MERCEDES-BENZ R350 2008 W251 Owner's Manual

450 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
B Top Up Coolant
See Operator’s ManualThe coolant level is too low.Add coolant (page 360).
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.
!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.

451 Practical hints
What to do if …
When the message Check engine oil
level at next refueling.
appears while
the engine is running and at operating tem-
perature, 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
approved engine oil.
For information on approved engine oils,
refer to the Factory Approved Service
Products pamphlet (USA only) or contact
an authorized Mercedes-Benz Light Truck
Center.
Display symbolDisplay messagePossible cause/consequencePossible solution
NCheck engine oil level
at next refueling.The engine oil level is too low.Check the engine oil level (page 358).
!The engine oil level warning 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.

452 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible 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 doors.
]Clean
Fuel FilterContact an authorized Mercedes-Benz
Light Truck Center.
A Gas Cap OpenA 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.
aYou 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 119).
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 119).

453 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
FKey
Not DetectedThe SmartKey with
KEYLESS-GO* is not detected
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 detected.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 DetectedThe SmartKey with
KEYLESS-GO* is not detected
while the ignition is switched on
(
page 39) 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.

454 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
FKey Detected
In VehicleA 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 KeyYou 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*.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Key
Does Not Belong to VehicleThe SmartKey or SmartKey with
KEYLESS-GO* in the starter
switch does not belong to the
vehicle.Find the SmartKey or SmartKey with
KEYLESS-GO* that belongs to the vehicle
to operate the vehicle.
Change
Key BatteriesThe batteries in the SmartKey
with KEYLESS-GO* are dis-
charged.Replace the batteries (page 479).
Don’t Forget
Your KeyThis 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 SmartKey in the starter switch.
or
Take the SmartKey with KEYLESS-GO*
with you when leaving the vehicle.

455 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
.3rd Brake LampThe high mounted brake lamp is
malfunctioning. This message
will only appear if a critical
number of LEDs have stopped
working.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Active Headlamps
InoperativeThe active Bi-Xenon* headlamp
system is malfunctioning.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
AUTO Light
InoperativeThe light sensor is malfunction-
ing. The headlamps switch on
automatically.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
To switch off the headlamps
(U.S. vehicles only):
In the control system, set lamp operation
to manual mode (
page 144).
Switch off the headlamps using the
exterior lamp switch (
page 143).
Brake Lamp
LeftThe left brake lamp is malfunc-
tioning. A substitute bulb is
being used.Replace the bulb as soon as possible
(
page 480).
Brake Lamp
RightThe right brake lamp is malfunc-
tioning. A substitute bulb is
being used.Replace the bulb as soon as possible
(
page 480).

456 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
.Cornering Lamp
LeftThe left corner-illuminating front
fog lamp is malfunctioning.Replace the bulb as soon as possible
(
page 480).
Cornering Lamp
RightThe right corner-illuminating
front fog lamp is malfunctioning.Replace the bulb as soon as possible
(
page 480).
Front Foglamp
LeftThe left front fog lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 480).
Front Foglamp
RightThe right front fog lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 480).
High Beam
LeftThe left high beam lamp is
malfunctioning.Halogen headlamp:
Replace the bulb as soon as possible
(
page 480).
Bi-Xenon* headlamp:
Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
High Beam
RightThe right high beam lamp is
malfunctioning.Halogen headlamp:
Replace the bulb as soon as possible
(
page 480).
Bi-Xenon* headlamp:
Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.

457 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
.License Plate Lamp
LeftThe left license plate lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 480).
License Plate Lamp
RightThe right license plate lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 480).
Low Beam
LeftThe left low beam lamp is
malfunctioning.Halogen headlamp:
Replace the bulb as soon as possible
(
page 480).
Bi-Xenon* headlamp:
Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Low Beam
RightThe right low beam lamp is
malfunctioning.Halogen headlamp:
Replace the bulb as soon as possible
(
page 480).
Bi-Xenon* headlamp:
Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.

458 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
.Marker Lamp
Front LeftThe left front side marker lamp is
malfunctioning.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Marker Lamp
Front RightThe right front side marker lamp
is malfunctioning.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Parking Lamp
Front LeftThe front left parking lamp is
malfunctioning. A substitute
bulb is being used.Replace the bulb as soon as possible
(
page 480).
Parking Lamp
Front RightThe front right parking lamp is
malfunctioning. A substitute
bulb is being used.Replace the bulb as soon as possible
(
page 480).
Foglamp
Rear LeftThe left rear fog lamp is malfunc-
tioning.Replace the bulb as soon as possible
(
page 480).
Reverse Lamp
LeftThe left backup lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 480).
Reverse Lamp
RightThe right backup lamp is
malfunctioning.Replace the bulb as soon as possible
(
page 480).

459 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
. Switch Off LightsYou have removed the SmartKey
from the starter switch and
opened the driver’s door or
removed the SmartKey with
KEYLESS-GO* from the vehicle
and left the parking lamps or the
rear fog lamp on.Turn the exterior lamp switch toM
(
page 143).
Tail Lamp
LeftThe left tail lamp is malfunction-
ing. A substitute bulb is being
used.Replace the bulb as soon as possible
(
page 480).
Tail Lamp
RightThe right tail lamp is malfunc-
tioning. A substitute bulb is
being used.Replace the bulb as soon as possible
(
page 480).