Page 374 of 491

373 Practical hints
What to do if …
Symbol messagesDisplay symbol
Display messages
Possible cause
Possible solution
#
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 
authorized Mercedes-Benz Center. 
Adjust driving to be consistent with 
reduced braking responsiveness. 
     
        
        Page 375 of 491

374 Practical hintsWhat to do if …Display symbol
Display messages
Possible cause
Possible solution
#
Battery/Alternator
Stop vehicle
The battery is malfunctioning.
The SBC brake system requires electrical 
energy and therefore has only limited op-
eration. Considerably greater brake pedal 
force is required and the stopping dis-
tance is increased. 
Stop the vehicle as soon as it is safe 
to do so. Adjust driving to be consis-
tent with reduced braking responsive-
ness.
Notify an authorized Mercedes-Benz 
Center. 
Low voltage
Start engine
The battery has insufficient voltage.
Start the engine (
page 47).
Malfunction
Electrical consumers 
switched off
The consumer battery has insufficient 
voltage and can no longer supply the con-
venience functions such as seat ventila-
tion*.
The electrical consumers will come back 
online as soon as on-board voltage is suf-
ficient.
(
Backrest, right rear
not locked
The rear seat backrest is not engaged.
Adjust the rear seat backrest until it is 
fully engaged in position.
Backrest, left rear
not locked
The rear seat backrest is not engaged.
Adjust the rear seat backrest until it is 
fully engaged in position. 
     
        
        Page 426 of 491

425 Practical hints
Batteries
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 305).
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 main-
tenance intervals or contact an 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.
Warning!
G
The SBC brake system requires electrical 
power to operate.
A malfunction in the vehicle’s power supply 
or electrical system may impair brake sys-
tem operation and switch it into its emer-
gency operation mode. The same applies if 
battery is disconnected. To brake, the driver 
must then apply significantly greater brake 
pedal pressure and depress the pedal much 
further to obtain the expected braking ef-
fect. If necessary, apply full pressure to the 
brake pedal. Brakes may only be applied to 
the front wheels. Stopping distance is in-
creased! Adjust your driving style according-
ly. For more information, refer to “SBC brake 
system” (
page 92). 
     
        
        Page 442 of 491
441 Technical data
Layout of poly-V-belt drive
Layout of poly-V-belt drive
E320/E500
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulley 
     
        
        Page 448 of 491
447 Technical data
Electrical system
Electrical system
Model
E320/E3204MATIC
E 500
1/E 500 4MATIC
1Not available in the U.S.Generator (alternator)
14 V / 150 A
14 V / 150 A
Starter motor
14 V / 1.4 kW
14 V / 1.7 kW
Battery (auxiliary)
12 V / 12 Ah
12 V / 12 Ah
Battery (main)
12 V/95 Ah
12 V / 95 Ah
Spark plugs
Bosch F8 DPP 332U
NGK PFR 5R-11
Bosch F8 DPP 332U
NGK PFR 5R-11
Electrode gap
0.039 in (1.00 mm)
0.039 in (1.00 mm)
Tightening torque
18.5 - 22 lb-ft (25 - 30 Nm)
18.5 - 22 lb-ft (25 - 30 Nm) 
     
        
        Page 463 of 491

462 Technical termsMaintenance System (U.S. vehicles)
Maintenance service indicator in the 
multifunction display that informs the 
driver when the next vehicle mainte-
nance service is due. The Vehicle Main-
tenance System in your vehicle tracks 
distance driven and the time elapsed 
since your last maintenance service, 
calculates other maintenance service 
work required, and calls for the next 
maintenance service accordingly.
Maximum load rating
(
page 333)
Maximum loaded vehicle weight
(page 333)
Maximum tire inflation pressure
(page 334)
Memory function*
Used to store three individual seat, 
steering wheel and exterior mirror posi-
tions for each SmartKey.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
The display field in the instrument clus-
ter used to present information provid-
ed by the control system.
Multifunction steering wheel
Steering wheel with buttons for operat-
ing the control system.
Normal occupant weight
(
page 334)Overspeed range
Engine speeds within the red marking 
on the tachometer dial. Avoid this en-
gine  sp ee d ra nge , a s  i t m ay  re sul t in s e-
rious engine damage that is not 
covered by the Mercedes-Benz Limited 
Warranty.
Poly-V-belt drive
Drives engine-components (alternator, 
AC compressor, etc.) from the engine.