engine light MERCEDES-BENZ ML320 2008 W164 Repair Manual

430 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! Stop the vehicle in a
safe location or as soon at is safe to do
so.
Apply the parking brake (page 65).
Contact an authorized Mercedes-Benz
Light Truck Center. Do not add brake
fluid! This will not solve the problem.
Warning!G
Driving with the message Check Brake
Fluid Level
displayed can result in an
accident. Have your brake system checked
immediately. 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.

431 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
Ï Coolant Level
Stop car, switch engine off.The 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 safe location or as
soon as it safe to do so.
Apply the parking brake (page 65).
Turn off the engine.
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:
Do not continue to drive the vehicle with
this message displayed. Doing so could
result in serious engine damage that is
not covered by the Mercedes-Benz Limit-
ed Warranty.
(Continued on next page)

432 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 154).
If the temperature raises 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 which can occur
just by opening the hood. Stay away
from the engine if you see or hear steam
coming from it.
Stop the vehicle in a safe location away from
other traffic. 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.

433 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
B Top Up Coolant
See Operator’s ManualThe coolant level is too low.Add coolant (page 345).
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.

434 Practical hints
What to do if …
When the message Check engine oil
level at next refueling.
appears while
the engine is running and at operating tem-
perature, the engine oil level has dropped
to approximately the minimum 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 engine oil.For information on approved engine oils,
refer to the Factory Approved Service
Products pamphlet (USA only) or contact
an authorized Mercedes-Benz Light Truck
Center.
Display symbolDisplay messagePossible cause/consequencePossible solution
NCheck engine oil level
at next refueling.The engine oil level is too low.Check the engine oil level (page 343)
and add engine oil as required
(
page 344).
!The engine oil level warning should not be
ignored. Extended driving with the symbol dis-
played could result in serious engine damage
that is not covered by the Mercedes-Benz
Limited Warranty.

437 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
FKey Detected
In VehicleA SmartKey with KEYLESS-GO*
left in the vehicle was detected
while trying to lock the vehicle
from the outside.Take the SmartKey with KEYLESS-GO*
out of the vehicle.
Remove KeyYou have forgotten to remove
the SmartKey.Remove the SmartKey from the starter
switch.
You need a new key.There is no additional code avail-
able for SmartKey or SmartKey
with KEYLESS-GO*.Contact an authorized Mercedes-Benz
Light Truck Center as soon as possible.
Key
Does Not Belong to VehicleThe SmartKey or SmartKey with
KEYLESS-GO* in the starter
switch does not belong to the
vehicle.Find the SmartKey or SmartKey with
KEYLESS-GO* that belongs to the
vehicle to operate the vehicle.
Change
Key BatteriesThe batteries in the SmartKey
with KEYLESS-GO* are dis-
charged.Replace the batteries (page 461).
Don’t Forget
Your KeyThis message appears for a
maximum of 60 seconds if the
driver’s door is opened with the
engine shut off and no SmartKey
in the starter switch.
This message is only a reminder.Insert the SmartKey in the starter
switch (
page 40).
or
Take the SmartKey with KEYLESS-GO*
with you when leaving the vehicle.

444 Practical hints
What to do if …
Display symbolDisplay messagePossible cause/consequencePossible solution
4Reserve FuelThe fuel level has gone below the reserve
mark.Refuel at the next gas station
(
page 337).
Ultra Low-sulfur
Diesel Fuel OnlyVehicles with diesel engine only:
The fuel level has gone below the reserve
mark.Refuel at the next gas station
(
page 337).
Only use commercially available
vehicular ULTRA-LOW SULFUR
HIGHWAY DIESEL FUEL
(15 ppm SULFUR MAXIMUM).
L Tele Aid
InoperativeOne or more main functions of the
Tele Aid system are malfunctioning.Have the Tele Aid system checked by
an authorized Mercedes-Benz Light
Truck Center.
Tele Aid
BatteryThe emergency power battery for the
Tele Aid system is malfunctioning. If the
vehicle battery is also malfunctioning or
drained, Tele Aid will not be operational.Have the Tele Aid system checked by
an authorized Mercedes-Benz Light
Truck Center.
tFunction
unavailableThis display appears if buttont
ors on the multifunction steering
wheel is pressed and the vehicle is not
equipped with a telephone.
W Top Up
Washer FluidThe fluid level has dropped to about 1/3 of
total reservoir capacity.Add washer fluid (page 346).

478 Practical hints
Flat tire
Preparing the vehicle
Vehicles with air suspension program*:
Make sure the vehicle level is set to
highway (
page 257).
Park the vehicle in a safe distance from
moving traffic on a hard, flat surface
when possible.
Turn on the hazard warning flasher
(
page 141).
Turn the steering wheel so that the
front wheels are in a straight-ahead
position.
Set the parking brake (page 57).
Set the automatic transmission to park
positionP (
page 185).
Turn off the engine (page 39).
Have any passenger exit the vehicle at
a safe distance from the roadway.
Vehicles with SmartKey: Remove the
SmartKey from the starter switch.
Vehicles with KEYLESS-GO*: Open the
driver’s door (this puts the starter
switch in position0, same as with the
SmartKey removed from the starter
switch). The driver’s door then can be
closed again.
Remove the KEYLESS-GO*
start/stop button from the starter
switch.
Warning!G
The dimensions of the spare wheel
(Minispare wheel or collapsible tire) are dif-
ferent from those of the road wheels. As a
result, the vehicle handling characteristics
change when driving with a spare wheel
mounted. Adapt your driving style accord-
ingly.
The spare wheel is for temporary use only.
When driving with a spare wheel mounted,
ensure proper tire pressure and do not ex-
ceed a vehicle speed of 50 mph (80 km/h).
Drive to the nearest Mercedes-Benz Light
Truck Center as soon as possible to have the
spare wheel replaced with a regular road
wheel.
Never operate the vehicle with more than
one spare wheel mounted.
Do not switch off the ESP
® when a
Minispare wheel is mounted.
Warning!G
Vehicles with air suspension program*:
Do not open or close any doors or the
tailgate while mounting a spare wheel. The
vehicle could rise or lower to a previously
selected level. You or others could be
injured as a result.
iOpen door only when conditions are safe to
do so.

480 Practical hints
Flat tire
Prevent the vehicle from rolling away
by blocking wheels with wheel chocks
or other sizeable objects.One collapsible wheel chock is includ-
ed with the vehicle tool kit
(
page 448). For information on set-
ting up the collapsible wheel chock,
see (
page 452).
Changing wheel on a level surface
Changing rear wheel on passenger side
(Example illustration)
Place the wheel chock in front of and
another sizeable object behind the
wheel that is diagonally opposite to the
wheel being changed.
Changing wheel on a slight decline
Always try lifting the vehicle using the jack
on a level surface. However, should
circumstances require you to do so on a
slight decline, place the wheel chock and
another sizeable object as follows:
Changing wheel on passenger side
(Example illustration)
Always firmly set parking brake and block
wheels with wheel chocks or other sizeable
objects before raising vehicle with jack. Do
not disengage parking brake while the vehi-
cle is raised.
Make sure that the ground on which the ve-
hicle is standing and where you place the
jack is solid, level and not slippery. If neces-
sary, use a large underlay. On slippery sur-
faces, such as tiled floors, you should use a
non-slip underlay, for example a rubber mat.
Do not use wooden blocks or similar objects
to support the jack. Otherwise the jack may
not be able to achieve its load-bearing ca-
pacity if it is not at its full height.
Never start the engine when the vehicle is
raised.
Also observe the notes on the jack.
Warning!G
Only jack up the vehicle on level ground or
on slight inclines/declines. Otherwise, the
vehicle could fall off the jack and injure you
or others.


488 Practical hints
Bleeding the fuel system (diesel engine only)
Driving the vehicle until the fuel tank is
empty is not recommended. Otherwise, air
may be sucked into the fuel system. If this
happens, the? malfunction indicator
lamp (USA only) or the± malfunction
indicator lamp (Canada only) comes on
and the engine may not start immediately
after refueling the vehicle.
After refueling:
Make sure the automatic transmission
is set toP.
The gear position indicator in the multi-
function display should be on
P.
Do not depress the accelerator.
Turn the SmartKey in the starter switch
to position 2 for at least 10 seconds
(
page 40).
Return the SmartKey in the starter
switch to position 0 (
page 40).
Turn the SmartKey in the starter switch
to position3 (
page 40) and hold it
there for a maximum of 40 seconds or
until the engine runs surge-free.
If the engine does not start:
Wait for approximately 2 minutes.
Turn the SmartKey in the starter switch
to position3 (
page 40) and hold it
there for a maximum of 40 seconds or
until the engine runs surge-free.
If the engine still does not start, do not
make any further attempts to start the
engine. Contact an authorized
Mercedes-Benz Light Truck Center or call
Roadside Assistance (
page 298).iVehicles with KEYLESS-GO*: If necessary,
remove the KEYLESS-GO start/stop button from
the starter switch (
page 40).iWhen the ?malfunction indicator lamp
(USA only) or the ±malfunction indicator
lamp (Canada only) has been illuminated for the
above condition, it will remain illuminated until
the engine was cycled on and off four times in a
row.