Page 383 of 539

382 Practical hintsWhat to do if …Lamps in instrument clusterGeneral information:
If any of the following lamps in the instru-
ment cluster fails to come on during thebulb self-check when switching on the igni-
tion, have the respective bulb checked and 
replaced if necessary.Problem
Possible cause
Suggested solution
-
The yellow ABS indicator lamp 
comes on while the engine is 
running.
ABS has detected a malfunction and has 
switched off. The BAS, ESP
®, and 4-ETS are 
also switched off (see messages in multifunc-
tion display).
The brake system is still functioning normally 
but without the ABS available.
If the ABS control unit is malfunctioning, 
other systems such as the navigation 
system* or the automatic transmission may 
also be malfunctioning.
Continue driving with added caution. 
Wheels may lock during hard braking, 
reducing steering capability.
Read and observe messages in the 
multifunction display (
page 395).
Have the system checked at an 
authorized Mercedes-Benz Light 
Truck Center as soon as possible.
Failure to follow these instructions 
increases the risk of an accident.
The charging voltage has fallen below 
ten volts. The ABS has switched off.
The battery might not be charged sufficiently.
Switch off electrical consumers that 
are currently not needed, e.g. seat 
heating*.
If necessary, have the generator 
(alternator) and the battery checked.
When the voltage is above this value 
again, the ABS is operational again. 
     
        
        Page 399 of 539

398 Practical hintsWhat to do if …Display message
Possible cause
Possible solution
ABS
unavailable
See Operator’s Manual
The ABS was deactivated because of 
insufficient power supply. The charg-
ing voltage has fallen below ten 
volts.
The brake system is still functioning 
normally but without the ABS 
available.
Switch off electrical consumers that are 
currently not needed, e.g. seat heating*.
If necessary, have the generator 
(alternator) and the battery checked.
When the voltage is above this value again, the 
ABS is operational again and the message in 
the multifunction display should disappear.
Battery
protection
Convenience functs.
Temporarily
Unavailable
The battery has insufficient voltage 
and can no longer supply conve-
nience functions such as the rear 
window defroster.
As soon as the on-board voltage is sufficient, 
the consumers will switch on again.
Please note:
Convenience Functions
Available again
On-board voltage is sufficient; the 
consumers will switch on again.
Cruise 
control
Drive to workshop
Cruise control is malfunctioning.
Have cruise control checked by an 
authorized Mercedes-Benz Light Truck 
Center.
DSR
Malfunction
Downhill Speed Regulation is 
malfunctioning.
Have the Downhill Speed Regulation 
checked by an authorized Mercedes-Benz 
Light Truck Center. 
     
        
        Page 408 of 539

407 Practical hints
What to do if …
Symbol messagesDisplay symbol
Display messages
Possible cause
Possible solution
#
Undervoltage
Switch off consumers
The battery has insufficient volt-
age.
Turn off unnecessary electrical 
consumers.
malfunction
Visit workshop
The battery was charged with a 
battery charger or jump started.
Have the battery checked at a service 
station.
Battery/Alternator
Stop vehicle
The battery is no longer charg-
ing.
Possible causes:
alternator malfunctioning
broken poly-V-belt
Do not forget that the brake sys-
tem requires electrical energy 
and may be operating with re-
stricted capability. Considerably 
greater brake pedal force is 
required and the stopping dis-
tance is increased.
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 inoperative 
water pump which may result in damage 
to the engine. Notify an authorized 
Mercedes-Benz Light Truck Center.
If it is intact:
Drive immediately to the nearest autho-
rized Mercedes-Benz Light Truck Center. 
Adjust driving to be consistent with re-
duced braking responsiveness. 
     
        
        Page 465 of 539

464 Practical hintsBattery
Disconnecting, removing, reinstalling and reconnecting the battery
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 462).
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 Light 
Truck Center.
Refer to Maintenance Booklet for main-
tenance intervals or contact your au-
thorized Mercedes-Benz Light Truck 
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
Disconnecting, removing, reinstalling and 
reconnecting the battery is a complicated 
and technically demanding procedure that 
also requires safety precautions to avoid the 
r i s k  o f  i n j u r y .  W e  s t r o n g l y  r e c o m m e n d  t h a t  i t  
be performed by a qualified technician only. 
Please read the instructions fully before 
beginning operation and only undertake it if 
you feel fully capable of performing all of the 
tasks involved as described in these instruc-
tions. Observe all safety instructions and 
precautions when handling automotive bat-
teries (
page 462). Performing the tasks 
involved incorrectly can cause damage to 
the vehicle and impair the operating safety 
o f  t h e  v e h i c l e ,  a n d / o r  c a u s e  s e v e r e  i n j u r y  t o  
you or others. 
     
        
        Page 486 of 539
485 Technical data
Layout of poly-V-belt drive
Layout of poly-V-belt drive
ML 350
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator)
ML 500
1Automatic belt tensioner
2Power steering pump
3Air conditioning compressor
4Crankshaft
5Coolant pump
6Generator (alternator)
7Idler pulley 
     
        
        Page 491 of 539
490 Technical dataElectrical systemModel
ML 350
ML 500
Generator (alternator)
14 V/180 A
14 V/180 A
Starter motor
12 V/1.4 kW
12 V/1.7 kW
Battery
12 V/70 Ah
12 V/95 Ah
Spark plugs
NGK PLKR 6A
NGK PFR 5R-11
Electrode gap
0.031 in (0.8 mm)
0.039 in (1.0 mm)
Tightening torque
15 – 22 lb-ft (20 – 30 Nm)
15 – 22 lb-ft (20 – 30 Nm) 
     
        
        Page 505 of 539

504 Technical termsMaximum tire inflation pressure
(
page 366)
Modular COMAND System
Information and operating center for 
vehicle sound and communications 
systems, including the radio and the ra-
dio and navigation system, as well as 
for other optional equipment (CD 
changer, telephone, etc.).
Memory function*
Used to store three individual seat, 
steering wheel and exterior mirror 
positions.
MON
(Motor 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 366)
OCS
(Occupant C
lassification S
ystem) 
The system automatically turns the 
front passenger front air bag on or off 
based on the classified occupant size 
category determined by weight sensor 
readings from the seat.
Overspeed range
Engine speeds within the red marking 
on 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.Parktronic (Parking assist)*
System which uses visual and acoustic 
signals to assist the driver during park-
ing maneuvers.
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/axles