2011 MERCEDES-BENZ G-CLASS check engine light

ProblemPossible 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.XOnly depress the accelerator pedal slightly.XHave the cause rectified immediately at a qualified specialist
workshop, e.g. an authorized Mercedes-Benz Center.
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.XStop as soon as possible and allow the engine and the coolant
to cool down.XCheck the coolant level ( Y page 217). Observe the warning
notes as you do so and add coolant if necessary.Automatic transmission
Important safety notes
GWarning
It is dangerous to shift AUTOTRONIC 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.
GWarning
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.
GWarning!
Keep in mind that turning off the engine alone
only will shift AUTOTRONIC into neutral
position N automatically.
Always shift AUTOTRONIC 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 transmission121Driving and parkingZProCarManuals.com

! Do not use diesel to refuel vehicles with a
gasoline engine. Even small amounts of the
wrong fuel result in damage to the fuel
system and engine.
! Do not switch on the ignition if you
accidentally refuel with the wrong fuel.
Otherwise, the fuel will enter the fuel lines.
Notify a qualified specialist workshop and
have the fuel tank and fuel lines drained
completely.
Gasoline
Fuel grade
! You should only refuel with unleaded
premium-grade gasoline as this avoids
damaging the catalytic converter.
If engine running problems are apparent,
have the cause checked immediately and
repaired. Excess unburned fuel can
otherwise enter the catalytic converter,
leading to overheating and possibly
causing a fire.
i Only refuel with unleaded premium-grade
gasoline with a specified minimum octane
number of 91 (average value of 96 RON/
86 MON).
Usually, you will find information about the
fuel grade on the pump. If you cannot find
the label on the gasoline pump, ask the gas
station staff.
You can find further information under
"Fuel" ( Y page 277), by consulting an
authorized Mercedes-Benz Center or
visiting http://www.mbusa.com (USA
only).
! Use a filter when refueling from a fuel can.
Otherwise, the fuel lines and/or injection
system could be blocked by particles from
the fuel can.
Refueling
Fuel filler flap
When you open or close the vehicle with the
key, the fuel filler flap is automatically
unlocked or locked.
The position of the fuel filler cap is displayed
in the instrument cluster 8. The arrow
next to the filling pump indicates the side of
the vehicle. The fuel filler flap is located to the
rear on the right.
Fuel filler cap G 550 (example)
:To open the fuel filler flap;Tire pressure table=Fuel type?To insert the fuel filler cap
Opening
XSwitch off the engine.
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) engine diagnostics
warning lamp may light up.
For further information on warning and
indicator lamps in the instrument cluster,
see ( Y page 188).
XRemove the key from the ignition lock.XPress the fuel filler flap in the direction of
arrow :.
The fuel filler flap opens slightly.XOpen the fuel filler flap.132RefuelingDriving and parking
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pedals. You could then no longer brake or
accelerate. This could lead to accidents and
injury.
Rolling with the engine switched offGWarning!
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
GWarning
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 Service Booklet.
Brakes
Important safety notesGWarning!
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
GWarning
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.
Driving tips137Driving and parkingZProCarManuals.com

Wet road surfaceGWarning
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.
GWarning
Make sure that you do not endanger other
road users when you apply the brakes.
Limited braking performance on salt
treated roads
GWarning
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.
Brake maintenance
! 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. This work should be carried
out at an authorized Mercedes-Benz
Center.
All checks and maintenance work on the
brake system must be carried out at a
qualified specialist workshop only. Consult an
authorized Mercedes-Benz Center for this
purpose.
Have the brake pads and the brake fluid
replaced at a qualified specialist workshop,
e.g. an authorized Mercedes-Benz Center.
GWarning
If other than recommended brake pads are
installed, or other than recommended brake
fluid is 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.
! A function or performance test may only
be carried out on a two-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,
the drive train or the brake system may
suffer damage.
! As the ESP ®
system operates
automatically, the engine and the ignition
must be switched off (the key 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).
138Driving tipsDriving and parking
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RCheck the depth of water before fording
rivers and streams.
R When fording, do not stop and do not
switch off the engine.
R Look out for obstacles such as rocks, holes,
tree stumps and furrows.
R Always keep the doors, rear door, windows
and the sliding sunroof closed while the
vehicle is in motion.
R Switch off cruise control.
R Do not stray from marked routes or paths.
R Adapt your speed to the terrain. The
rougher, steeper or more ruts on the
terrain, the slower your speed should be.
R Drive slowly and at an even speed through
the water. Ensure that a bow wave does not
form as you drive.
R On sand, drive quickly to overcome the
rolling resistance. Otherwise, the vehicle
could dig itself into the sand.
R Do not jump with the vehicle as this will
interrupt the vehicle's propulsion.
R Avoid high engine speeds. Drive at
reasonable 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.HEnvironmental note
Protection of the environment is of primary
importance. Treat nature with respect.
Observe all prohibiting signs.
Checklist before driving off-road
XEngine oil level: check the engine oil and
top it up 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.XWheel-changing tool kit: check that the
jack is working and make sure you have the
wheelbrace, a robust tow cable and a
folding spade in the vehicle.XWheels and tires: check the tire tread
depth and tire pressure.XCheck for damage and remove any foreign
objects, e.g. small stones, from the
wheels/tires.XReplace any missing valve caps.XReplace dented or damaged wheels.XCarry a sound spare wheel.
Checklist after driving off-road
GWarning
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possible
damage to your vehicle has occurred, you
should turn on the hazard warning flashers,
carefully slow down, and drive with caution to
an area which is a safe distance from the road.
Inspect the tires and the vehicle underbody
for possible damage. If the vehicle appears
unsafe, have the vehicle towed to the nearest
authorized Mercedes-Benz Center or tire
dealer for repairs.
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.
XShift the transfer case to HIGH
( Y page 126).XDisengage the differential locks
( Y page 129).Driving tips143Driving and parkingZProCarManuals.com

XClean the headlamps and rear lights and
check for damage.XClean the front and rear license plates.XClean the wheels and tires with a water jet
and remove any foreign objects.XClean the wheels, tires, wheel arches and
the vehicle underside with a water jet;
check for any foreign objects and damage.XCheck 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.XAfter the trip, examine without fail the
entire undercarriage, wheels, tires, brakes,
bodywork structure, steering, chassis and
exhaust system for damage.XAfter driving for extended periods across
sand, mud, gravel, water or in similarly dirty
conditions, have the brake discs, wheels,
brake pads/linings and axle joints checked
and cleaned.XIf you detect strong vibrations after off-road
driving, check for foreign objects in the
wheels and drivetrain and remove any that
you find. Foreign objects can disturb the
balance and cause vibrations.XTest the brakes.
Driving on sand
GWarning!
Do not reduce the tire inflation pressure
before driving through sand. However, if you
do so, remember to correct the tire inflation
pressure before continuing your trip. Driving
with reduced tire inflation pressure increases
the risk of losing control of the vehicle and
rolling over.
Observe the following rules when driving on
sand:
R shift the transfer case to
LOW (Y page 126).
R avoid high engine speeds.
R limit the shift range of the automatic
transmission according to the off-road
conditions.
R drive quickly to overcome the rolling
resistance. Otherwise, the vehicle could dig
itself into the sand.
R drive in the tracks of other vehicles if
possible. Make sure that the ruts are not
too deep, that the sand is firm enough and
that your vehicle has sufficient ground
clearance.
Tire ruts and gravel roads
Observe the following rules when driving
along ruts in off-road terrain or on roads with
loose gravel:
! Check that the ruts are not too deep and
that your vehicle has sufficient clearance.
Otherwise, your vehicle could be damaged
or bottom out and get stuck.
R shift the transfer case to
LOW (Y page 126).
R avoid high engine speeds.
R observe the safety notes (Y page 142) and
the general notes (Y page 142) on off-road
driving.
R restrict the shift range of the automatic
transmission to 1 (Y page 123).
R drive slowly.
R where ruts are too deep, drive with the
wheels of one side on the center grassy
area, if possible.
144Driving tipsDriving and parking
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RAvoid high engine speeds – drive at
appropriate engine speeds (no more than
3000 rpm).
R Use the braking power of the engine when
driving down a slope. Observe the engine
speed, do not overrev the engine.
i Further information on the maximum
engine speed can be found in the
"Tachometer" and "Technical Data"
sections.
R Select a shift range appropriate to the
gradient.
R Before tackling steep downhill gradients,
select shift range 1 (Y page 123).
R Check the brakes after driving off-road for
a long time.GWarning!
Never turn the vehicle around on steep
inclines. The vehicle might roll over. If the
vehicle cannot complete the attempted climb,
back it down in reverse gear.
i Hill start assist will aid you when pulling
away on a hill.
For more information, see "Hill start assist"
( Y page 118).
Maximum gradient-climbing capability
Do not drive at an angle on slopes, inclines or
gradients, but instead follow the direct line of
fall. The maximum gradient-climbing
capability of your vehicle is 80%, which
corresponds to an approach/departure angle
of 38°. Note that the vehicle's gradient-
climbing capability depends on the off-road
conditions.
Accelerate carefully and make sure that the
wheels do not spin when driving on steep
terrain.
i If the load on the front axle is reduced
when pulling away on a steep uphill slope,
the front wheels have a tendency to spin.
4ETS detects this and brakes the wheels
accordingly. The rear wheel torque is
increased, making it easier to drive off.
Brow of hill
When driving on an uphill gradient, reduce
pressure slightly on the accelerator
immediately before reaching the top of the hill
(do not shift the transmission to position N).
Use the vehicle's own impetus to drive over
the top of the hill.
This style of driving prevents:
R the vehicle from lifting off the ground on the
brow of a hill
R loss of traction
R the vehicle from traveling too quickly down
the other side
Driving downhill
R Before tackling steep downhill gradients,
select shift range 1 (Y page 123).
This way you use the engine's braking
effect to reduce the speed. If this is not
sufficient, brake gently. When doing so,
make sure that the vehicle is facing in the
direction of the line of fall.
R Observe the notes on driving in
mountainous terrain ( Y page 146).
R Drive slowly.
R Do not drive at an angle down steep
inclines. Steer into the line of fall and drive
with the front wheels aligned straight.
Otherwise, the vehicle could slip sideways,
tip and rollover.
R Check that the brakes are working normally
after a long downhill stretch.
i The special off-road ABS( Y page 56)
enables accurate, brief and repeated
locking of the front wheels, causing them
to dig into the loose ground. Note that when
the front wheels are fully braked, they slide
easily over the surface of the ground,
making it difficult to steer.
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Safety systemsProblemPossible causes/consequences and M Solutions!
The yellow ABS warning
lamp is lit while the
engine is running.GRisk of accident
ABS (Anti-lock Brake System) is deactivated due to a malfunction.
BAS (Brake Assist), ESP ®
(Electronic Stability Program), EBD
(Electronic Brake force Distribution) and 4ETS are also temporarily
unavailable.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XVisit a qualified specialist workshop.
If the ABS control unit is faulty, there is also a possibility that other
systems, such as the navigation system or the automatic
transmission, will not be available.
!
The yellow ABS warning
lamp is lit while the
engine is running.GRisk of accident
The on-board voltage is too low. ABS has been deactivated due to
undervoltage.
ESP ®
, BAS, EBD and 4ETS are also therefore deactivated.
The brake system continues to function normally, but without the
functions listed above. The wheels could therefore lock if you
brake hard, for example.
XObserve the additional display messages in the multifunction
display.XDrive on carefully.XSwitch off consumers that are not required, e.g. the rear window
defroster or interior lighting.
ABS will be available again as soon as the vehicle's on-board
electrical system voltage increases.
If the warning lamp is still on:
XHave the battery and alternator checked at a qualified specialist
workshop.!
The yellow ABS warning
lamp is lit while the
engine is running.You have engaged the differential locks. ABS, BAS, EBD, ESP ®
and
4ETS have been deactivated.XDisengage the differential locks.
ABS, BAS, EBD, ESP ®
and 4ETS are subsequently reactivated.Warning and indicator lamps in the instrument cluster185On-board computer and displaysZProCarManuals.com