2008 MERCEDES-BENZ R320 light

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).

437 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
PShift to P or N
to start engine
.
You have attempted to start the
engine with the KEYLESS-GO*
start/stop button while the
automatic transmission was set
to positionR orD.Set the automatic transmission to
positionP orN.
Make sure the brake pedal is
depressed when attempting to start
the engine with the KEYLESS-GO*
start/stop button.
Only shift to P
when vehicle
is at a standstill.You have tried to shift the
automatic transmission into
position P using the gear selec-
tor lever although the vehicle
was still in motion.Stop the vehicle.
SRSRestraint Sys. Malfunction
Service RequiredThe system is malfunctioning.Drive with added caution to the near-
est authorized Mercedes-Benz Light
Truck Center.
Warning!G
In the event a malfunction of the SRS is indi-
cated as outlined above, the SRS may not be
operational. For your safety, we strongly
recommend that you contact an authorized
Mercedes-Benz Light Truck Center
immediately to have the system checked;
otherwise the SRS may not be activated
when needed in an accident, which could re-
sult in serious or fatal injury, or it might de-
ploy unexpectedly and unnecessarily which
could also result in injury.

439 Practical hints
What to do if …
Display messagePossible
cause/consequencePossible solution
Monitor the 59indicator lamp on the center console (page 81) and
the multifunction display in the instrument cluster (
page 29) for the following:
With the seat unoccupied and the ignition turned on,

the 59indicator lamp on the center console should illuminate and
remain illuminated, indicating that the OCS (
page 77) has deactivated the air
bag.

the message Front Passenger Airbag Enabled See Operator’s Manual or the
message
Front Passenger Airbag Disabled See Operator’s Manual should
not appear in the multifunction display at any time the seat is unoccupied. Wait
at least 60 seconds for the system to complete the necessary check cycles and
to make sure neither message appears in the multifunction display.
If above conditions are met, you can occupy the front passenger seat again.
Depending on the front passenger classification sensed by the OCS (
page 77),
the 59indicator lamp will remain illuminated or go out.
If above conditions are not met, the system is not working properly. Have the
system checked as soon as possible by an authorized Mercedes-Benz Light Truck
Center.
Warning!G
If the 59 indicator lamp re-
mains out even after performing the above
corrective steps, do not have any children
12 years old and under and other small individuals use the front passenger seat
until the system has been repaired.

441 Practical hints
What to do if …
Display messagePossible
cause/consequencePossible solution
Monitor the 59indicator lamp on the center console (page 81) and
the multifunction display in the instrument cluster (
page 29) for the following:
With the seat unoccupied and the ignition turned on,

the 59indicator lamp on the center console should illuminate and
remain illuminated, indicating that the OCS (
page 77) has deactivated the air
bag.

the message Front Passenger Airbag Enabled See Operator’s Manual or the
message
Front Passenger Airbag Disabled See Operator’s Manual should
not appear in the multifunction display at any time the seat is unoccupied. Wait
at least 60 seconds for the system to complete the necessary check cycles and
to make sure neither message appears in the multifunction display.
If above conditions are met, you can occupy the front passenger seat again.
Depending on the front passenger classification sensed by the OCS (
page 77),
the 59indicator lamp will remain illuminated or go out.
If above conditions are not met, the system is not working properly. Have the
system checked as soon as possible by an authorized Mercedes-Benz Light Truck
Center.
Warning!G
If the 59indicator lamp re-
mains out even after performing the above
corrective steps, do not have any children
12 years old and under and other small individuals use the front passenger seat
until the system has been repaired.

442 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Check tires,
then restart
Run Flat Indicator.
There was a warning message about
a loss in the tire inflation pressure
and the Run Flat Indicator has not
been reactivated yet.Make sure that the correct tire inflation pressure is set
for each tire.
Then restart the Run Flat Indicator (page 375).
Run Flat Indicator
InoperativeRun Flat Indicator is malfunctioning.Have the Run Flat Indicator checked by an authorized
Mercedes-Benz Light Truck Center.
Tire Pressure
Check TiresThe Run Flat Indicator indicates that
the pressure is too low in one or more
tires.Carefully bring the vehicle to a halt, avoiding abrupt
steering and braking maneuvers. Observe the traffic
situation around you.
Check and adjust tire inflation pressure as required
(
page 373).
If necessary, replace the wheel (page 492).
Restart the Run Flat Indicator after adjusting the tire
inflation pressure values (
page 375).
Tire pressure
displayed after
driving for
a few minutes
.
Vehicles with Advanced TPMS*:
The tire inflation pressure is being
checked.Drive the vehicle for a few minutes.

443 Practical hints
What to do if …
Display messagePossible cause/consequencePossible solution
Tire Pressure Monitor
InoperativeThe TPMS or Advanced TPMS* is
malfunctioning.Have the TPMS or Advanced TPMS* checked by an
authorized Mercedes-Benz Light Truck Center.
Tire Pressure Monitor
Inoperative
No Wheel SensorsThere are wheels without appropriate wheel
sensors mounted (e.g. winter tires).Have the TPMS or Advanced TPMS* checked by an
authorized Mercedes-Benz Light Truck Center.
Have the wheel sensors installed by an authorized
Mercedes-Benz Light Truck Center.
Tire Pressure Monitor
Wheel Sensor MissingVehicles with Advanced TPMS*:
One or more sensors are defect (e.g.
battery is empty).
The respective tire is indicated by
---
instead of the tire inflation pressure in the
multifunction display.
Have the Advanced TPMS* checked by an autho-
rized Mercedes-Benz Light Truck Center.
Vehicles with Advanced TPMS*:
One or more wheels without appropriate
wheel sensors mounted (e.g. spare tire).
The respective tire is indicated by
---
instead of the tire inflation pressure in the
multifunction display.
Have the wheel sensors installed by an authorized
Mercedes-Benz Light Truck Center.
Tire Pressure Monitor
Currently UnavailableThe TPMS or Advanced TPMS* is unable to
monitor the tire pressure due to a nearby
radio interference source.As soon as the causes of the malfunction have been
removed, the TPMS or Advanced TPMS* automati-
cally becomes active again after a few minutes
driving.

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.