Page 390 of 509

389 Practical hints
What to do if …?
Text messages
Display Possible cause/consequencePossible solution
ABS and ESP
Currently Unavailable
See Operator’s ManualABS and ESP® are not available due to a malfunction. 
BAS and the hill start assist are also switched off. It 
is possible that the self-diagnostics have not yet 
been completed. 
The brake system still functions normally.Drive a short distance with gentle turns above a 
speed of 12 mph (20 km/h).
The message disappears when ABS and ESP
® 
are again available.
The ABS and ESP® were deactivated because of in-
sufficient power supply. The charging voltage has 
fallen below 10 volts. BAS and the hill start assist are 
also deactivated.
The brake system still functions normally but without 
the ABS and ESP
® available.
When the voltage is above this value again, the ABS 
and ESP® are 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 the battery 
checked.
ABS and ESP
Inoperative
See Operator’s ManualABS and ESP® are switched off due to a malfunction. 
BAS and the hill start assist are also switched off.
The brake system still functions normally but without 
the ABS and ESP
® available.
Continue driving with added caution. Wheels 
may lock during hard braking, reducing steering 
capability.
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. 
     
        
        Page 398 of 509

397 Practical hints
What to do if …?
Symbol messages
Display Possible cause/consequencePossible solution
-ABS and ESP
Currently Unavailable
See Operator’s ManualABS and ESP® are not available due to a 
malfunction. BAS and the hill start assist 
are also switched off. It is possible that the 
self-diagnostics have not yet been complet-
ed. 
The brake system still functions normally.Drive a short distance with gentle turns 
above a speed of 12 mph (20 km/h).
The message disappears when ABS and 
ESP
® are again available.
The ABS and ESP® were deactivated be-
cause of insufficient power supply. The 
charging voltage has fallen below 10 volts. 
BAS and the hill start assist are also deacti-
vated.
The brake system still functions normally 
but without the ABS and ESP
® available.
When the voltage is above this value again, 
the ABS and ESP® are 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 the 
battery checked. 
     
        
        Page 400 of 509
399 Practical hints
What to do if …?
Display Possible cause/consequencePossible solution
#The battery is no longer charging.
Possible causes:
alternator malfunctioning
broken poly-V-belt
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 en-
gine will overheat due to an inoperative water 
pump which may result in damage to the en-
gine. 
Notify an authorized Mercedes-Benz Center.
If it is intact:
Drive immediately to the nearest authorized 
Mercedes-Benz Center.
There is a malfunction in the electronic sys-
tem.Have the system checked at an authorized 
Mercedes-Benz Center as soon as possible.
2Check
Brake Pad WearThe brake pads have reached their wear 
limit.Have the brake pads replaced as soon as 
possible. 
!Brake pad thickness must be visually 
checked by a qualified technician at the intervals 
specified in the Maintenance Booklet. 
     
        
        Page 448 of 509

447 Practical hints
Battery
1Filter box
2Clamps
Removing filter box: Release 
clamps2.
Remove filter box.
Installing filter box: Insert filter box 
properly.
Secure it with clamps2.
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 446).
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 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 at an autho-
rized 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 batteries only to avoid the 
risk of acid burns in the event of an 
accident.
!Do not connect any consumers directly to 
the battery or it will be discharged. 
     
        
        Page 465 of 509
464 Technical data
Layout of poly-V-belt drive
C 300/C 350
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator) 
     
        
        Page 474 of 509
473 Technical data
Electrical system
Electrical system
ModelC 2301
C 230 Sport1
C 230 4MATIC1
C 230 4MATIC Sport1
1Canada only.
C 300
C 300 Sport 
C 300 4MATIC
C 300 4MATIC SportC 3501
C 350 Sport
C 350 4MATIC1
C 350 4MATIC Sport1
Generator (alternator)14 V/150 A14 V/150 A14 V/150 A
Starter motor12 V/1.4 kW12 V/1.4 kW12 V/1.4 kW
Battery12 V/84 Ah12 V/84 Ah12 V/84 Ah
Spark plugsNGK PLKR 6A 
Bosch Platin Y 7 MPP 33NGK PLKR 6A 
Bosch Platin Y 7 MPP 33NGK PLKR 6A 
Bosch Platin Y 7 MPP 33
Electrode gap0.031 in (0.8 mm)0.031 in (0.8 mm)0.031 in (0.8 mm)
Tightening torque15 – 22 lb-ft (20 – 30 Nm)15 – 22 lb-ft (20 – 30 Nm)15 – 22 lb-ft (20 – 30 Nm)