2008 MERCEDES-BENZ R320 alternator

414 Practical hints
What to do if …
Lamps in instrument clusterGeneral information:
If any of the following lamps in the instru-
ment cluster fails to come on during the bulb self-check when switching on the
ignition, have the respective bulb checked
and replaced if necessary.
ProblemPossible cause/consequenceSuggested solution
-The yellow ABS indicator lamp
comes on while the engine is
running.ABS has detected a malfunction and has
switched off. The BAS and the ESP® are also
switched off (see messages in multifunction
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 427).
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
10 volts. The ABS has switched off.
The battery might not be charged sufficiently.When the voltage is above this value
again, the ABS is operational again and
the ABS indicator lamp should go out.
If the ABS indicator lamp does not go out:
Have the generator (alternator) and
the battery checked.

436 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
ESPUnavailable
See Operator’s ManualThe ESP® was deactivated because
of insufficient power supply. The
charging voltage has fallen below
10 volts.
The brake system is still functioning
normally but without the ESP
®
available.
When the voltage is above this value again, the
ESP® is operational again and the message in
the multifunction display should disappear.
If the message in the multifunction display
does not disappear:
Have the generator (alternator) and the
battery checked.
Have the system checked at an authorized
Mercedes-Benz Light Truck Center as soon
as possible.
If the yellow ESP® warning
lampv flashes while driving
and this message appears, the
Electronic Traction System has
switched off to prevent overheating
of the drive wheel brakes.As soon as the brakes have cooled off, the
Electronic Traction System switches on again.
The message in the multifunction display disap-
pears and the ESP
® warning lampv goes
out.
The self-diagnosis has not been
completed yet.The display will clear after driving a short
distance at a vehicle speed of above
12 mph (20 km/h).

444 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
òReplace air filter.The air filter is clogged.Have the air filter checked by an autho-
rized Mercedes-Benz Light Truck Center.
#The battery is no longer charg-
ing.
Possible causes:

alternator malfunctioning

broken poly-V-belt
Do not forget that the brake
system requires electrical
energy and may be operating
with restricted capability.
Considerably greater brake
pedal force is required and the
stopping distance is increased.
Stop the vehicle in a safe location or as
soon as it is safe to do so 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.
Contact an authorized
Mercedes-Benz Light Truck Center.
If it is intact:
Contact an authorized
Mercedes-Benz Light Truck Center
immediately. Adjust driving to be
consistent with reduced braking
responsiveness.

445 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
#Battery/Alternator
Stop VehicleThe battery is defective.Stop the vehicle in a safe location or as
soon as it is safe to do so.
Apply the parking brake (page 65).
Do not continue to drive.
Contact an authorized Mercedes-Benz
Light Truck Center.
2Brake WearThe brake pads have reached
their wear limit.Have the brake pads replaced as soon as
possible.
!Brake pad thickness must be visually in-
spected by a qualified technician at the intervals
specified in the Maintenance Booklet.

505 Practical hints
Battery
Disconnecting, removing, reinstalling
and reconnecting the battery
Step 1 (Disconnecting)
Set the automatic transmission to
positionP (
page 192).
Firmly depress the parking brake
(
page 65).
Turn off the engine (page 66).
Leave the ignition switched on
(
page 39).
!Never loosen or detach battery terminal
clamps while the engine is running or the
SmartKey is in the starter switch. Otherwise the
alternator and other electronic components
could be severely damaged.
Have the battery checked regularly by an autho-
rized Mercedes-Benz Light Truck Center.
Contact your authorized 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
risk of injury. We strongly recommend that it
be performed by a qualified technician or an
authorized Mercedes-Benz Light Truck
Center 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 instructions. Observe all
safety instructions and precautions when
handling automotive batteries
(
page 503). Performing the tasks involved
incorrectly can cause damage to the vehicle
and impair the operating safety of the
vehicle, and/or cause severe injury to you
or others.
iWith a disconnected battery you will no
longer be able to turn the SmartKey in the
starter switch and pressing the KEYLESS-GO*
start/stop button will have no effect.
iIf your battery is discharged, the vehicle
must be jump started (
page 511) using the
jump start contacts in the engine compartment,
or an accessory battery charge unit* approved
by Mercedes-Benz must be connected using the
jump start contacts in the engine compartment
(see separate instructions for the accessory
battery charge unit*) before any of the following
steps can be performed. If the battery cannot be
jumped or charged, please contact an autho-
rized Mercedes-Benz Light Truck Center.


526 Technical data
Layout of poly-V-belt drive
R 320 CDI 4MATIC
1Coolant pump
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Idler pulley
8Generator (alternator)R 350, R 350 4MATIC, R 550 4MATIC
1Idler pulley
2Idler pulley
3Automatic belt tensioner
4Power steering pump
5Air conditioning compressor
6Crankshaft
7Coolant pump
8Generator (alternator)

533 Technical data
Electrical system
Electrical system
ModelR 3501
R 350 4MATIC
1USA only.
R 550 4MATIC2
2Canada only.
Generator (alternator)14 V/150 A14 V/180 A
Starter motor12 V/1.4 kW12 V/1.7 kW
Battery12 V/70 Ah12 V/95 Ah
Spark plugsBosch Y7MPP33NGK PLKR7A
Electrode gap0.031 in (0.8 mm)0.031 in (0.8 mm)
Tightening torque15 - 19 lb-ft (20 - 25 Nm)15 - 19 lb-ft (20 - 25 Nm)
ModelR 320 CDI 4MATIC
Generator (alternator)14 V/180 A
Starter motor12 V/2.0 kW
Battery12 V/95 Ah