Page 377 of 481

376 Practical hintsWhat to do if …During severe operating conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).Display symbol
Display message
Possible cause/conse-
quence
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 (
page 437).
If it is broken:
Do not continue to drive. Otherwise the engine will overheat
due to an inoperative water pump which may result in dam-
age to the engine. Notify an authorized Mercedes-Benz
Center.
If it is in order:
Do not continue to drive the vehicle with this message dis-
played. Doing so could result in serious engine damage that
is not covered by the Mercedes-Benz Limited Warranty.
Drive immediately to the nearest authorized
Mercedes-Benz Center.
Observe the coolant temperature display (
page 128).
!The engine should not be operated with
the coolant temperature above 248°F
(120°C).
Doing so may cause serious engine
damage which is not covered by the
Mercedes-Benz Limited Warranty.
Page 378 of 481

377 Practical hints
What to do if …
Display symbol
Display message
Possible cause/consequence
Possible solution
Ï
Coolant
Stop, engine off
The coolant is too hot.
Stop the vehicle and turn off the engine.
Only start the engine again after the mes-
sage disappears. You could otherwise dam-
age the engine.
/
Coolant
Check level
The coolant level is too low.
Add coolant (
page 313).
If you have to add coolant frequently, have
the cooling system checked by an autho-
rized Mercedes-Benz Center.
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 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 engine damage
which is not covered by the Mercedes-Benz
Limited Warranty.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
this 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 379 of 481

378 Practical hintsWhat to do if …Display symbol
Display message
Possible cause/consequence
Possible solution
±
Display malfunction
Visit workshop
Certain electronic systems are un-
able to relay information to the con-
trol system. The following systems
may have failed:
Coolant temperature display
Tachometer
Cruise control display
Have the electronic systems checked by an
authorized Mercedes-Benz Center.
G
Display malfunction
Visit workshop
The instrument cluster display is
malfunctioning.
When the display is malfunctioning, warnings
and malfunction messages might not be dis-
played.
Continue driving with added caution.
Visit an authorized Mercedes-Benz Center
as soon as possible.
The displays for several systems
have malfunctioned. Some systems
themselves may also have malfunc-
tioned.
Continue driving with added caution.
Have the electronic systems checked by an
authorized Mercedes-Benz Center.
J
Doors open
You are attempting to drive with
one or more doors open.
Close all doors.
Page 380 of 481

379 Practical hints
What to do if …
When the message
Add 1 qt.
(Canada:
1 liter
) engine oil when next
refueling (SLK 55 AMG) or
Check oil
level when next refueling (SLK 280,
SLK 350) appears while the engine is run-
ning and at operating temperature, the en-
gine 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 ser-
vice 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 message
Possible cause/consequence
Possible solution
N
Check oil level
when next refueling
SLK 280 and SLK 350 only:
The engine oil level has dropped to
a critical level.
Check the engine oil level (
page 308) and
add engine oil as required (page 312).
If you must add engine oil frequently, have
the engine checked for possible leaks.
USA only:Add 1 qt. engine oil
when next refuelingCanada only:Add 1 liter engine oil
when next refueling
SLK 55 AMG only:
The engine oil level is too low.
Add engine oil (
page 312) and check the
engine oil level (page 308).
!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 381 of 481
380 Practical hintsWhat to do if …Display symbol
Display message
Possible cause/consequence
Possible solution
N
Engine oil level
Stop, engine off
SLK 55 AMG only:
There is no oil in the engine. There
is a danger of engine damage.
Carefully bring the vehicle to a halt as soon
as possible.
Turn off the engine.
Add engine oil (
page 312) and check the
engine oil level (page 308).
Engine oil level
Visit workshop
SLK 55 AMG only:
The measuring system is malfunc-
tioning.
Have the measuring system checked by an
authorized Mercedes-Benz Center.
Engine oil level
Reduce oil level
SLK 55 AMG only:
You have added too much engine
oil. There is a risk of damaging the
engine or the catalytic converter.
Have oil siphoned or drained off.
Observe all legal requirements with respect
to its disposal.
Engine oil
Visit workshop
SLK 55 AMG only:
There may be water in the engine
oil.
Have the engine oil checked.
Page 382 of 481

381 Practical hints
What to do if …
Display symbol
Display message
Possible cause/consequence
Possible solution
A
Fuel reserve
The fuel level has dropped below
the reserve mark.
Refuel at the next gas station (
page 304).
Check gas cap
See Operator’s Manual
The fuel cap may not be closed
properly.
Check the fuel cap (
page 304).
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked by an autho-
rized Mercedes-Benz Center.
K
Lock retractable roof
You are driving with the retractable
hardtop not properly locked.
Stop the vehicle in a safe location. Observe
the traffic situation around you.
Push the retractable hardtop switch forward
or rearward until the retractable hardtop is
completely closed or open (
page 252).
Retractable roof
Visit workshop
The retractable hardtop is
malfunctioning.
Have the retractable hardtop checked by an
authorized Mercedes-Benz Center.
O
Close hood!
You are driving with the hood open.
Close the hood (
page 307).
F
Replace key
The SmartKey is malfunctioning.
Visit an authorized Mercedes-Benz Center.
Page 383 of 481

382 Practical hintsWhat to do if …Display symbol
Display message
Possible cause/consequence
Possible solution
.
3rd brake light
The high mounted brake lamp is
malfunctioning. This message will
only appear if a critical number of
LEDs have stopped working.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Tail lamp / brake lamp
left
Back-up lamp on
The left tail lamp/brake lamp is
malfunctioning. This message will
only appear if a critical number of
LEDs have stopped working.
A backup bulb has been brought
into use.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Tail lamp / brake lamp
right
Back-up lamp on
The right tail lamp/brake lamp is
malfunctioning. This message will
only appear if a critical number of
LEDs have stopped working.
A backup bulb has been brought
into use.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Brake lamp
Visit workshop
Brake lamp illumination is delayed
or lamp is permanently on.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Front foglamp, L
The left front fog lamp is malfunc-
tioning.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Front foglamp, R
The right front foglamp is malfunc-
tioning.
Visit an authorized Mercedes-Benz Center
as soon as possible.
Page 384 of 481

383 Practical hints
What to do if …
.
Rear foglamp
Back-up lamp on
The rear fog lamp on the driver’s
side is malfunctioning. A backup
bulb has been brought into use.
Replace the bulb as soon as possible.
High beam, left
The left high beam lamp (halogen
headlamps)/high beam flasher
lamp (Bi-Xenon* headlamps) is mal-
functioning.
Replace the bulb as soon as possible.
High beam, right
The right high beam lamp (halogen
headlamps)/high beam flasher
lamp (Bi-Xenon* headlamps) is mal-
functioning.
Replace the bulb as soon as possible.
Lamp sensor
Drive to workshop
The light sensor is malfunctioning.
The headlamps switch on automati-
cally.
In the control system, set lamp operation to
manual (
page 143).
Switch on headlamps using the exterior
lamp switch (
page 110).
Visit an authorized Mercedes-Benz Center
as soon as possible.
Left license plate
lamp malfunction
The left license plate lamp is mal-
functioning.
Replace the bulb as soon as possible.
Right license plate
lamp malfunction
The right license plate lamp is mal-
functioning.
Replace the bulb as soon as possible.
Display symbol
Display message
Possible cause/consequence
Possible solution