304 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagePossible causePossible 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. 
369 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 370).
G500
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulleyG55AMG
The 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 
386 Technical terms
Memory function*
Used to store three individual seat, 
steering wheel and mirror positions for 
each SmartKey.
MON
(M
otor Octane Number)
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 274)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 275)
PSI
(P
ounds per square inch)
(
page 275)
Recommended tire inflation pressure
(
page 275)
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.