Page 347 of 473

346 Practical hints
What to do if …
Lamps in instrument clusterGeneral information:
If any of the following lamps in the instru-
ment cluster fails to come on during thebulb self-check when switching on ignition 
(
page 37), have the respective bulb 
checked and replaced if necessary.
ProblemPossible cause/consequenceSuggested solution
-The yellow ABS indicator lamp comes on 
when the engine is running.The ABS has detected a malfunction 
and has switched off. The BAS and 
ESP
® are also switched off (see mes-
sages in the multifunction display).
The brake system is still functioning 
normally but without the systems 
specified above.
If the ABS control unit is malfunction-
ing, other systems such as the naviga-
tion system* or the automatic 
transmission* may also be malfunc-
tioning.
Continue driving with added caution. 
Wheels may lock during hard braking, 
reducing steering capability.
Read and observe messages in the 
multifunction display (
page 356).
Have the system checked at an 
authorized Mercedes-Benz Center as 
soon as possible.
Failure to follow these instructions in-
creases the risk of an accident.
The charging voltage has fallen below 
10 volts. The ABS has switched off.
The battery might not be charged suf-
ficiently.When the voltage is above this value 
again, the ABS is operational again an the 
ABS indicator lamp should go out.
If the ABS indicator lamp does not go out:
Have the generator (alternator) and 
battery checked. 
     
        
        Page 360 of 473

359 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
ESPunavailable
See Operator’s ManualThe ESP® is temporarily not available.
The system’s self-diagnosis may not 
be completed yet.
The ABS and the BAS might not be 
operational.
The brake system is still functioning 
normally but without the systems 
specified above.Drive a short distance with added 
caution at a vehicle speed of above 
12 mph (20 km/h).
When the message disappears, the ESP
® is 
available again.
If the message does not disappear:
Continue driving with added caution.
Have the system checked at an authorized 
Mercedes-Benz Center as soon as possible.
Failure to follow these instructions increases 
the risk of an accident.
The charging voltage has fallen below 
10 volts. The ESP® has switched off.
The BAS may be switched off, too. The 
battery may not be charged. The bat-
tery or the generator may be malfun-
tioning.
The ABS might not be operational.
The brake system is still functioning 
normally but without the systems 
specified above.
Continue driving with added caution.
When the voltage is above this value again, the 
ESP
® is operational again and the message in 
the multifunction display should disappear.
If the message in the multifunction display 
does not disappear:
Have the generator (alternator) and battery 
checked.
Have the system checked at an authorized 
Mercedes-Benz Center as soon as possible. 
     
        
        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 416 of 473

415 Practical hints
Battery
Battery
The battery is located in the engine com-
partment on the right-hand side below the 
water tray (
page 416).
1Battery
2Positive terminal
3Negative terminal
Warning!G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and precau-
tions when handling automotive batteries 
(
page 303).
Never lean over batteries while connecting 
them, as you could otherwise be injured.
Battery fluid contains sulfuric acid. Do not 
allow this fluid to come into contact with 
eyes, skin or clothing. In case it does, imme-
diately flush affected area with water and 
seek medical help if necessary.
A battery will also produce hydrogen gas, 
which is flammable and explosive. Keep 
flames or sparks away from battery, avoid 
improper connection of jumper cables, 
smoking, etc.
Warning!G
Do not place metal objects on the battery as 
this could result in a short circuit.
Use leak-proof batteries only to avoid the 
risk of acid burns in the event of an 
accident.
!Never loosen or detach battery terminal 
clamps while the engine is running or the 
SmartKey is in the starter switch. Otherwise the 
alternator and other electronic components 
could be severely damaged.
Have the battery checked regularly by an 
authorized Mercedes-Benz Center.
Refer to Maintenance Booklet for maintenance 
intervals or contact an authorized 
Mercedes-Benz Center for further information. 
     
        
        Page 433 of 473
432 Technical data
Layout of poly-V-belt drive
SLK 280, SLK 350
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator)SLK 55 AMG
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulley 
     
        
        Page 441 of 473
440 Technical data
Electrical system
ModelSLK 280SLK 350SLK 55 AMG
Generator (alternator)14 V/150 A14 V/150 A14 V/150 A
Starter motor12 V/1.4 kW12 V/1.4 kW12 V/1.7 kW
Battery12 V/74 Ah12 V/74 Ah12 V/74 Ah
Spark plugsNGK PLKR 6ABosch Platin Y 7 MPP33
NGK PLKR 6ANGK IFR6D10
Electrode gap0.031 in (0.8 mm)0.031 in (0.8 mm)0.039 in (1.0 mm)
Tightening torque15 – 22 lb-ft (20 – 30 Nm)15 – 22 lb-ft (20 – 30 Nm)18 – 22 lb-ft (25 – 30 Nm)