Page 442 of 585

441 Practical hints
What to do if …
Display message
Possible
cause/conse-
quence
Possible solutionMonitor the 59indicator lamp on the center console (
page 89) and
the multifunction display in the instrument cluster (
page 26) for the following:
With the seat unoccupied and the ignition turned on,
the 59indicator lamp on the center console should illuminate and
remain illuminated, indicating that the OCS (
page 85) has deactivated the air
bag.
the message
Front passenger airbag enabled See Operator’s Manual
or the
message
Front passenger airbag disabled See Operator’s Manual
should not
appear in the multifunction display at any time the seat is unoccupied. Wait at last
60 seconds for the system to complete the necessary check cycles and to make
sure neither message appears in the multifunction display.
If above conditions are met, you can occupy the front passenger seat again.
Depending on the front passenger classification sensed by the OCS (
page 85),
the59indicator lamp will remain illuminated or go out.
If above conditions are not met, the system is not working properly. Have the system
checked as soon as possible by an authorized Mercedes-Benz Light Truck Center.
Warning!
G
If the 59indicator lamp
remains out even after performing the above
corrective steps, do not have any children
12 years old and under and other small
individuals use the front passenger seat
until the system has been repaired.
Page 444 of 585

443 Practical hints
What to do if …
Display message
Possible
cause/conse-
quence
Possible solutionMonitor the 59indicator lamp on the center console (
page 89) and
the multifunction display in the instrument cluster (
page 26) for the following:
With the seat unoccupied and the ignition turned on,
the 59indicator lamp on the center console should illuminate and
remain illuminated, indicating that the OCS (
page 85) has deactivated the air
bag.
the message
Front passenger airbag enabled See Operator’s Manual
or the
message
Front passenger airbag disabled See Operator’s Manual
should not
appear in the multifunction display at any time the seat is unoccupied. Wait at last
60 seconds for the system to complete the necessary check cycles and to make
sure neither message appears in the multifunction display.
If above conditions are met, you can occupy the front passenger seat again.
Depending on the front passenger classification sensed by the OCS (
page 85),
the59indicator lamp will remain illuminated or go out.
If above conditions are not met, the system is not working properly. Have the system
checked as soon as possible by an authorized Mercedes-Benz Light Truck Center.
Warning!
G
If the 59indicator lamp
remains illuminated with an adult occupant
on the front passenger seat even after per-
forming the above corrective steps, do not
have any passenger use the front passenger
seat until the system has been repaired.
Page 445 of 585

444 Practical hintsWhat to do if …Display message
Possible cause/consequence
Possible solution
Check tires
Then restart
Run Flat Indicator
There was a warning message about
a loss in the tire inflation pressure
and the Run Flat Indicator has not
been reactivated yet.
Make sure that the correct tire inflation pressure is set
for each tire.
Then reactivate the Run Flat Indicator (
page 378).
Run Flat Indicator
inoperative
The Run Flat Indicator is malfunction-
ing.
Have the Run Flat Indicator checked by an authorized
Mercedes-Benz Light Truck Center.
Tire pressure
Check tires
The Run Flat Indicator indicates that
the pressure is too low in one or more
tires.
Carefully bring the vehicle to a halt, avoiding abrupt
steering and braking maneuvers. Observe the traffic sit-
uation around you.
Check and adjust tire inflation pressure as required
(page 375).
If necessary, replace the wheel (
page 497).
Reactivate the Run Flat Indicator after adjusting the tire
inflation pressure values (
page 378).
Tire pressure
displayed after
driving for
a few minutes
Vehicles with Advanced TPMS*:
The tire inflation pressure is being
checked.
Drive the vehicle for a few minutes.
Page 450 of 585

449 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
;
(USA only)
3
(Canada only)
Check
brake fluid level
There is insufficient brake fluid
in the reservoir.
Risk of accident! Stop the vehicle in a
safe location or as soon at is safe to do
so.
Apply the parking brake (
page 65).
Notify an authorized Mercedes-Benz
Light Truck Center. Do not add brake
fluid! This will not solve the problem.
?
(USA only)
±
(Canada only)
Engine
Service
There may be a malfunction in
the
fuel injection system
ignition system
exhaust system
fuel system
Have the engine checked by an
authorized Mercedes-Benz Light Truck
Center.
Warning!
G
Driving with the message
Check brake
fluid level
displayed can result in an ac-
cident. Have your brake system checked im-
mediately. Do not add brake fluid before
checking the brake system. Overfilling the
brake fluid reservoir can result in spilling
brake fluid on hot engine parts and the
brake fluid catching fire. You could be seri-
ously burned.
!
If you find that the brake fluid in the brake
fluid reservoir has fallen to the minimum mark or
below, have the brake system checked for brake
pad thickness and leaks.
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.