2007 MERCEDES-BENZ R320CDI check engine light

424 Practical hints
What to do if …
ProblemPossible cause/conse-
quenceSuggested solution
?(USA only)
±(Canada only)
The yellow engine malfunction
indicator lamp comes on while
driving.A loss of pressure has been
detected in the fuel system.
The fuel cap may not be closed
properly or the fuel system
may be leaky.Check the fuel cap (page 360).
If it is not closed properly:
Close the fuel cap.
If it is closed properly:
Have the fuel system checked by an
authorized Mercedes-Benz Light Truck
Center.
Your fuel tank is empty.After refueling start, turn off and
restart the engine three or four times in
succession.
The limp-home mode is canceled. You do
not need to have your vehicle checked.

425 Practical hints
What to do if …
ProblemPossible cause/consequenceSuggested solution
vThe yellow ESP® warning lamp
comes on while the engine is
running.The ESP® has been switched of with the ESP®
switch or has switched off due to a
malfunction.
Risk of accident!
Adapt your speed and driving to the prevail-
ing road, weather, and traffic conditions.Switch the ESP® back on
(
page 105).
If the ESP
® cannot be switched back on:
Continue driving with added caution.
Observe additional messages in the
multifunction display that may
appear.
Have the system checked at an autho-
rized Mercedes-Benz Light Truck
Center as soon as possible.
vThe yellow ESP® warning lamp
flashes while driving.The ESP® or traction control has come into
operation because of detected traction loss
of at least one tire.When driving off, apply as little throt-
tle as possible.
While driving, ease up on the acceler-
ator.
Adapt your speed and driving to the
prevailing road and weather condi-
tions.
Do not deactivate the ESP®.
Exceptions: (
page 104)
Failure to follow these instructions
increases the risk of an accident.

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.

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)

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.

507 Practical hints
Battery
!The battery is a valve-regulated lead acid
(VRLA) battery, also referred to as “fleece”
battery. Such batteries do not require topping-up
of the electrolyte level. VRLA batteries therefore
do not have cell caps and the battery cover is
non-removable. Do not attempt to open the
battery as otherwise the battery will be dam-
aged.
Even though VRLA batteries do not require
topping-up of the electrolyte level and cannot be
opened to check the electrolyte level, the
battery condition must be checked periodically
by performing a battery conductance test. Refer
to Maintenance Booklet for battery condition
testing intervals.
As with any other battery, the battery may
discharge if the vehicle is not operated for an
extended period of time. You can connect a
battery maintenance charge unit tested and
approved for use on your vehicle model or dis-
connected the battery to prevent battery dis-
charge. Contact an authorized Mercedes-Benz
Light Truck Center for more information.!The factory-equipped VRLA battery is
leak-proofed. Only use a battery as replacement
that has the same security features and is of
identical size, voltage, and capacity as the
factory-equipped battery.
The battery, the battery ventilation and the later-
al plug must always be securely installed when
the vehicle is in operation.
Warning!G
Jump starting must only be done using the
jump-start contacts located in the engine
compartment (
page 514).
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 506).
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.