check engine light MERCEDES-BENZ M-Class 2015 W166 User Guide

Crash-responsive emergency lighting
The interior lighting is activated automatically
if the vehicle is involved in an accident.
X To switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or X Lock and then unlock the vehicle using the
SmartKey. Replacing bulbs
Important safety notes
G
DANGER
Xenon bulbs carry a high voltage. You can get an electric shock if you remove the cover of
the Xenon bulb and touch the electrical con-
tacts. There is a risk of fatal injury.
Never touch the parts or the electrical con-
tacts of the Xenon bulb. Always have work on
the Xenon bulbs carried out at a qualified spe-
cialist workshop.
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. G
WARNING
Bulbs, lamps and connectors can get very hot when operating. If you change a bulb, you
could burn yourself on these components.
There is a risk of injury.
Allow these components to cool down before changing a bulb.
Do not use a bulb that has been dropped or if
its glass tube has been scratched.
The bulb may explode if:
R you touch it
R it is hot R
you drop it
R you scratch it
Only operate bulbs in enclosed lamps
designed for that purpose. Only install spare
bulbs of the same type and the specified volt- age.
Marks on the glass tube reduce the service
life of the bulbs. Do not touch the glass tube
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.
There are bulbs other than the Xenon bulbs
that you cannot replace. Replace only the
bulbs listed (Y page 129). Have the bulbs that
you cannot replace yourself changed at a
qualified specialist workshop.
If you require assistance changing bulbs, con- sult a qualified specialist workshop.
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
You can change the following bulbs. The bulb type can be found in the legend. Replacing bulbs
129Lights and windshield wipers Z

Problems with the windshield wipers
Problem
Possible causes/consequences and
0050
0050Solutions The windshield wipers
are jammed. Leaves or snow, for example, may be obstructing the windshield
wiper movement. The wiper motor has been deactivated.
X For safety reasons, you should remove the SmartKey from the
ignition lock.
or X Switch off the engine using the Start/Stop button and open the
driver's door.
X Remove the cause of the obstruction.
X Switch the windshield wipers back on. The windshield wipers
fail completely. The windshield wiper drive is malfunctioning.
X Select another wiper speed on the combination switch.
X Have the windshield wipers checked at a qualified specialist
workshop. 136
Windshield wipersLights and windshield wipers

G
WARNING
Flammable materials introduced through
environmental influence or by animals can
ignite if in contact with the exhaust system or parts of the engine that heat up. There is a risk
of fire.
Carry out regular checks to make sure that
there are no flammable foreign materials in
the engine compartment or in the exhaust
system.
! Do not depress the accelerator when
starting the engine.
General notes i
Vehicles with a gasoline engine:
the
catalytic converter is preheated for up to
30 seconds after a cold start. The sound of the engine may change during this time.
Automatic transmission X
Shift the transmission to position P
(Y page 168).
The transmission position display in the
multifunction display shows
P (Y page 168).
i You can start the engine in transmission
position Pand N.
Starting procedure with the SmartKey X
To start a gasoline engine: turn the
SmartKey to position 3in the ignition lock
(Y page 157) and release it as soon as the
engine is running.
X To start a diesel engine: turn the Smart-
Key to position 2in the ignition lock
(Y page 157).
The 0028 preglow indicator lamp in the
instrument cluster lights up.
X When the 0028preglow indicator lamp
goes out, turn the SmartKey to position 3
(Y page 157) and release it as soon as the
engine is running. i
You can start the engine without preglow
if the engine is warm.
Using KEYLESS-GO to start the engine X
Depress the brake pedal and keep it
depressed.
X To start a gasoline engine: press the
Start/Stop button (Y page 158) once.
The engine starts.
X To start a diesel engine: press the Start/
Stop button once (Y page 158).
Preglow is activated and the engine starts.
i The Start/Stop button can be used to
start the vehicle without inserting the
SmartKey into the ignition lock. The Start/
Stop button must be inserted in the ignition
lock and the SmartKey must be in the vehi-
cle. This mode for starting the engine oper-
ates independently of the ECO start/stop
automatic engine start function. Pulling away
Automatic transmission G
WARNING
If the engine speed is above the idling speed
and you engage transmission position Dor R,
the vehicle could pull away suddenly. There is a risk of an accident.
When engaging transmission position Dor R,
always firmly depress the brake pedal and do not simultaneously accelerate.
X Depress the brake pedal and keep it
depressed.
X Shift the transmission to position Dor R
(Y page 168).
X Release the brake pedal.
X Carefully depress the accelerator pedal.
The electric parking brake (Y page 184) is
automatically released. 160
DrivingDriving and parking

Problems with the engine
Problem
Possible causes/consequences and
0050
0050Solutions The engine does not
start. The starter motor
can be heard. R
There is a malfunction in the engine electronics.
R There is a malfunction in the fuel supply.
X Before attempting to start the engine again, turn the SmartKey
in the ignition back to position 0or press the Start/Stop button
repeatedly until all indicator lamps in the instrument cluster go out.
X Try to start the engine again (Y page 159). Avoid excessively
long and frequent attempts to start the engine as these will drain
the battery.
If the engine does not start after several attempts:
X Consult a qualified specialist workshop. The engine does not
start. You cannot hear
the starter motor. The on-board voltage is too low because the battery is too weak or
discharged.
X Jump-start the vehicle (Y page 391).
If the engine does not start despite attempts to jump-start it:
X Consult a qualified specialist workshop. The starter motor was exposed to a thermal load that was too high.
X Allow the starter motor to cool down for approximately two
minutes.
X Try to start the engine again.
If the engine still does not start:
X Consult a qualified specialist workshop. Vehicles with a gaso-
line engine:
The engine is not run-
ning smoothly and is
misfiring. There is a malfunction in the engine electronics or in a mechanical
component of the engine management system.
X Only depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
X Have the cause rectified immediately at a qualified specialist
workshop. The coolant tempera-
ture gauge shows a
value above 248 ‡
(120 †). 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 369). Observe the warning
notes as you do so and add coolant if necessary. Driving
167Driving and parking Z

Opening the fuel filler flap
0043
To open the fuel filler flap
0044 To insert the fuel filler cap
0087 Fuel type to be used
0085 Tire pressure table
X Switch the engine off.
X Remove the SmartKey from the ignition
lock.
X KEYLESS-GO: open the driver’s door.
This corresponds to key position 0: "key
removed".
The driver’s door can be closed again.
X Press the fuel filler flap in the direction of
arrow 0043.
The fuel filler flap swings up.
X Turn the fuel filler flap counter-clockwise
and remove it.
X Insert the fuel filler cap into the holder
bracket on the inside of filler flap 0044.
X Completely insert the filler neck of the fuel
pump nozzle into the tank, hook in place
and refuel.
X Only fill the tank until the pump nozzle
switches off.
i Vehicles with a diesel engine: the filler
neck is designed for refueling at diesel fill-
ing pumps.
i Do not add any more fuel after the pump
stops filling for the first time. Otherwise,
fuel may leak out. Closing the fuel filler flap X
Replace the cap on the filler neck and turn
clockwise until it engages audibly.
X Close the fuel filler flap.
i Close the fuel filler flap before locking the
vehicle.
i If you are driving with the fuel filler cap
open, the 00B6reserve fuel warning lamp
flashes.
In addition, the 00B9Check Engine warning
lamp may light up (Y page 327).
A message appears in the multifunction
display (Y page 302).
For further information on warning and indi-
cator lamps in the instrument cluster, see
(Y page 327). Refueling
179Driving and parking Z

Servicing the brakes
!
If the red brake warning lamp lights up in
the instrument cluster and you hear a warn- ing tone while the engine is running, the
brake fluid level may be too low. Observe
additional warning messages in the multi-
function display.
The brake fluid level may be too low due to brake 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.
! Because ESP ®
is an automatic system,
the engine and ignition must be switched
off (SmartKey in position 0or 1or Start/
Stop button in position 0or 1) when the
electric parking brake is being tested on a
brake dynamometer (maximum
10 seconds).
Braking triggered automatically by ESP ®
may seriously damage the brake system.
All checks and maintenance work on the
brake system must be carried out at a quali-
fied specialist workshop. Consult a qualified
specialist workshop to arrange this.
Have brake pads installed and brake fluid
replaced at a qualified specialist workshop.
If the brake system has only been subject to
moderate loads, you should test the function- ality of your brakes at regular intervals. To doso, depress the brake pedal firmly when driv-
ing at a high speed. This improves the grip of
the brake pads.
You can find a description of Brake Assist
(BAS) on (Y page 68) or of BAS PLUS on
(Y page 69). Mercedes-Benz recommends that you only
have brake pads/linings installed on your
vehicle which have been approved for
Mercedes-Benz vehicles or which correspond
to an equivalent quality standard. Brake
pads/linings which have not been approved
for Mercedes-Benz vehicles or which are not
of an equivalent quality could affect your vehi-
cle's operating safety.
Mercedes-Benz recommends that you only
use brake fluid that has been specially
approved for your vehicle by Mercedes-Benz,
or which corresponds to an equivalent quality standard. Brake fluid which has not been
approved for Mercedes-Benz vehicles or
which is not of an equivalent quality could
affect your vehicle's operating safety.
High-performance brake system for
AMG vehicles The high-performance brake system is only
available on AMG vehicles.
The high-performance brake system is
designed for heavy loads. This may lead to
noise when braking. This will depend on:
R speed
R braking force
R environmental conditions, such as temper-
ature and humidity
The wear of individual components of the
brake system, such as the brake pads/linings
or brake discs, depends on the individual driv-
ing style and operating conditions.
For this reason, it is impossible to state a
mileage that will be valid under all circum-
stances. An aggressive driving style will lead
to high wear. You can obtain further informa- tion about this from your authorized
Mercedes-Benz Center.
New and replaced brake pads and discs only
reach their optimum braking effect after sev-
eral hundred kilometers of driving. Compen-
sate for this by applying greater force to the
brake pedal. Keep this in mind, and adapt Driving tips
189Driving and parking Z

Driving off-road increases the likelihood of
damage to the vehicle, which, in turn, can lead to failure of the mechanical assembly or sys-
tems. Adapt your driving style to suit the ter- rain conditions. Drive carefully. Have damage
to the vehicle rectified immediately at a quali-
fied specialist workshop.
Do not switch to transmission position N
when driving off-road. You could lose control
of the vehicle if you attempt to brake using
the service brake. If the gradient is too steep, drive backwards in reverse gear.
General notes Read this section carefully before driving your
vehicle off-road. Practice by driving over more gentle off-road terrain first.
Familiarize yourself with the characteristics
of your vehicle and the gear shift operation
before driving through difficult terrain.
The following driving systems are specially
adapted to off-road driving:
R Off-road program 1 and 2 (vehicles with the
ON&OFFROAD package) (Y page 251)
R LOW RANGE off-road gear (vehicles with
the ON&OFFROAD package)
(Y page 253)
R Differential lock (vehicles with the
ON&OFFROAD package) (Y page 252)
R Off-road ABS (Y page 68)
R Off-road 4ETS (Y page 73)
R AIRMATIC package (vehicle level)
(Y page 211)
R DSR (Downhill Speed Regulation)
(Y page 250)
Observe the following notes:
R Stop the vehicle before starting to drive
along an off-road route.
R For vehicles with the AIRMATIC pack-
age: select a vehicle level that is suitable
for the off-road terrain. To avoid damaging
the vehicle, make sure there is always suf-
ficient ground clearance. R
Check that items of luggage and loads are
stowed safely and are well secured
(Y page 339).
R Always keep the engine running and in gear
when driving on a downhill gradient. Acti-
vate DSR (Y page 250).
R Always keep the doors, tailgate, windows
and sliding sunroof closed while driving.
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 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 Look out for obstacles, such as rocks,
holes, tree stumps and furrows.
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 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 Always keep the engine running and in gear
when driving on a slope.
R Do not shift the automatic transmission to
transmission position N.
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. 192
Driving
tipsDriving an d parking

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 Engine oil level: check the engine oil level
and add oil if necessary.
When driving on steep gradients, the
engine oil level must be sufficiently high to
ensure a correct oil supply in the vehicle.
X DEF tank (BlueTEC vehicles): check the
level and top up if necessary (Y page 180).
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 Rims: dented or bent rims can result in a
loss of tire pressure and damage the tire
bead. Therefore, check your rims before
driving off-road and replace them as
required.
Checklist after driving off-road !
If you detect damage to the vehicle after
driving off-road, have the vehicle checked
immediately at a qualified specialist work-
shop.
X Vehicles with the ON&OFFROAD pack-
age: activate the on-road program
(Y page 251).
X Deactivate the LOW RANGE off-road gear
(Y page 253).
X Deactivate DSR (Y page 250).
X Vehicles with the AIRMATIC package:
lower the vehicle to a ride height suitable
for the road conditions, e.g. to the high-
way/high-speed level. X
Clean the headlamps and rear lights and
check for damage.
X Clean the front and rear license plates.
X Clean the wheels/tires with a water jet and
remove any foreign objects.
X Clean the wheels, wheel housings 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 bel-
lows 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.
X After 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.
X If you detect strong vibrations after off-road
travel, check for foreign objects in the
wheels and drive train and remove them if
necessary. Foreign objects can disturb the
balance and cause vibrations.
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.
Driving on sand Observe the following rules when driving on
sand:
R Vehicles with the ON&OFFROAD pack-
age: select off-road program 1
(Y page 251).
R Vehicles with the AIRMATIC package:
select a raised vehicle level.
R Avoid high engine speeds. Driving tips
193Driving and pa rking Z

R
When driving down an incline, make use of
the engine's braking effect. Observe the
engine speed; do not overrev the engine.
R Before driving on extreme uphill and down-
hill gradients, select the LOW RANGE off-
road gear (Y page 253).
R Drive slowly.
R Avoid high engine speeds. Drive at appro-
priate engine speeds (maximum
3,000 rpm).
R Use the left-hand paddle shifter to shift into
a lower gear in good time on long and steep
downhill gradients.
R Check the brakes after prolonged off-road
driving.
i Hill start assist will aid you when pulling
away on a hill.
For further information about hill start
assist, see (Y page 161).
Do not switch to transmission position N
when driving off-road. If you try to brake the
vehicle using the service brake, you could
lose control of the vehicle. If the gradient is
too steep for your vehicle, drive back down in
reverse gear.
Always observe the approach/departure
angle values (Y page 458).
Maximum gradient-climbing capability Always observe the maximum gradient climb-
ing ability values (Y page 458).
Hilltops When driving up an uphill gradient, slightly
reduce pressure on the accelerator immedi-
ately before reaching the brow of the hill. 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 the vehicle from traveling too quickly down
the other side Driving downhill 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 rollover.
R Shift to a lower gear using the left-hand
paddle shifter before tackling steep down-
hill gradients.
R Activate DSR. 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 Check that the brakes are working normally
after a long downhill stretch.
i The special off-road ABS setting enables a
precise, brief and repeated locking of the
front wheels. This causes them to dig into
loose earth. Be aware that the front wheels easily skid across the ground surface if
completely braked and therefore lose their
ability to steer. Driving systems
Cruise control
General notes Cruise control maintains a constant road
speed for you. It brakes automatically in order
to avoid exceeding the set speed. You must
select a lower gear in good time on long and
steep downhill gradients, especially if the
vehicle is laden or towing a trailer. By doing
so, you will make use of the braking effect of
the engine. This relieves the load on the brake
system and prevents the brakes from over-
heating and wearing too quickly.
Use cruise control only if road and traffic con-
ditions make it appropriate to maintain a
steady speed for a prolonged period. You can store any road speed above 20 mph
(30 km/h). Driving systems
195Driving and parking Z

sponding side lights up red. This warning is
always emitted when a vehicle enters the
blind spot monitoring range from behind or
from the side. When you overtake a vehicle,
the warning only occurs if the difference in
speed is less than 7 mph (12 km/h).
The yellow indicator lamp goes out if reverse gear is engaged. In this event, Blind Spot
Assist is no longer active.
The brightness of the indicator/warning
lamps is adjusted automatically according to
the ambient light.
Collision warning
If a vehicle is detected in the monitoring range
of Blind Spot Assist and you switch on the
corresponding turn signal, a double warning
tone sounds. Red warning lamp 0043flashes. If
the turn signal remains on, detected vehicles
are indicated by the flashing of red warning
lamp 0043. There are no further warning tones.
Switching on Blind Spot Assist
X Make sure that the radar sensor system
(Y page 279) and Blind Spot Assist
(Y page 276) are activated in the on-board
computer.
X Turn the SmartKey to position 2in the igni-
tion lock.
Warning lamps 0043in the exterior mirrors
light up red for approximately 1.5 seconds
and then turn yellow.
Towing a trailer
When you attach a trailer, make sure you have correctly established the electrical connec-
tion. This can be accomplished by checking
the trailer lighting. In this event, Blind Spot
Assist is deactivated. The indicator lamp in
the exterior mirrors lights up yellow, and the
Blind
Blind Spot SpotAssist
Assist Currently
Currently Unavail‐
Unavail‐
able See Operator's Manual
able See Operator's Manual message
appears in the multifunction display.
i You can deactivate the indicator lamps in
the exterior mirrors. To do so, switch off Blind Spot Assist when:
R the SmartKey is in position 2in the igni-
tion lock
R the engine is not running
R the electrical connection to the trailer
has been established
Lane Keeping Assist General notes
0043
Lane Keeping Assist camera
Lane Keeping Assist monitors the area in
front of your vehicle by means of a camera 0043
at the top of the windshield. Lane Keeping
Assist detects lane markings on the road and
warns you before you leave your lane unin-
tentionally.
If you select km kmon the on-board computer in
the Display Unit Speed-/Odometer
Display Unit Speed-/Odometer func-
tion (Y page 277), Lane Keeping Assist is
active starting at a speed of 60 km/h. If the
miles miles display unit is selected, the assistance
range begins at 40 mph.
A warning may be given if a front wheel
passes over a lane marking. It will warn you by means of intermittent vibration in the steer-
ing wheel for up to 1.5 seconds.
Important safety notes G
WARNING
Lane Keeping Assist may not always clearly
recognize lane markings. Driving systems
239Driving and parking
Z