Page 375 of 506
374 Practical hintsWhat to do if …?Symbol messagesDisplay symbol
Display message
Possible cause
Possible solution
#
Visit Workshop!
The battery is no longer charging.
Possible causes:
broken poly-V-belt
alternator malfunctioning
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
inoperative water pump which may
result in damage to the engine. Notify
an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest
authorized Mercedes-Benz Center.
Undervoltage
Charge battery
The battery has insufficient voltage.
Start the engine (
page 46).
Undervoltage
Switch off
consumers
The battery has insufficient voltage.
Turn off unnecessary electrical con-
sumers.
Page 428 of 506

427 Practical hints
Battery
Battery
The battery is located in the engine
compartment on the right hand side.
1Clamps
Removing filter box:
Release clamps1.
Remove filter box.
Installing filter box:
Insert filter box properly.
Secure it with clamps1.
Warning!
G
Failure to follow these instructions can re-
sult in severe injury or death.
Observe all safety instructions and
precautions when handling automotive
batteries (
page 311).
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 Maintenance Booklet for
maintenance intervals or contact an
authorized 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 444 of 506
443 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 451 of 506
450 Technical dataElectrical systemModel
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 465 of 506

464 Technical termsMultifunction steering wheel
Steering wheel with buttons for operat-
ing the control system.
Normal occupant weight
(
page 337)
OCS
(Occupant C
lassification S
ystem)
The system automatically turns the
front passenger front air bag on or off
based on the classified occupant size
category determined by weight sensor
readings from the seat.
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
parking maneuvers.Poly-V-belt drive
Drives engine-components (alternator,
AC compressor, etc.) from the engine.
Power train
Collective term designating all
components used to generate and
transmit motive power to the drive
axles, including
engine
clutch/torque converter
transmission
transfer case
drive shaft
differential
axle shafts/axles
Production options weight
(
page 337)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.
PSI
(P
ounds per S
quare I
nch)
(
page 337)
Recommended tire inflation pressure
(page 337)
REST
(Residual engine heat utilization)
Feature that uses the engine heat
stored in the coolant to heat the vehi-
cle interior for a short time after the en-
gine has been turned off.