Page 302 of 416
302 Practical hintsWhat to do if …Symbol messagesDisplay symbol
Display message
Possible cause
Possible solution
#
BATTERY/ALTERNATOR
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
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 serious engine damage not
covered by the Mercedes-Benz Limited
Warranty. Notify an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Turn off unnecessary electric consum-
ers.
Drive immediately to the nearest
authorized Mercedes-Benz Light Truck
Center.
UNDERVOLTAGE
ENGINE ON!
The battery has insufficient voltage.
Start the engine.
Page 352 of 416

352 Practical hintsBatteryHave the battery removed at a
Mercedes-Benz Light Truck Center.
If you charge the battery yourself, make
sure to comply with the operating instruc-
tions for your battery charger.
Disconnecting the battery
Read and observe safety instructions
and precautions (
page 351).
Turn off all electrical consumers.
Disconnect the battery negative lead.
Remove the cover from the positive ter-
minal.
Disconnect the battery positive lead.
Remove the breather hose from the
battery.
!Have the battery checked regularly by
an authorized Mercedes-Benz Light
Truck Center.
Refer to Maintenance Booklet for main-
tenance intervals or contact an autho-
rized Mercedes-Benz Light Truck
Center for further information.
!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.
Warning!
G
With a disconnected battery
you will no longer be able to turn the
SmartKey in the starter switch
the gear selector lever will remain
locked in position
P
Page 367 of 416
367 Technical data
Layout of poly-V-belt drive
Layout of poly-V-belt drive
For dimensions of the poly-V-belt, see
technical data (
page 368).
G 500
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulley
G55AMGThe G 55 AMG has two poly-V-belts
(belt one shown in purple/belt two shown
in black).1Idler pulley
2Automatic belt tensioner
3Power steering pump
4Air conditioning compressor
5Crankshaft
6Coolant pump
7Generator (alternator)
8Idler pulley
9Automatic belt tensioner
aSupercharger
Page 372 of 416
372 Technical dataElectrical system
G 500
G55AMG
Generator (alternator)
14 V/150 A
14 V/180 A
Starter motor
12 V/1.7 kW
12 V/1.7 kW
Battery
12 V/90 Ah
12 V/90 Ah
Spark plugs
Bosch F 8 DPER
Beru 14 FGH 8 DPUR X 2
NGK ILFR6A
Electrode gap
0.039 in (1.0 mm)
0.039 in (1.0 mm)
Tightening torque
15 – 22 lb-ft (20 – 30 Nm)
15 – 22 lb-ft (20 – 30 Nm)
Page 384 of 416

384 Technical termsMemory function*
Used to store three individual seat,
steering wheel and mirror positions 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
A display field in the instrument cluster
used to present information provided
by the control system.
Normal occupant weight
(
page 272)Overspeed range
Engine speeds within the red marking
of 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.
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/axlesProduction options weight
(
page 272)
PSI
(Pounds per square i
nch)
(
page 272)
Recommended tire inflation pressure
(page 272)
Rear Parking Assist*
System which uses visual and acoustic
signals to assist the driver during park-
ing maneuvers.
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.
Restraint system
Seat belts, belt tensioner, airbags and
child seat restraint systems. As inde-
pendent systems, their protective func-
tions complement one another.