Page 320 of 440

320 Practical hintsWhat to do if …?Symbol messagesDisplay symbol
Display message
Possible cause
Possible solution
#
Undervoltage
Charge battery
The battery has insufficient voltage.
Start the engine (
page 43).
Undervoltage
Switch off
consumers
The battery has insufficient voltage.
Turn off unnecessary electrical con-
sumers.
VISIT WORKSHOP!
The battery was charged with a battery 
charger or jump started.
Have the battery checked at a service 
station. 
The battery is no longer charging.
Possible causes:
alternator malfunctioning
broken poly-V-belt
Do not forget that the brake system re-
quires electrical energy and may be oper-
ating with restricted capability. 
Considerably greater brake pedal force is 
required and the stopping distance is in-
creased.
Stop immediately and check the 
poly-V-belt.
If it is broken:
Do not continue to drive. Otherwise 
the engine will overheat due to an in-
operative water pump which may re-
sult in damage to the engine. Notify an 
authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest au-
thorized Mercedes-Benz Center. Ad-
just driving to be consistent with 
reduced braking responsiveness. 
     
        
        Page 363 of 440

363 Practical hints
Battery
Battery
The battery is located on the right side of 
the engine compartment.
Removal of filter box:
Release the three clamps1.
Remove filter box.
Installation of filter box:
Insert filter box properly.
Secure it with the three clamps1.
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, 
see “Battery” (
page 288).
Never lean over batteries while connecting, 
you might get injured.
Battery fluid contains sulfuric acid. Do not 
allow this fluid to come in contact with eyes, 
skin or clothing. In case it does, immediately 
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.
!Never loosen or detach battery termi-
nal clamps while the engine is running 
or the SmartKey is in the starter switch. 
Otherwise the alternator and other 
electronic components could be se-
verely damaged.
Have the battery checked regularly by 
an authorized Mercedes-Benz Center.
Refer to Service Booklet for mainte-
nance intervals or contact your autho-
rized Mercedes-Benz Center for further 
information.Warning!
G
Do not place metal objects on the battery as 
this could result in a short circuit. 
Use leak-proof battery only to avoid the risk 
of acid burns in the event of an accident. 
     
        
        Page 379 of 440
379 Technical data
Layout of poly-V-belt drive
Layout of poly-V-belt drive
CLK 320/CLK 500/CLK 55 AMG
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulley 
     
        
        Page 385 of 440
385 Technical data
Electrical system
Electrical system
Model
CLK 320
CLK 500
CLK 55 AMG
Generator (alternator)
14 V/120 A
14 V/150 A
14 V/150 A
Starter motor
14 V/1.4 KW
14 V/1.7 KW
14 V/1.7 KW
Battery
12 V/100 Ah
12 V/100 Ah
12 V/100 Ah
Spark plugs
Bosch F8 DPP 332
NGK PFR 5R-11
Bosch F8 DPP 332
NGK PFR 5R-11
NGK ILFR 6A
Electrode gap
0.039 in (1.00 mm)
0.039 in (1.00 mm)
0.031 in (0.8 mm)
Tightening torque
18.5 - 22 lb-ft (25 - 30 Nm)
18.5 - 22 lb-ft (25 - 30 Nm)
18.5 - 22 lb-ft (25 - 30 Nm) 
     
        
        Page 400 of 440

400 Technical termsMemory function*
Used to store three individual seat, 
steering wheel and mirror positions for 
each SmartKey or, if so equipped, 
KEYLESS-GO* feature.
Menu
The control system displays are ar-
ranged in menus. Each menu contains 
a number of commands for particular 
systems. In the Audio menu, for exam-
ple, you will find the commands 
Select 
radio station 
or Operate CD player
. 
Using commands, you can directly 
change the settings for your vehicle.
MON
(M
otor O
ctane N
umber)
The Motor Octane Number for gasoline 
as determined by a standardized meth-
od. It is an indication of a gasoline's 
ability to resist undesired detonation 
(knocking). The average of both the 
MON (Motor Octane Number) and 
->RON (Research Octane Number) is 
posted at the pump, also known as 
ANTI-KNOCK INDEX.Multifunction display
Display field in the speedometer used 
to present information provided by the 
control system.
Multifunction steering wheel
Steering wheel with buttons for operat-
ing the control system.
Overspeed range
Engine speeds within the red marking 
on the tachometer dial. Avoid this en-
gine speed range, as it may result in se-
rious engine damage that is not 
covered by the Mercedes-Benz Limited 
Warranty.
Parktronic (Parking assist)*
System which uses visual and acoustic 
signals to assist the driver during park-
ing maneuvers.
Poly-V-belt drive
Drives engine-components (alternator, 
AC compressor, etc.) from the engine.Power train
Collective term designating all compo-
nents used to generate and transmit 
motive power to the drive axles, includ-
ing
engine
clutch/torque converter
transmission
transfer case
drive shaft
differential
axle shafts/axles
Program mode selector switch
Used to switch the automatic transmis-
sion between regular operationS and 
comfort operationC.
CLK 55 AMG with steering wheel gear-
shift control and manual shift program: 
In addition toS andC (for regularS or 
comfortC operation, see above) you 
can use theM for manual shift 
program.