is too low.
Check the engine oil level (
page 360)
(except ML 500), or (
page 358)
(ML 500 only).
USA only:Add 1 qt. engine oil
at next refuelingCanada only:Add 1 liter engine oil
at next refueling
The engine oil level is too low.
Add engine oil (
page 361) and check
the engine oil level (page 360) (except
ML 500), or (
page 358) (ML 500 only).
Engine oil level
cannot be measured
The measuring system is
malfunctioning.
Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.
Page 455 of 585

454 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/conse-
quence
Possible solution
N
Engine oil level
Stop car, turn engine off
There is no oil in the engine.
There is a danger of engine
damage.
Carefully bring the vehicle to a halt as soon as
it is safe to do so in a safe location.
Turn off the engine.
Add engine oil (
page 361) and check the en-
gine oil level (
page 360) (except ML 500), or
(
page 358) (ML 500 only).
Engine oil level
Reduce oil level
You have added too much
engine oil. There is a risk of
damaging the engine and/or
the catalytic converter (gaso-
line engine) or the oxidation
catalyst (diesel engine).
Have oil siphoned or drained off.
Observe all legal requirements with respect to
its disposal.
Engine oil level
Visit workshop
The engine oil has dropped to
a critical level.
Check the engine oil level (
page 360) (except
ML 500), or (
page 358) (ML 500 only) and
add oil as required (
page 361).
If you must add engine oil frequently, have the
engine checked for possible leaks.
!
The engine oil level warnings should not be
ignored. Extended driving with the symbol dis-
played could result in serious engine damagethat is not covered by the Mercedes-Benz
Limited Warranty.
Page 456 of 585
455 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
c
You are driving with one or more
doors open.
Stop the vehicle in a safe location or as
soon as it is safe to do so.
Close the door(s).
A
Gas cap is open
A loss of pressure has been
detected in the fuel system. The
fuel cap may not be closed
properly or the fuel system may
be leaky.
Check the fuel cap (
page 352).
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked by an
authorized Mercedes-Benz Light Truck
Center.
a
You are driving with the hood or
the tailgate open.
Carefully bring the vehicle to a halt as
soon as it is safe to do so in a safe
location.
Close the hood (
page 356) or the
tailgate (
page 121).
You are trying to lock the vehicle
with the KEYLESS-GO* function
with a door or the tailgate open.
Close all doors and/or the tailgate
(page 121).
Page 457 of 585

456 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
F
Key
not detected
The SmartKey with
KEYLESS-GO* is not recognized
while the engine is running
because
the SmartKey with
KEYLESS-GO* is not in the
vehicle
there is strong
radio-frequency interference
Stop the vehicle in a safe location or as
soon as it is safe to do so.
Apply the parking brake (
page 65).
Search for the SmartKey with
KEYLESS-GO*.
Otherwise the vehicle cannot be centrally
locked nor can the engine be started
again after the engine is stopped.
The SmartKey with
KEYLESS-GO* is momentarily
not recognized.
Change the position of the SmartKey with
KEYLESS-GO* in the vehicle.
Operate the vehicle with the SmartKey in
the starter switch if necessary.
Key
not detected
The SmartKey with
KEYLESS-GO* is not recognized
while the ignition is switched on
(page 40) and a door is
opened or closed and the
SmartKey with KEYLESS-GO* is
not in the vehicle.
Search for the SmartKey with
KEYLESS-GO*.
Otherwise the vehicle cannot be locked
nor can the engine be started.
Change the position of the SmartKey with
KEYLESS-GO* in the vehicle.
Page 458 of 585

457 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
F
Key detected
in vehicle
A SmartKey with KEYLESS-GO*
left in the vehicle was detected
while trying to lock the vehicle
from the outside.
Take the SmartKey with KEYLESS-GO*
out of the vehicle.
Remove key
You have forgotten to remove
the SmartKey.
Remove the SmartKey from the starter
switch.
You need a new key
There is no additional code avail-
able for SmartKey or SmartKey
with KEYLESS-GO*.
Visit an authorized Mercedes-Benz Light
Truck Center as soon as possible.
Change
key batteries
The batteries in the SmartKey
with KEYLESS-GO* are dis-
charged.
Replace the batteries (
page 480).
Don’t forget
your key
This message appears for a
maximum of 60 seconds if the
driver’s door is opened with the
engine shut off and no SmartKey
in the starter switch.
This message is only a reminder.
Insert the SmartKey in the starter switch
(page 40).
or
Take the SmartKey with KEYLESS-GO*
with you when leaving the vehicle.