Page 362 of 473

361 Practical hints
What to do if …
Display message Possible cause/consequencePossible solution
Front passenger
airbag enabled
See Operator’s
ManualThe passenger front air bag and the
passenger-side knee bag are
activated while driving even though a
child, small individual, or object below
the system’s weight threshold is on
the passenger seat, or the passenger
seat is empty. Objects on the seat or
forces acting on the seat may make
the system sense supplemental
weight.Stop the vehicle in a safe location as soon as possible and check the
passenger seat for the following:
Switch off the ignition (page 37).
Apply the parking brake (page 59).
Remove child and child restraint from passenger seat.
Make sure that no objects which are applying supplemental weight
onto the seat are present. The system may recognize such supple-
mental weight and sense that an occupant on the passenger seat is
of a greater weight than actually present.
Keep the seat unoccupied, close the passenger door and switch on
the ignition (
page 37).
Monitor the 75indicator lamp on the center console
(
page 29) and the multifunction display in the instrument cluster
(
page 121) for the following:
(Continued on next page)
Page 364 of 473
363 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Front passenger
airbag disabled
See Operator’s
ManualThe passenger front air bag and the
passenger-side knee bag are
deactivated while driving even though
an adult or someone larger than a
small individual is occupying the front
passenger seat. Forces acting on the
seat may make the system sense a
decrease in weight.Stop the vehicle in a safe location as soon as possible and check the
passenger seat for the following:
Switch off the ignition (page 37).
Apply the parking brake (page 59).
Have the passenger vacate the seat and exit the vehicle.
Keep the seat unoccupied, close the passenger door and switch on
the ignition (
page 37).
Monitor the 75indicator lamp on the center console
(
page 29) and the multifunction display in the instrument cluster
(
page 121) for the following:
(Continued on next page)
Page 366 of 473

365 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Run Flat
IndicatorinoperativeThe Run Flat Indicator* is malfunc-
tioning.Have the Run Flat Indicator* checked by an
authorized Mercedes-Benz Center.
The Run Flat Indicator* has been
switched off due to a malfunction.
Tire pressureCheck tiresThe Run Flat Indicator* indicates
that the pressure is too low in one or
more tires.Carefully bring the vehicle to a halt, avoiding
abrupt steering and braking maneuvers. Observe
the traffic situation around you.
Check and adjust the tire inflation pressure as
required (
page 314).
If necessary, change the wheel (page 401).
Restart the Run Flat Indicator* after adjusting the
tire inflation pressure values (
page 314).
Check tiresThen restart
Run Flat IndicatorThere was a warning message about
a loss in tire inflation pressure and
the Run Flat Indicator* has not been
restarted yet.Make sure that the correct tire inflation pressure
is set for each tire.
Then restart the Run Flat Indicator*
(
page 316).
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle.
You may lose control of the vehicle. Contin-
ued driving with a flat tire will cause exces-
sive heat build-up and possibly a fire.
Page 367 of 473
366 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
#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 the vehicle immediately in a safe loca-
tion 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. Contact
an authorized Mercedes-Benz Center.
If it is in order:
Contact an Mercedes-Benz Center
immediately. Adjust driving to be consis-
tent with reduced braking responsive-
ness.
USA only:
;
Canada only:
!
Release
parking brakeYou are driving with the parking
brake set.Release the parking brake (page 53).
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367 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
USA only:
;
Canada only:
3
Check
brake fluid levelThere 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.
Turn off the engine.
Apply the parking brake (page 59).
Do not drive any further.
Contact an authorized Mercedes-Benz Center.
Do not add brake fluid! This will not solve the
problem.
2Brake wearThe brake pads have reached their
wear limit.Have the brake pads replaced as soon as
possible.
Warning!G
Driving with the message Check brake
fluid level
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
checked by a qualified technician at the intervals
specified in the Maintenance Booklet.
Page 369 of 473
368 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
•Coolant
Stop, turn engine
offThe coolant is too hot.
Among other possible causes,
the poly-V-belt could be broken.Stop the vehicle in a safe location or as soon as it is
safe to do so.
Turn off the engine.
Apply the parking brake (page 59).
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. Contact an
authorized Mercedes-Benz Center.
If it is intact:
Wait for the message to disappear before restarting
the engine.
Doing otherwise could result in serious engine
damage that is not covered by the Mercedes-Benz
Limited Warranty.
(Continued on next page)
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373 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
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 Center.
Display symbolDisplay messagePossible cause/consequencePossible solution
NEngine oil level
Reduce oil levelSLK 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 level
Stop, turn engine offThere is no oil in the engine. There
is a danger of engine damage.Stop the vehicle in a safe location or as soon
as it is safe to do so.
Turn off the engine.
Apply the parking brake (page 59).
Add engine oil (page 299) and check the
engine oil level (
page 296).
!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.
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375 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
OYou are driving with the hood open.Risk of accident!
Stop the vehicle in a safe location or as soon
as it is safe to do so.
Apply the parking brake (page 59).
Close the hood (page 294).
IPlease
get a new keyThe SmartKey is malfunctioning.Contact an authorized Mercedes-Benz
Center.
Remove keyYou have forgotten to remove the
SmartKey from the starter switch.Remove the SmartKey from the starter
switch.
.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
Center as soon as possible.
AUTO-Light
inoperativeThe light sensor is malfunctioning.
The headlamps switch on automati-
cally.Contact an authorized Mercedes-Benz
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 143).
Switch off headlamps using the exterior
lamp switch (
page 109).