2012 MERCEDES-BENZ G-Class check engine light

otherwise fog up as, in air-recirculation
mode,
no
fresh air is drawn into the vehicle.
R Use the residual heat function if you want
to heat or ventilate the vehicle interior
when the ignition is switched off. The
"residual heat" function can only be
activated or deactivated with the ignition
switched off.
R At very low temperatures, the rear window
defroster is only switched on once the
vehicle interior has warmed up. Activating/deactivating climate
control
Important information G
WARNING
When the climate control system is
deactivated, the outside air supply and
circulation are also deactivated. Only choose
this setting for a short time. Otherwise the
windows could

fog up, impairing visibility and
endangering you and others.
i Switch on climate control primarily using
the à button ( Y page 107).
Activating/deactivating X
Turn the SmartKey to position 2 in the
ignition lock.
X To switch on:
turn
control : clockwise to
the desired position (except position 0)
(Y page 105).
X The previously selected settings come into
effect again.
X To switch off: turn control : counter-
clockwise to position 0(Y page 105). Activating/deactivating the cooling
with air dehumidification function
Important information The cooling with air dehumidification function
is only available when the engine is running.
The air inside the vehicle is cooled and
dehumidified according to the temperature
selected.
G
WARNING
If you switch off the cooling function, the
vehicle will not be cooled when weather
conditions are

warm. The windows can fog up
more quickly. Window fogging may impair
visibility and endanger you and others.
Condensation may drip from the underside of
the vehicle when it is in cooling mode. This is
normal and not a sign that there is a
malfunction.
i The cooling with air dehumidification
function uses refrigerant R134a. This
coolant does not contain
chlorofluorocarbons, and therefore does
not damage the ozone layer.
Activating/deactivating !
If the cooling with air dehumidification
does not switch on, it is possible that the
climate control system has lost coolant.
Have the cooling with air dehumidification
checked at

a qualified specialist workshop.
X To activate: press the Á button.
The indicator

lamp in the Á button lights
up.
X To switch off: press the Á button.
The indicator

lamp in the Á button goes
out. The cooling with air dehumidification
function has a delayed switch-off feature. 106
Operating the climate control system
Climate control

on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal.
! Warm up the engine quickly. Do not use
the engine's full performance until it has
reached operating temperature.
Only shift the automatic transmission to
the desired
drive position when the vehicle
is stationary.
Where possible, avoid spinning the drive
wheels when pulling away on slippery
roads. You could otherwise damage the
drive train.
! Avoid high engine speeds when the
engine is cold. The engine's service life
could otherwise be significantly shortened.
Do not use the engine's full performance
until it has reached operating temperature. SmartKey positions
g
To remove the SmartKey
1 Power supply for some consumers, such
as the windshield wipers
2 Ignition (power supply for all consumers)
and drive position
3 To start the engine i
You can only remove the SmartKey if:
R the SmartKey is in position
0 in the
ignition lock.
R the automatic transmission selector
lever is in P.
As soon

as the ignition is switched on, all the
indicator lamps in the instrument cluster light
up. If an indicator lamp does not go out after
the engine is started or if it lights up while the
vehicle is in motion, see ( Y page 180).
If the SmartKey is in position 0 in the ignition
lock for an extended period of time, it can no
longer be turned in the ignition lock. The
steering is then locked. To unlock, remove the
SmartKey and reinsert it into the ignition lock.
The steering is locked when you remove the
SmartKey from the ignition lock.
X Remove the SmartKey when the engine is
switched off.
The starter battery could otherwise be
discharged.
If you cannot turn the SmartKey in the ignition
lock, the starter battery may not be charged
sufficiently.
X Check the starter battery and charge if
necessary ( Y page 231).
or
X Jump-start the vehicle (Y page 233). Starting the engine
Important safety notes G
WARNING
Inhalation
of exhaust gas is hazardous to your
health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause
unconsciousness and possible death.
Do not

run the engine in confined areas (such
as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are
entering the vehicle while driving, have the
cause determined and corrected
immediately. If you must drive under these Driving
115
Driving and parking
Z

Problem Possible causes/consequences and
M SolutionsThe engine is not
running smoothly and
is misfiring. There is a malfunction in the engine electronics or a mechanical
component of the engine management system.
X
Only depress the accelerator pedal slightly.
X Have the cause rectified immediately at a qualified specialist
workshop.
Otherwise, non-combusted fuel may get into the catalytic
converter and damage it. The coolant
temperature gauge
shows a value above
248 ‡
(120 †).
Additionally, a display
message
may appear in
the multifunction
display and a warning
tone may sound. The coolant level is too low. The coolant is too hot and the engine
is no longer being cooled sufficiently.
X
Stop as soon as possible and allow the engine and the coolant
to cool down.
X Check the coolant level (Y page 213). Observe the warning
notes as you do so and add coolant if necessary. Automatic transmission
Important safety notes
G
WARNING
It is dangerous to shift the automatic
transmission out of parking position P or
neutral position N if the engine speed is
higher than

idle speed. If your foot is not firmly
on the brake pedal, the vehicle could
accelerate quickly forward or in reverse. You
could lose control of the vehicle and hit
someone or something. Only shift into gear
when the engine is idling normally and when
your right foot is firmly on the brake pedal. G
WARNING
On slippery road surfaces, never downshift in
order to obtain braking action. This could
result in

drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of loss of control. G
WARNING
Keep in mind that turning off the engine alone
only will

shift the automatic transmission into
neutral position N automatically.
Always shift the automatic transmission into
park position P before turning off the engine.
Otherwise the vehicle could roll away which
could result in an accident and/or serious
personal injury.
i Bear in mind that the power transmission
between the engine and the transmission
is interrupted when the engine is switched
off. Therefore, to prevent the vehicle from
rolling away, shift the automatic
transmission to position P and apply the
parking brake when the engine is switched
off and the vehicle is stationary. Automatic transmission
119
Driving and parking Z

i
When the engine is running and the fuel
filler flap is open, the yellow reserve fuel
warning lamp and the = (USA only)
or ; (Canada only) Check Engine
warning lamp may light up.
For further information on warning and
indicator lamps in the instrument cluster,
see ( Y page 184).
X Remove the SmartKey from the ignition
lock.
X Press the fuel filler flap in the direction of
arrow :.
The fuel filler flap opens slightly.
X Open the fuel filler flap.
X Turn the fuel filler cap counterclockwise
and remove it.
X Insert the fuel filler cap into the holder
bracket on the inside of filler flap ?.
X Completely insert the fuel pump nozzle into
the filler neck and refuel.
X Only fill the tank until the pump nozzle
switches off.
! Overfilling the
fuel tank could damage the
fuel system.
Closing X
Replace the fuel filler cap and turn it
clockwise. The fuel filler cap audibly
engages.
X Close the fuel filler flap.
i Close the

fuel filler flap before locking the
vehicle. A locking pin otherwise prevents
the fuel filler flap from closing after the
vehicle has been locked. Fuel filler flap emergency release
G
WARNING
Avoid contact with the vehicle walls as they
may contain sharp edges. Otherwise, you
could injure yourself while releasing the fuel
filler flap. The emergency release is located in the cargo
compartment, on the right-hand side when
viewed in the direction of travel, behind the
rear panel trim.
X
Open the rear door. X
Disconnect edge guard : on the door
pillar.
X Remove rear panel trim ;. X
Pull emergency release = in the direction
of the arrow.
The fuel filler flap is unlocked.
X Open the fuel filler flap.126
Refueling
Driving and parking

accelerate. This could lead to accidents and
injury.
Rolling with the engine switched off G
WARNING
There is no power assistance for the steering
and the

brake when the engine is not running.
Steering and braking requires significantly
more effort and you could lose control of the
vehicle and cause an accident as a result.
Do not turn off the engine while the vehicle is
in motion.
Exhaust check G
WARNING
Inhalation
of exhaust gas is hazardous to your
health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause
unconsciousness and possible death.
Do not

run the engine in confined areas (such
as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are
entering the vehicle while driving, have the
cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one
window fully open at all times.
Certain engine systems are designed to keep
the level of poisonous components in exhaust
fumes within legal limits.
These systems only work at peak efficiency
when they are maintained exactly in
accordance with the manufacturer's
specifications. For this reason, all work on the
engine must be carried out only by qualified
and authorized Mercedes-Benz technicians.
The engine settings must not be changed in
any circumstances. Furthermore, all specific
service work must be carried out at regular
intervals and in accordance with the
Mercedes-Benz service requirements. Details
can be found in the Maintenance Booklet. Brakes
Important safety notes G
WARNING
On
slippery road surfaces, never downshift in
order to obtain braking action. This could
result in

drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of control loss.
Do not engage the transfer case in position
LOW when driving on ice or packed snow. At
speeds below 18 mph (30 km/h) vehicle
steering is adversely affected by the Off-road
ABS.
Downhill gradients !
On long and steep gradients, you must
reduce the load on the brakes by shifting
early to

a lower gear. This allows you to take
advantage of the engine braking effect and
helps avoid overheating and excessive
wear of the brakes.
When you take advantage of the engine
braking effect, a drive wheel may not turn
for some time, e.g. on a slippery road
surface. This could cause damage to the
drive train. This type of damage is not
covered by the Mercedes-Benz warranty.
Heavy and light loads G
WARNING
Depressing
the brake pedal constantly results
in excessive

and premature wear to the brake
pads.
It may also cause the brakes to overheat,
seriously impairing their effectiveness. It may
then not be possible to stop the vehicle in
sufficient time to avoid an accident.
If the brakes have been subjected to a heavy
load, do not stop the vehicle immediately, but
drive on for a short while. This allows the
airflow to cool the brakes more quickly. 130
Driving tips
Driving and parking

Wet roads
G
WARNING
After driving in heavy rain for some time
without applying
the brakes or through water
deep enough to wet brake components, the
first braking action may be somewhat
reduced. You have to depress the brake pedal
more firmly. Maintain a safe distance from
vehicles in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion. G
WARNING
Make sure that you do not endanger other
road users when you apply the brakes.
Limited braking performance on salt-
treated roads G
WARNING
The layer of salt on the brake discs and the
brake pads/linings may cause a delay in the
braking effect, resulting in a significantly
longer braking distance, which could lead to
an accident.
To avoid this danger, you should:
R occasionally brake carefully, without
putting other road users at risk, when you
are driving on salted roads. This helps to
remove any salt that may have started to
build up on the brake discs and the brake
pads/linings.
R maintain a greater distance to the vehicle
ahead and drive with particular care.
R carefully apply the brakes at the end of a
trip and immediately after commencing a
new trip,

so that salt residues are removed
from the brake discs. Servicing the brakes G
WARNING
If brake pads or brake fluid other than those
recommended are used, the braking
properties of the vehicle can be degraded to
an extent that safe braking is substantially
impaired. This could result in an accident. G
WARNING
Make sure that you do not endanger other
road users when you apply the brakes.
! If the

brake warning lamp lights up in the
instrument cluster and you hear a warning
tone even though the parking brake has
been released, the brake fluid level may be
too low. Observe additional warning
messages in the multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked
immediately. Have this work carried out at
an authorized Mercedes-Benz Center.
! A function or performance test should
only be carried out on a 2-axle
dynamometer. If you are planning to have
the vehicle tested on such a dynamometer,
contact an authorized Mercedes-Benz
Center to obtain further information first.
Otherwise, you could damage the drive
train or the brake system.
! As the ESP ®
system operates
automatically, the engine and the ignition
must be switched off (the SmartKey must
be in position 0 or 1 in the ignition lock) if
the parking brake is tested on a brake
dynamometer (for a maximum of ten
seconds).
Braking applications triggered
automatically by ESP ®
may otherwise
seriously damage the brake system.
All checks and maintenance work on the
brake system must be carried out at a
qualified specialist workshop. Driving tips
131
Driving and parking Z

Winter driving
General notes G
WARNING
If the vehicle becomes trapped in snow,
ensure that snow is kept away from the
exhaust pipe and from around the vehicle as
long as the engine is running. Otherwise,
poisonous carbon monoxide (CO) may enter
the vehicle,
resulting in loss of consciousness
and even death.
To assure sufficient fresh air ventilation, open
a window slightly on the side of the vehicle
not facing the wind.
Have your vehicle winterproofed at a qualified
specialist workshop at the onset of winter.
Observe the notes in the "Winter operation"
section ( Y page 244).
Driving with summer tires Observe the notes in the "Winter operation"
section (
Y
page 244).
Slippery road surfaces G
WARNING
The outside temperature indicator is not
designed to serve as an ice-warning device
and is therefore unsuitable for that purpose.
Indicated temperatures just above the
freezing point

do not guarantee that the road
surface is free of ice. The road may still be icy,
especially in wooded areas or on bridges. G
WARNING
On
slippery road surfaces, never downshift in
order to obtain braking action. This could
result in

drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of control loss.
Do not engage the transfer case in position
LOW when driving on ice or packed snow. At
speeds below 18 mph (30 km/h) vehicle steering
is adversely affected by the Off-road
ABS.
Drive particularly carefully on slippery road
surfaces. Avoid

sudden acceleration, steering
and braking maneuvers. Do not use cruise
control.
If the vehicle threatens to skid or cannot be
stopped when moving at low speed:
X Shift the transmission to position N.
X Try to bring the vehicle under control using
corrective steering.
i For more information on driving with
snow chains, see ( Y page 245). G
WARNING
Make sure that you do not endanger other
road users when you apply the brakes. Off-road driving
Important safety notes G
WARNING
Grains of sand, particles of dirt and other
abrasive materials can enter the brake
system. This can lead to excessive wear and
unpredictable braking efficiency.
After the brakes have been exposed to dirty
conditions, have them checked and cleaned
at a

qualified specialist workshop. Otherwise,
there is a risk that braking power may be
insufficient in the event of an emergency, or
that the braking effect may be unpredictable. G
WARNING
Do
not load items on the basic carrier bars. It
may cause

instability during some maneuvers
which could result in an accident.
Drive slowly in unknown terrain. This will
make it easier to recognize unexpected
obstacles and avoid damage to the vehicle.
To help avoid the vehicle rolling over, never
turn it around on steep inclines. If the vehicle 134
Driving tips
Driving and parking

R
Avoid high engine speeds. Drive at
appropriate engine speeds (maximum
3000 rpm).
R Do not shift the automatic transmission to
transmission position N.
R Always check the vehicle for damage after
off-road driving.
i Information about retrofitting special all-
terrain tires is available from any
authorized Mercedes-Benz Center. H
Environmental note
Protection of the environment is of primary
importance. Treat nature with respect.
Observe all prohibiting signs.
Checklist before driving off-road X
Engine oil level: check the engine oil level
and add oil if necessary.
Only then does the engine receive enough
oil when the vehicle is standing on a steep
incline.
! If the engine oil warning lamp lights up
while the vehicle is in motion, stop the
vehicle in

a safe place as soon as possible.
Check the engine oil level. The engine oil
warning lamp warning must not be ignored.
Continuing the journey while the symbol is
displayed could lead to engine damage.
X Wheel-changing tool kit: check that the
jack is

working and make sure you have the
lug wrench, a robust tow cable and a folding
spade in the vehicle.
X Wheels and tires: check the tire tread
depth and tire pressure.
X Check for damage and remove any foreign
objects, e.g. small stones, from the
wheels/tires.
X Replace any missing valve caps.
X Replace dented or damaged wheels.
X Carry a sound spare wheel. Checklist after driving off-road G
WARNING
If you notice sudden significant vibrations or
unusual handling performance or if you
suspect that damage has occurred to the
vehicle, you should activate the hazard
warning lamps, gently reduce speed and
carefully head for an area that is located at a
safe distance from the road.
Check the tires and the underside of the
vehicle for damage. If the vehicle seems
unsafe, have the vehicle towed away to the
nearest Mercedes-Benz Center or tire dealer
to be repaired.
Driving over rough terrain places greater
demands on your vehicle than driving on
normal roads. After driving off-road, check
the vehicle.

This allows you to detect damage
promptly and reduce the risk of an accident
to yourself and other road users.
X Shift the transfer case to HIGH
(Y page 145).
X Disengage the differential locks
(Y page 148).
X Clean the headlamps and rear lights and
check for damage.
X Clean the front and rear license plates.
X Clean the wheels and tires with a water jet
and remove any foreign objects.
X Clean the wheels, tires, wheel arches and
the vehicle underside with a water jet;
check for

any foreign objects and damage.
X Check whether twigs or other parts of
plants have become trapped. These
increase the risk of fire and can damage
fuel pipes, brake hoses or the rubber
bellows of the axle joints and propeller
shafts.
X After the trip, examine without fail the
entire undercarriage,

wheels, tires, brakes,
bodywork structure, steering, chassis and
exhaust system for damage. 136
Driving tips
Driving and parking