2015 MERCEDES-BENZ G-Class check engine light

Problems with the SmartKey
Problem
Possible causes/consequences and
M
MSolutions You cannot lock or
unlock the vehicle
using the SmartKey. The SmartKey battery is discharged or nearly discharged.
X Point the tip of the SmartKey at the driver's door handle from a
distance of approximately 1.5 ft (50 cm) and try to unlock or lock
the vehicle again.
If this does not work: X Check the SmartKey battery (Y page 70) and replace it if nec-
essary (Y page 70).
X Unlock (Y page 75) or lock (Y page 75) the vehicle using the
mechanical key. The SmartKey is faulty.
X Lock or unlock the vehicle using the mechanical key
(Y page 75).
X Have the SmartKey checked at a qualified specialist workshop. You have lost a Smart-
Key. X
Have the SmartKey deactivated at a qualified specialist work-
shop.
X Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. You have lost the
mechanical key. X
Report the loss immediately to the vehicle insurers.
X If necessary, have the locks changed as well. The engine cannot be
started using the
SmartKey. The SmartKey has been in position
0(Y page 133) for a consid-
erable time.
X Remove the SmartKey and reinsert it into the ignition lock.
X Start the engine. The on-board voltage is too low.
X Switch off non-essential consumers, e.g. seat heating or interior
lighting, and try to turn the SmartKey again.
If this does not work:
X Check the battery and charge it if necessary (Y page 295).
or
X Jump-start the vehicle (Y page 296).
or
X Consult a qualified specialist workshop. 72
SmartKeyOpening and closing

with your bare hands. If necessary, clean the
glass tube when cold with alcohol or spirit and
rub it off with a lint-free cloth.
Protect bulbs from moisture during opera-
tion. Do not allow bulbs to come into contact
with liquids.
Xenon bulbs
If your vehicle is equipped with Xenon bulbs,
you can recognize this by the following: the
cone of light from the Xenon bulbs moves
from the top to the bottom and back again
when you start the engine. For this to be
observed, the lights must be switched on
before starting the engine.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure that these function correctly at all times.
Have the headlamp setting checked regularly.
LED lamps
You can replace neither Xenon bulbs nor LED
bulbs. Have LED bulbs changed at a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly.
Before changing bulbs
Have the following bulbs replaced at a quali-
fied specialist workshop:
R Additional turn signals in the exterior mir-
rors
R High-mounted brake lamp
R High-beam/low-beam headlamps (Xenon
bulbs)
R Daytime running lamps
R Parking lamps/standing lamps
R License plate lamp
i Individual segments of the license plate
lamp LEDs may fail without a display mes-
sage appearing in the multifunction dis-
play. Regularly check the license plate
lamp. If necessary, visit a qualified special-
ist workshop. You can replace the following bulbs:
R Fog lamp/cornering light with fog lamp
function
R Turn signal lamp (front)
R Brake/tail lamp
R Turn signal lamp (rear)
R Tail lamps/standing lamps
R Backup lamp
R Rear Fog Lamp
R Side marker lamps
Other bulbs
There are bulbs other than the Xenon bulbs
that you cannot replace yourself. Only replace the bulbs listed (Y page 109). Have the bulbs
that you cannot replace yourself replaced at a
qualified specialist workshop.
If you require assistance replacing bulbs, con-
sult a qualified specialist workshop.
Do not touch the glass tube of new bulbs with
your bare hands. Even minor contamination
can burn into the glass surface and reduce
the service life of the bulbs. Always use a lint- free cloth or only touch the base of the bulb
when installing.
Only use bulbs of the correct type.
If the new bulb still does not light up, consult a qualified specialist workshop.
Bulbs and lamps are an important aspect of
vehicle safety. You must therefore make sure
that these function correctly at all times.
Have the headlamp setting checked regularly. Overview: changing bulbs/bulb types
Front bulbs You can replace the following bulbs. The bulb
type can be found in the legend. Replacing bulbs
109Lights and windshield wipers Z

Selector lever
j
Park position
k Reverse gear
i Neutral
h Drive
When you select a transmission position, the
selector lever subsequently returns to its
original position.
The current transmission position P,R, Nor D
appears in the transmission position display
in the multifunction display.
Transmission position and drive pro-
gram display !
If the transmission position display in the
multifunction display is not working, you
should pull away carefully to check whether the desired transmission position is
engaged. Select transmission position D.
Do not restrict the shift range. :
Transmission position
; Drive program
Current transmission position :and current
drive program ;appear in the multifunction
display. The current position of the selector lever is
shown by the indicators next to the selector
lever.
The indicators light up when the SmartKey is
inserted into the ignition lock. The indicators go out when the SmartKey is removed from
the ignition lock.
When the selector lever is in position D, you
can influence the gearshifts made by the
automatic transmission by:
R restricting the shift range
R changing gear yourself
Engaging park position P X
When the vehicle is stationary, depress the
brake pedal and keep it depressed.
X Press the Pbutton in the center console.
i If you depress the brake pedal and push
the selector lever forwards or back to the
first point of resistance, park position Pis
disengaged. The transmission shifts to neu- tral N.
Park position Pis automatically engaged:
R if you remove the SmartKey from the igni-
tion lock
R if you open the driver's door while traveling
at low speed in transmission position Dor
R
R if DISTRONIC PLUS (Y page 169) brakes
your vehicle until it is stationary and at least one of the following conditions is fulfilled:
- the engine is switched off.
- the driver's door is open and the seat belt
is not fastened.
- there is a system malfunction.
- the power supply is insufficient.
Engaging reverse gear R !
Only shift the automatic transmission to
R
when the vehicle is stationary. 140
Automatic transmissionDriving and parking

a qualified specialist workshop and have
the fuel tank and fuel lines drained com-
pletely.
! Overfilling the fuel tank could damage the
fuel system.
! Take care not to spill any fuel on painted
surfaces. You could otherwise damage the
paintwork.
! 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.
If you overfill the fuel tank, pressure may build up in the fuel tank. This could cause fuel to
spray out when the fuel pump nozzle is
removed. There is a risk of injury. The fuel
tank is full when the fuel pump nozzle first
switches off. End the refueling process.
For further information on fuel and fuel quality
(Y page 337). Refueling
Vehicles with a fuel filler flap Example: G 550 fuel filler cap
:
To open the fuel filler flap
; Tire pressure table
= Fuel type
? To insert the fuel filler cap
When you open or close the vehicle with the
SmartKey, the fuel filler flap is automatically
unlocked or locked. The position of the fuel filler cap is displayed
8 in the instrument cluster. 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.
Opening the fuel filler cap :
To open the fuel filler flap
; Tire pressure table
= Fuel type
? To insert the fuel filler cap
X Switch the engine off.
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 warn-
ing lamp may light up.
Further information about warning and indi-
cator lamps in the instrument cluster can
be found in the Digital Operator's Manual.
X Remove the SmartKey from the ignition
lock.
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 ?.
Refueling X
Completely insert the filler neck of the fuel
pump nozzle into the tank and refuel.
i Do not add any more fuel after the pump
stops filling for the first time. Otherwise,
fuel may leak out. 148
RefuelingDriving and parking

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 sur-
face. This could cause damage to the drive train. This type of damage is not covered bythe Mercedes-Benz warranty.
Heavy and light loads G
WARNING
If you rest your foot on the brake pedal while
driving, the braking system can overheat. This increases the stopping distance and can even
cause the braking system to fail. There is a
risk of an accident.
Never use the brake pedal as a footrest. Never
depress the brake pedal and the accelerator
pedal at the same time.
! Depressing the brake pedal constantly
results in excessive and premature wear to
the brake pads.
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 air- flow to cool the brakes more quickly.
Wet roads If driving in heavy rain for a prolonged period
of time without braking, there may be a
delayed reaction from the brakes when brak-
ing for the first time. This may also occur after
the vehicle has been washed.
You have to depress the brake pedal more
firmly. Maintain a greater distance from the
vehicle in front.
After driving on a wet road or having the vehi-
cle washed, brake firmly while paying atten-
tion to the traffic conditions. This will warm up
the brake discs, thereby drying them more
quickly and protecting them against corro-
sion. Limited braking performance on salt-
treated roads If you drive on salted roads, a layer of salt
residue may form on the brake discs and
brake pads. This can result in a significantly
longer braking distance.
R Brake occasionally to remove any possible
salt residue. Make sure that you do not
endanger other road users when doing so.
R Carefully depress the brake pedal and the
beginning and end of a journey.
R Maintain a greater distance to the vehicle
ahead.
Servicing 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 mes-
sages in the multifunction display.
The brake fluid level may be too low due tobrake pad wear or leaking brake lines.
Have the brake system checked immedi-
ately. This work should be carried out at a
qualified specialist workshop.
! A function or performance test should
only be carried out on a 2-axle dynamom-
eter. 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 automati-
cally, the engine and the ignition must be
switched off (the SmartKey must be in posi-
tion 0or 1in the ignition lock) if the parking
brake is tested on a brake dynamometer
(for a maximum of ten seconds).
Braking applications triggered automati-
cally by ESP ®
may otherwise seriously dam-
age the brake system. 154
Driving tipsDriving and parking

R
Ensure that the wheels are in contact with
the ground at all times.
R Drive with extreme care on unfamiliar off-
road routes where visibility is poor. For
safety reasons, get out of the vehicle first
and survey the off-road route.
R Check 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, side win-
dows 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 ter-
rain, 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 roll-
ing resistance. Otherwise the vehicle's
wheels could become stuck in loose
ground.
R Do not jump with the vehicle as this will
interrupt the vehicle's propulsion.
R Avoid high engine speeds. Drive at appro-
priate engine speeds (maximum
3,000 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 qualified
specialist workshop.
i Do not use the HOLD function when driv-
ing off-road, on steep uphill or downhill gra- dients or on slippery or loose surfaces. The
HOLD function cannot hold the vehicle on
such surfaces. Checklist before driving off-road !
If the engine oil warning lamp lights up
while the vehicle is in motion, stop the vehi- cle 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 Oil level: check the engine oil level and add
oil if necessary.
Only then does the engine receive enough
oil when the vehicle is on a steep incline.
X Tire-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 Driving over rough terrain places greater
demands on your vehicle than driving on nor-
mal 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
RANGE(Y page 186).
X Disengage the differential locks
(Y page 190).
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. Driving
tips
159Driving an d parking Z

Hilltops
When driving on an uphill gradient, reduce
pressure slightly on the accelerator immedi-
ately 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(Ypage 145).
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 mountain-
ous terrain (Y page 161).
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. Oth-erwise, the vehicle could slip sideways, tip
and roll over.
R Check that the brakes are working normally
after a long downhill stretch.
i The special off-road ABS setting
(Y page 62) enables repeated, brief, pre-
cise locking of the front wheels, which
leads to the wheels digging 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. Driving systems
Cruise control
Important safety notes G
WARNING
The brake pedal moves when cruise control
brakes the vehicle. A foot in the area under
the brake pedal could become trapped. The
movement of the pedal, and therefore the
vehicle's ability to brake, may be restricted by objects in the area under the brake. There is a
risk of an accident and injury.
Do not place your foot under the brake pedal. Keep the area under the brake pedal free from
obstructions.
If you fail to adapt your driving style, cruise
control can neither reduce the risk of acci-
dent nor override the laws of physics. Cruise
control cannot take account of road, weather and traffic conditions. Cruise control is only
an aid. You are responsible for the distance to
the vehicle in front, for vehicle speed and for braking in good time. Adjust your driving style to the traffic conditions. Only engage cruise
control when the current road, weather and
traffic conditions permit it to be done safely.
Drive carefully and maintain a suitable dis-
tance to the vehicle in front.
Do not use cruise control:
R in traffic conditions that do not allow you to
drive at a constant speed, e.g. heavy traffic,
on winding roads or off-road
R on slippery road surfaces. Braking or accel-
erating could cause the drive wheels to lose
traction and the vehicle could then skid
R when there is poor visibility, e.g. due to fog,
heavy rain or snow
General notes Cruise control maintains a constant road
speed for you. On long and steep downhill
gradients, especially if the vehicle is laden,
you must select shift range
1,2or 3in good
time. By doing so, you will make use of the 162
Driving systemsDriving and parking

General notes
SPEEDTRONIC brakes automatically so that
you do not exceed the set speed. On long and steep downhill gradients, especially if the
vehicle is laden or towing a trailer, you must
select shift range 1,2or 3in good time. By
doing so, you will make use of the braking
effect of the engine, which relieves the load
on the brake system and prevents the brakes from overheating and wearing too quickly. If
you need additional braking, depress the
brake pedal repeatedly rather than continu-
ously.
i The speed indicated in the speedometer
may differ slightly from the limit speed
stored.
Cruise control lever :
To store the current speed or a higher
speed
; LIM indicator lamp
= To call up the last speed stored
? To store the current speed or a lower
speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate variable SPEEDTRONIC
You can operate cruise control and variable
SPEEDTRONIC with the cruise control lever. The LIM indicator lamp on the cruise control
lever indicates which system you have selec-
ted:
R LIM indicator lamp off: cruise control is
selected.
R LIM indicator lamp on: variable SPEED-
TRONIC is selected.
You can use the cruise control lever to limit
the speed to any speed above 30 km/h while
the engine is running.
Selecting variable SPEEDTRONIC :
To activate or increase speed
; LIM indicator lamp
= To activate at the current speed/last
stored speed
? To activate or reduce speed
A To switch between cruise control and var-
iable SPEEDTRONIC
B To deactivate cruise control
If you fail to adapt your driving style, SPEED-
TRONIC can neither reduce the risk of acci-
dent nor override the laws of physics. SPEED-
TRONIC cannot take account of road, weather
and traffic conditions. SPEEDTRONIC is only
an aid. You are responsible for the distance to the vehicle in front, for vehicle speed, for
braking in good time and for staying in lane.
Only engage SPEEDTRONIC when the current
road, weather and traffic conditions permit it to be done safely. Drive carefully and main-
tain a suitable distance to the vehicle in front.
X Check whether LIM indicator lamp ;is on. Driving systems
167Driving and parking Z