MERCEDES-BENZ R320CDI 2007 R171 Owner's Manual

450 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 missingOne or more sensors are defect (e.g.
battery is empty).
One or more wheels without appropriate
wheel sensors mounted (e.g. spare tire).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.
Vehicles with Advanced TPMS*:
The tire pressure for the respective tire is shown in
the multifunction display.
Tire pressure monitor
currently unavailableThe TPMS or Advanced TPMS* is unable to
monitor the tire pressure due to

a nearby radio interference source.

excessive wheel sensor temperatures.
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.

451 Practical hints
What to do if …
Symbol messages
Display symbolDisplay messagePossible cause/consequencePossible solution
#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 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.

452 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 66).
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.

453 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
;(USA only)
!(Canada only)
Release
parking brakeYou are driving with the parking
brake set.Release the parking brake (page 57).
;(USA only)
3(Canada only)
EBV, ABS, ESP inoperative
See Operator’s ManualThe EBP, the ABS, and the ESP®
have switched off due to a mal-
function. The BAS is also
switched off.
The brake system is still func-
tional but without the EBP, the
ABS, and the ESP
® available.
Continue driving with added caution.
Wheels may lock during hard braking,
reducing steering capability.
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.

454 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
;(USA only)
3(Canada only)
Check
brake fluid levelThere is insufficient brake fluid
in the reservoir.Risk of accident! Carefully stop the vehi-
cle in a safe location or as soon as it is
safe to do so.
Apply the parking brake (page 66).
Contact an authorized Mercedes-Benz
Light Truck Center. Do not add brake flu-
id! This will not solve the problem.
Warning!G
Driving with the message Check brake
fluid level
displayed can result in an ac-
cident. Have your brake system checked im-
mediately. Do not add brake fluid before
checking the brake system. Overfilling the
brake fluid reservoir can result in spilling
brake fluid on hot engine parts and the
brake fluid catching fire. You could be
seriously burned.
!If you find that the brake fluid in the brake
fluid reservoir has fallen to the minimum mark or
below, have the brake system checked for brake
pad thickness and leaks.

455 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
•Coolant level
Stop car, switch engine
offThe coolant is too hot.
Among other possible causes
(the cooling fan could be
malfunctioning), the poly-V-belt
could be broken.Stop the vehicle in a safe location or
as soon as it is safe to do so.
Turn off the engine.
Apply the parking brake (page 66).
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:
Wait for the message to disappear
before restarting the engine.
Doing otherwise could result in seri-
ous engine damage that is not
covered by the Mercedes-Benz
Limited Warranty.
(Continued on next page)

456 Practical hints
What to do if …
During severe operation conditions and
stop-and-go city traffic, the coolant tem-
perature may rise close to 248°F (120°C).
Display symbolDisplay messagePossible cause/consequencePossible solution
Observe the coolant temperature in the
multifunction display (
page 166).
If the temperature rises again:
Contact an authorized
Mercedes-Benz Light Truck Center
immediately.
Warning!G
Driving when your engine is overheated can
cause some fluids which may have leaked
into the engine compartment to catch fire.
You could be seriously burned.
Steam from an overheated engine can cause
serious burns and can occur just by opening
the engine hood. Stay away from the engine
if you see or hear steam coming from it.
Turn off the engine, get out of the vehicle
and do not stand near the vehicle until the
engine has cooled down.
!The engine should not be operated with the
coolant temperature above 248°F (120°C).
Doing so may cause serious damage which is
not covered by the Mercedes-Benz Limited
Warranty.

457 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
B Top up coolant
See Oper. ManualThe coolant level is too low.Add coolant (page 370).
If you have to add coolant frequently,
have the cooling system checked by an
authorized Mercedes-Benz Light Truck
Center.
Warning!G
Do not spill antifreeze on hot engine parts.
Antifreeze contains ethylene glycol which
may burn if it comes into contact with hot
engine parts. You could be seriously burned.
!Do not ignore the low engine coolant level
warning. Extended driving with the message and
symbol displayed may cause serious engine
damage not covered by the Mercedes-Benz
Limited Warranty.
Do not drive without sufficient amount of coolant
in the cooling system. The engine will overheat,
causing major engine damage.

458 Practical hints
What to do if …
When the message Add 1 qt. engine oil
when next refueling
(Canada: 1 liter)
appears while the engine is running and at
operating temperature, the engine oil level
has dropped to approximately the mini-
mum level.
When this occurs, the warning will first
come on intermittently and then stay on if
the oil level drops further.Visually check for oil leaks. If no obvious oil
leaks are noted, drive to the nearest
service station where the engine oil should
be topped to the required level with an
approved oil specified in the Factory
Approved Service Products pamphlet.
Display symbolDisplay messagePossible cause/consequencePossible solution
NCheck eng. oil level
at next refuelingThe engine oil level is too low.Check the engine oil level (page 366).
USA only:
Add 1 qt. engine oil
at next refueling
Canada only:
Add 1 liter engine oil
at next refueling
The engine oil level is too low.Add engine oil (page 369) and check
the engine oil level (
page 366).
Engine oil level
cannot be measuredThe measuring system is
malfunctioning.Have the measuring system checked by
an authorized Mercedes-Benz Light Truck
Center.

459 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
NEngine oil level
Stop car, turn engine offThere is no oil in the engine.
There is a danger of engine
damage.Carefully bring the vehicle to a halt as
soon as it is safe to do so in a safe
location.
Turn off the engine.
Add engine oil (page 369) and check
the engine oil level (
page 366).
Engine oil level
Reduce oil levelYou have added too much
engine oil. There is a risk of
damaging the engine and/or the
catalytic converter (gasoline en-
gine) or the oxidation catalyst
(diesel engine).Have oil siphoned or drained off.
Observe all legal requirements with
respect to its disposal.
Engine oil level
Visit workshopThe engine oil has dropped to a
critical level.Check the engine oil level (page 366)
and add oil as required (
page 369).
If you must add engine oil frequently, have
the engine checked for possible leaks.
!The engine oil level warnings should not be
ignored. Extended driving with the symbol dis-
played could result inserious engine damage that is not covered by the
Mercedes-Benz Limited Warranty.