Page 355 of 464
355 Practical hints
What to do if …
Symbol messagesDisplay symbol
Display message
Possible cause
Possible solution
#
Battery/Alternator
Visit workshop
The battery is no longer charging.
Possible causes:
Alternator malfunctioning
Broken poly-V-belt
Do not forget that the brake system
requires electrical energy and may
be operating with restricted capa-
bility. Considerably greater brake
pedal force is required and the stop-
ping distance is increased.
Stop immediately and check the poly-V-belt.
If it is broken:
Do not continue to drive. Notify an au-
thorized Mercedes-Benz Center.
If it is in order:
Drive immediately to the nearest autho-
rized Mercedes-Benz Center. Adjust driv-
ing to be consistent with reduced
braking responsiveness.
Page 356 of 464
356 Practical hintsWhat 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 parking brake (
page 49).
2
Brake wear
Visit workshop
The brake pads have reached their
wear limit.
Have the brake pads replaced as soon as
possible.
3
Brake fluid
Visit workshop
There is insufficient brake fluid in
the reservoir.
Risk of accident! Stop the vehicle and notify
an authorized Mercedes-Benz Center. Do
not add brake fluid! This will not solve the
problem.
Warning!
G
Driving with this message displayed can re-
sult in an accident. Have your brake system
checked immediately. Do not add brake flu-
id before checking the brake system.
Overfilling the brake fluid reservoir can re-
sult 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
checked by a qualified technician at the
intervals specified in the Maintenance
Booklet.
Page 357 of 464
357 Practical hints
What 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
Possible solution
Ï
Coolant
Stop, engine off
The poly-V-belt could be
broken.
Stop immediately and check the poly-V-belt (
page 411).
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 122).
!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 358 of 464
358 Practical hintsWhat to do if …Display symbol
Display message
Possible cause
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 293).
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 359 of 464
359 Practical hints
What to do if …
Display symbol
Display message
Possible cause
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 360 of 464
360 Practical hintsWhat 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 350)
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 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
Possible solution
:
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 292) and check the
engine oil level (page 288).
Check oil level
when next refueling
SLK 350 only:
The engine oil level has dropped to
a critical level.
Check the engine oil level (
page 288) and
add engine oil as required (page 292).
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 displayed could result in
serious engine damage that is not
covered by the Mercedes-Benz Limited
Warranty.
Page 361 of 464
361 Practical hints
What to do if …
Display symbol
Display message
Possible cause
Possible solution
:
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 292) and check the
engine oil level (page 288).
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 362 of 464
362 Practical hintsWhat to do if …Display symbol
Display message
Possible cause
Possible solution
A
Fuel reserve
The fuel level has dropped below
the reserve mark.
Refuel at the next gas station (
page 284).
Check gas cap
See Operator’s Manual
The fuel cap may not be closed
properly.
Check the fuel cap (
page 284).
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
The retractable hardtop is not
locked properly.
Push the retractable hardtop switch forward
or rearward until the retractable hardtop is
completely closed or open (
page 237).
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 287).
F
Replace key
The SmartKey is malfunctioning.
Visit an authorized Mercedes-Benz Center.
