MERCEDES-BENZ R500 2006 W251 Owner's Manual

430 Practical hintsWhat to do if …Display symbol
Display message
Possible cause/consequence
Possible solution
#
Undervoltage
Switch off consumers
The battery has insufficient
voltage.

Turn off unnecessary electrical
consumers.
Battery/Alternator
Stop vehicle
The battery is defective.

Stop the vehicle in a safe location or as
soon as it is safe to do so.

Do not continue to drive.

Notify an authorized Mercedes-Benz
Light Truck Center.
2
Brake wear
Visit workshop
The brake pads have reached
their wear limit.

Have the brake pads replaced as soon as
possible.
!Brake pad thickness must be visually
inspected by a qualified technician at
the intervals specified in the
Maintenance Booklet.

431 Practical hints
What to do if …
Display symbol
Display message
Possible cause/consequence
Possible solution
;
(USA only)
!
(Canada only)
Release
parking brake
You are driving with the parking
brake set.

Release the parking brake (
page 56).
;
(USA only)
3
(Canada only)
Changed braking behavior
Drive with extreme care
A malfunction in the Electronic
Brake Proportioning
(page 102) was detected.

Continue driving with added caution.
Wheels may lock during hard braking,
reducing steering capability.

Read and observe messages in the multi-
function display.

Have the system checked at an autho-
rized Mercedes-Benz Light Truck Center
as soon as possible.
Failure to follow these instructions increases
the risk of an accident.

432 Practical hintsWhat to do if …Display symbol
Display message
Possible cause/consequence
Possible solution
;
(USA only)
3
(Canada only)
Brake fluid too low
Visit workshop
There is insufficient brake fluid
in the reservoir.

Risk of accident! Stop the vehicle in a
safe location or as soon as it is safe to do
so and notify 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.

433 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
?
(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 autho-
rized Mercedes-Benz Light Truck Center.
B
Coolant
Check level
The coolant level is too low.

Add coolant (
page 351).

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
engine damage.

434 Practical hintsWhat 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
Ï
Coolant
Stop, engine off
The coolant is too hot.

Stop the vehicle in a safe location or as
soon as it is safe to do so and immediate-
ly turn off the engine.

Only start the engine again after the
message disappears. You could
otherwise damage the engine.
Warning!
G
Driving when your engine is badly overheat-
ed 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 and can occur just by opening
the engine hood. Stay away from the engine
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.

435 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
Ï
Coolant
Stop, engine off
The poly-V-belt could be broken.

Stop the vehicle in a safe location or as soon
as it is safe to do so 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 wa-
ter 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 Limited Warranty.

Observe the coolant temperature in the
multifunction display (
page 168).

Drive immediately to the nearest authorized
Mercedes-Benz Light Truck Center.

436 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause/consequence
Possible solution
Ï
Coolant
Visit workshop
The cooling fan for the coolant is
malfunctioning.

Observe the coolant temperature in the
multifunction display (
page 168).

Have the fan replaced as soon as possi-
ble.
G
Display malfunction
Visit workshop
The instrument cluster display is
malfunctioning.

Continue driving with added caution.

Visit an authorized Mercedes-Benz Light
Truck Center as soon as possible.
The displays for several systems
have malfunctioned. Some sys-
tems themselves may also have
malfunctioned.

Have the electronic systems checked by
an authorized Mercedes-Benz Light Truck
Center.
±
Display malfunction
Visit workshop
Certain electronic systems are
unable to relay information to
the control system. The follow-
ing systems may have failed:

Coolant temperature display


Tachometer


Cruise control display

Have the electronic systems checked by
an authorized Mercedes-Benz Light Truck
Center.
c

Door open
You are attempting to drive with
one or more doors open.

Close the doors.

437 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
N
Check eng. oil level
when next refueling
The engine oil level is too low.

Check the engine oil level (
page 346).
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 349) and check
the engine oil level (page 346).
Engine oil level
Stop, 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 as it is safe to do so in a safe
location.

Turn off the engine.

Add engine oil (
page 349) and check
the engine oil level (page 346).
Engine oil level
Reduce oil level
You have added too much
engine oil. There is a risk of dam-
aging the engine or the catalytic
converter.

Have oil siphoned or drained off.
Observe all legal requirements with
respect to its disposal.
Change engine oil
Visit workshop
It may be that there is water in
the engine oil.

Have the engine oil checked.

438 Practical hintsWhat to do if …When the message
Add 1 qt. engine oil
when 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
Engine oil level
Visit workshop
The engine oil has dropped to a
critical level.

Check the engine oil level (
page 346)
and add oil as required (
page 349).

If you must add engine oil frequently, have
the engine checked for possible leaks.
Oil sensor malfunction
Visit workshop
The measuring system is
malfunctioning.

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.

439 Practical hints
What to do if …
Display symbol
Display messages
Possible cause/consequence
Possible solution
A
Check gas cap
See Operator’s Manual
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 342).
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
Hood open
Trunk open
You are driving with the hood or
the tailgate open.

Close the hood (
page 345) or the
tailgate (
page 124).
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 124).