Page 408 of 539
407 Practical hints
What to do if …
Symbol messagesDisplay symbol
Display messages
Possible cause
Possible solution
#
Undervoltage
Switch off consumers
The battery has insufficient volt-
age.
Turn off unnecessary electrical
consumers.
malfunction
Visit workshop
The battery was charged with a
battery charger or jump started.
Have the battery checked at a service
station.
Battery/Alternator
Stop vehicle
The battery is no longer charg-
ing.
Possible causes:
alternator malfunctioning
broken poly-V-belt
Do not forget that the brake sys-
tem requires electrical energy
and may be operating with re-
stricted capability. Considerably
greater brake pedal force is
required and the stopping dis-
tance is increased.
Stop immediately and 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. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Drive immediately to the nearest autho-
rized Mercedes-Benz Light Truck Center.
Adjust driving to be consistent with re-
duced braking responsiveness.
Page 410 of 539
409 Practical hints
What to do if …
Display symbol
Display message
Possible cause
Possible solution
;
(USA only)
!
(Canada only)
Release
parking brake
You are driving with the parking
brake set.
Release the parking brake (
page 52).
Brake fluid too low
Visit workshop
There is insufficient brake fluid
in the reservoir.
Risk of accident! Stop the vehicle and no-
tify an authorized Mercedes-Benz Light
Truck Center. Do not add brake fluid! This
will not solve the problem.
Warning!
G
Driving with the message
Brake fluid
too low Visit workshop
displayed can
result in an accident. Have your brake
system checked immediately. 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 can be seriously 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.
!Brake pad thickness must be visually
inspected by a qualified technician at
the intervals specified in the
Maintenance Booklet.
Page 411 of 539
410 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
?
(USA only)
±
(Canada only)
Visit workshop
There may be a malfunction in
the:
Fuel injection system
Ignition system
Exhaust system
Fuel system
Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.
B
Coolant
Check level
The coolant level is too low.
Add coolant (
page 332).
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 can be seriously burned.
!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 en-
gine damage.
Page 413 of 539
412 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
Ï
Coolant
Stop, engine off
The poly-V-belt could be broken.
Stop the vehicle and immediately 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. Notify 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.
Drive immediately to the nearest autho-
rized Mercedes-Benz Light Truck Center.
Coolant
Visit workshop
The cooling fan for the coolant is
malfunctioning.
Observe the coolant temperature gauge
in the instrument cluster.
Have the fan replaced as soon as possi-
ble.
Page 415 of 539
414 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
N
Check eng. oil level
when next refueling
The engine oil level is too low.
Check the engine oil level (
page 328)
(ML 500 only), or (
page 330) (ML 350
only).
USA only:Add 1 qt. engine oil
when next refuelingCanada only:Add 1 liter engine oil
when next refueling
The engine oil level is too low.
Add engine oil (
page 331) and check
the engine oil level (page 328) (ML 500
only), or (
page 330) (ML 350 only).
Engine oil level
Stop, engine off
There is no oil in the engine.
There is a danger of engine dam-
age.
Carefully bring the vehicle to a halt as
soon as possible.
Turn off the engine.
Add engine oil (
page 331) and check
the engine oil level (page 328) (ML 500
only), or (
page 330) (ML 350 only).
Engine oil level
Reduce oil level
You have added too much en-
gine oil. There is a risk of damag-
ing the engine or the catalytic
converter.
Have oil siphoned or drained off. Observe
all legal requirements with respect to its
disposal.
Page 416 of 539
415 Practical hints
What to do if …
When the
Add 1 qt. engine oil when
next refueling
(Canada:
1 liter
) mes-
sage appears while the engine is running
and at operating temperature, the engine
oil level has dropped to approximately the
minimum 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
Possible solution
N
Engine oil level
Visit workshop
The engine oil has dropped to a
critical level.
Check the engine oil level (
page 328)
(ML 500 only), or (
page 330) (ML 350
only) and add oil as required
(
page 331).
If you must add engine oil frequently, have
the engine checked for possible leaks.
Oil sensor malfunction
Visit workshop
The measuring system is mal-
functioning.
Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.
!The engine oil level warnings should
not be ignored. Extended driving with
the symbol displayed could result in
serious engine damage that is not
covered by the Mercedes-Benz Limited
Warranty.
Page 417 of 539
416 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
A
Reserve fuel
The fuel level has dropped below
the reserve mark.
Refuel at the next gas station
(page 323).
Check gas cap
See Operator’s Manual
A loss of pressure has been de-
tected in the fuel system. The
fuel cap may not be closed prop-
erly or the fuel system may be
leaky.
Check the fuel cap (
page 323).
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked by an au-
thorized Mercedes-Benz Light Truck Cen-
ter.
a
Hood open
Trunk open
You are driving with the hood or
the tailgate open.
Close the hood (
page 326) or the tail-
gate (
page 120).
F
Key
Check battery
The SmartKey with
KEYLESS-GO* batteries are
discharged.
Change the batteries (
page 440).
Please do
not forget key
This display appears (for a maxi-
mum of 60 seconds) if the driv-
er’s door is opened with the
engine shut off and no SmartKey
in the starter switch.
This message is only a reminder.
Insert SmartKey in the starter switch.
Take the SmartKey with KEYLESS-GO*
with you when leaving the vehicle.
Page 464 of 539
463 Practical hints
Battery
!
The battery is a valve-regulated lead
acid (VRLA) battery, also referred to as
“fleece” battery. Such batteries do not
require topping-up of the electrolyte
level. VRLA batteries therefore do not
have cell caps and the battery cover is
non-removable. Do not attempt to
open the battery as otherwise the bat-
tery will be damaged.
Even though VRLA batteries do not
require topping-up of the electrolyte
level and cannot be opened to check
the electrolyte level, the battery condi-
tion must be checked periodically by
performing a battery conductance test.
Refer to Maintenance Booklet for bat-
tery condition testing intervals.
As with any other battery, the battery
may discharge if the vehicle is not
operated for an extended period of
time. You can connect a battery
maintenance charge unit tested and
approved for use on your vehicle model
or disconnect the battery to prevent
battery discharge. Contact an
authorized Mercedes-Benz Light Truck
Center for more information.
!The factory-equipped VRLA battery is
leak-proofed. Only use a battery as re-
placement that has the same security
features and is of identical size,
voltage, and capacity as the
factory-equipped battery.
The battery, the battery ventilation
tube (
page 468) and the vent plug
(
page 468) must always be securely
installed when the vehicle is in opera-
tion.
Warning!
G
Jump starting must only be done using the
jump-start contacts located in the engine
compartment (
page 470).
