Page 351 of 473

350 Practical hints
What to do if …
ProblemPossible cause/consequenceSuggested solution
vThe yellow ESP® warning lamp 
comes on when the engine is 
running.The ESP® has been switched off 
with the ESP® switch or has been 
switched off due to a malfunction.
Risk of accident!
When the ESP
® is switched off, it 
will not stabilize the vehicle if the 
system recognizes that the vehicle 
starts to skid or that a wheel is 
spinning.
The cruise control is deactivated 
and cannot be switched on.
Switch the ESP® back on (page 89).
Exceptions: (
page 86).
If leaving the ESP® switched off, adapt your 
speed and driving to the prevailing road, 
weather and traffic conditions.
If the ESP
® cannot be switched back on:
Continue driving with added caution.
Observe additional messages that may appear 
in the multifunction display (
page 359).
Have the system checked at an authorized 
Mercedes-Benz Center as soon as possible.
The yellow ESP® warning lamp 
flashes when the engine is running.The ESP® or traction control has 
come into operation because of 
detected traction loss in at least 
one tire.
The cruise control is deactivated.When driving off, apply as little throttle as 
possible.
While driving, ease up on the accelerator.
Adapt your speed and driving to the prevailing 
road and weather conditions.
Do not deactivate the ESP®.
Exceptions: (
page 86).
Failure to follow these instructions increases the 
risk of an accident. 
     
        
        Page 354 of 473

353 Practical hints
What to do if …
ProblemPossible cause/consequenceSuggested solution
4The yellow fuel reserve warning lamp 
flashes after starting the engine.The fuel cap is not closed properly.Close the fuel cap.
The yellow fuel reserve warning lamp 
comes on when the engine is 
running.
Additionally you see the message 
Reserve fuel in the multifunction 
display.
The fuel level has gone below the 
reserve mark.Refuel at the next gas station (page 291).
After refueling you will see the message 
1 message in the multifunction display.
Press reset buttonJto confirm the 
message (
page 26).
1The red SRS indicator lamp comes 
on when the engine is running.There is a malfunction in the 
restraint systems. The air bags or 
emergency tensioning devices 
(ETDs) could deploy unexpectedly or 
fail to deploy in an accident.Drive with added caution to the nearest 
authorized Mercedes-Benz Center.
Warning!G
In the event a malfunction of the SRS is 
indicated as outlined above, the SRS may 
not be operational. For your safety, we 
strongly recommend that you contact an 
authorized Mercedes-Benz Center 
immediately to have the system checked;
otherwise the SRS may not be deployed 
when needed in an accident, which could 
result in serious or fatal injury, or it might 
deploy unexpectedly and unnecessarily 
which could also result in an accident 
and/or injury to you or to others. 
     
        
        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).  
     
        
        Page 368 of 473

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) 
     
        
        Page 371 of 473

370 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
•The cooling fan for the coolant is 
malfunctioning.Observe the coolant temperature display 
(
page 127).
If the coolant temperature is below 120°C, 
you may continue driving to the nearest 
specialist workshop.
Avoid heavy loads on the engine (e.g. by 
driving uphill) as well as stop-and-go traffic.
Have the fan replaced as soon as possible.
/Top up coolant
See Oper. ManualThe coolant level is too low.Add coolant (page 300).
Comply with all warnings while doing so.
If you have to add coolant frequently, 
have the cooling system checked by an au-
thorized Mercedes-Benz 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 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 engine 
damage. 
     
        
        Page 373 of 473
372 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
NCheck oil level
when next refuelingSLK 280 and SLK 350 only:
The engine oil level has dropped to 
a critical level.Check the engine oil level (page 296) and 
add engine oil as required (
page 299).
If you must add engine oil frequently, have 
the engine checked for possible leaks.
USA only:
Add 1 qt. engine oil
when next refueling
Canada only:
Add 1 liter engine oil
when next refueling
SLK 55 AMG only:
The engine oil level is too low.Add engine oil (page 299) and check the 
engine oil level (
page 296).
Cannot measure
motor oil levelSLK 55 AMG only:
The measuring system is malfunc-
tioning.Have the measuring system checked by an 
authorized Mercedes-Benz Center. 
     
        
        Page 374 of 473

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.