Page 265 of 376
265 Practical hints
What 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 au-
thorized Mercedes-Benz Light Truck
Center.
UNDERVOLTAGE
ENGINE ON!
The battery has insufficient voltage.
Start the engine.
Page 312 of 376

312 Practical hintsBatteryDisconnecting the battery
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.
Reconnecting the battery
Turn off all electrical consumers.
Connect the positive lead and fasten its
cover.
Connect the negative lead.
Install the breather hose.
!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.
iWith 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 positionP
!Never invert the terminal connections.!The battery, its filler caps and the vent
tube must always be securely installed
when the vehicle is in operation.
iThe following procedures must be car-
ried out following any interruption of
battery power (e.g. due to reconnec-
tion):
Set the clock (see COMAND opera-
tor’s manual).
Resynchronize the front seat head
restraints and seat adjustment fore,
aft (
page 95).
Synchronize the ESP (
page 263).
Page 327 of 376
327 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 328).
G500/G55AMG
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulley
Page 331 of 376
331 Technical data
Electrical system
Electrical system
G500
G55AMG
Generator (alternator)
14 V/150 A
14 V/150 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 PFR5R-11
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 346 of 376

346 Technical termsPoly-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
Rear Parking Assist*
System which uses visual and acoustic
signals to assist the driver during park-
ing maneuvers.Remote Vehicle Diagnostics
Transmission of vehicle data and cur-
rent location to the Mercedes-Benz
Customer Assistance Center for sub-
scribers to Tele Aid service.
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.RON
(R
esearch O
ctane N
umber)
The Research Octane Number for gaso-
line as determined by a standardized
method. It is an indication of a gaso-
line’s ability to resist undesired detona-
tion (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.
Shift lock
When the vehicle is parked, this lock
prevents the transmission gear selec-
tor lever from being moved out of
positionP without key turned and
brake pedal depressed.
SRS
(S
upplemental R
estraint S
ystem)
Seat belts, emergency tensioning de-
vice and airbags. Though independent
systems, they are closely interfaced to
provide effective occupant protection.