check engine light MERCEDES-BENZ GLA-Class 2017 X156 User Guide

Problems with the seat heating
ProblemPossible causes/consequences andMSolutions
The seat heating has
switched off prema-
turely or cannot be
switched on.The on-board voltage is too low because too many electrical con-
sumers are switched on.
XSwitch off electrical consumers that you do not need, such as
the rear window defroster or interior lighting.
Once the battery is sufficiently charged, the seat heating will
switch back on automatically.
Steering wheel
Important safety notes
GWARNING
You could lose control of your vehicle if you do the following while driving:
Radjust the driver's seat, head restraint,
steering wheel or mirrors
Rfasten the seat belt
There is a risk of an accident.
Adjust the driver's seat, head restraint, steer-
ing wheel and mirror and fasten your seat belt before starting the engine.
GWARNING
Children could injure themselves if they
adjust the steering wheel. There is a risk of
injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
Adjusting the steering wheel
GWARNING
If the steering wheel is unlocked while the
vehicle is in motion, it could change position
unexpectedly. This could cause you to lose
control of the vehicle. There is a risk of an
accident.
Before starting off, make sure the steering
wheel is locked. Never unlock the steering
wheel while the vehicle is in motion.
:Release lever
;Adjusts the steering wheel height
=Adjusts the steering wheel position (fore-
and-aft adjustment)
XPush release lever :down completely.
The steering column is unlocked.
XAdjust the steering wheel to the desired
position.
XPush release lever :up completely.
The steering column is locked.
XCheck if the steering column is locked.
When doing so, try to push the steering
wheel up or down or try to move it in the
fore-and-aft direction.
108Steering wheel
Seats, steering wheel and mirrors

adjusted using COMAND or Audio 20 (see the
separate Operator's Manual).
Manual interior lighting control
XTo switch the front interior lighting on:
set the switch to thecposition.
XTo switch the front interior lighting off:
set the switch to the |position or (if the
door is closed) to the center position.
XTo switch the rear interior lighting on or
off: press the ubutton.
XTo switch the reading lamp on or off:
press the pbutton.
Crash-responsive emergency lighting
The interior lighting is activated automatically
if the vehicle is involved in an accident.
XTo switch off the crash-responsive
emergency lighting: press the hazard
warning lamp button.
or
XLock and then unlock the vehicle using the SmartKey.
Replacing bulbs
Important safety notes
Xenon bulbs
GDANGER
Xenon bulbscarry a high voltage. You can get
an electr icshock ifyou remove the cover of
the Xenon bulband touch the electrical con-
tacts. There isa risk of fatal injury.
Never touch the parts or the electrical con-
tacts of the Xenon bulb. Always have work on
the Xenon bulbscarried 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.
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.
Other bulbs
GWARNING
Bulbs, lamps and connectors can get very hot
when operating. Ifyou 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:
Ryou touch it
Rit is hot
Ryou drop it
Ryou 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. Only replace the
bulbs listed (
Ypage 122). Have the bulbs that
you cannot replace yourself changed at a
qualified specialist workshop.
If you require assistance replacing bulbs, con- sult a qualified specialist workshop.
If the new bulb still does not light up, consult
a qualified specialist workshop.
Replacing bulbs121
Lights and windshield wipers
Z

ProblemPossible causes/consequences andMSolutions
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.
XOnly depress the accelerator pedal slightly.
Otherwise, non-combusted fuel may get into the catalytic con-
verter and damage it.
XHave the cause rectified immediately at a qualified specialist
workshop.
The coolant tempera-
ture gauge shows a
value above 248 ‡
(120 †). The coolant
warning lamp may also
be on 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 (Ypage 311). Observe the warning
notes as you do so and add coolant if necessary.
DYNAMIC SELECT button (all vehicles
except Mercedes-AMG vehicles)
Use the DYNAMIC SELECT button to change
the drive program. Depending on the drive
program selected the following vehicle char-
acteristics will change:
Rthe drive (engine and transmission man-
agement)
Rthe steering
Rthe availability of the ECO start/stop func-
tion
Rthe climate control:
Each time you start the engine with the
SmartKey or the Start/Stop button, drive pro-
gram Cis activated. For further information
about starting the engine, see (
Ypage 151).
XPress DYNAMIC SELECT button :as many
times as necessary until the desired drive
program is selected.
The selected drive program appears in the
multifunction display. After five seconds
the display goes out and the status icon of
the selected drive program appears.
In addition, the current drive program set-
tings are displayed briefly in the Audio 20 or
COMAND display.
iIn a few countries, the ECO start/stop
function is deactivated at the factory due to the available fuel grade. In this case, the
ECO start/stop function is not available in
any drive program, regardless of the display
in the Audio 20 or COMAND display.
DYNAMIC SELECT button (all vehicles except Mercedes-AMG vehicles)157
Driving and parking
Z

!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.
Do not get into the vehicle again during the
refueling process. Otherwise, electrostatic
charge could build up again.
If you overfill the fuel tank, fuel could spray
out when the fuel pump nozzle is removed.
For further information on fuel and fuel quality (
Ypage 377).
Refueling
General information
The fuel filler flap is unlocked/locked auto-
matically when you unlock/lock the vehicle
with the SmartKey.
The position of the fuel filler cap is displayed
æ in the instrument cluster. The arrow on
the filling pump indicates the side of the vehi-
cle.
Opening the fuel filler flap
:To open the fuel filler flap
;Tire pressure table
=To insert the fuel filler cap
?Instruction label for fuel type to be refu-
eled
XVehicles without KEYLESS-GO: remove
the SmartKey from the ignition lock.
XVehicles with KEYLESS-GO start-func-
tion or KEYLESS-GO: open the driver's
door.
The on-board electronics now have status
0. This is the same as the SmartKey having
been removed.
XPress the fuel filler flap in the direction of
arrow :.
The fuel filler flap swings up.
XTurn the fuel filler cap counterclockwise
and remove it.
XInsert the fuel filler cap into the holder on
the inside of fuel filler flap =.
XCompletely insert the filler neck of the fuel
pump nozzle into the tank, hook in place
and refuel.
XOnly fill the tank until the pump nozzle
switches off.
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
XReplace the cap on the filler neck and turn
clockwise until it engages audibly.
XClose the fuel filler flap.
Close the fuel filler flap before locking the
vehicle.
If you are driving with the fuel filler cap open,
the 8 reserve fuel warning lamp flashes. A
message appears in the multifunction display
(
Ypage 252).
In addition, the ;Check Engine warning
lamp may light up (
Ypage 275).
For further information on warning and indi-
cator lamps in the instrument cluster, see
(
Ypage 275).
170Refueling
Driving and parking

Servicing the brakes
!The brake fluid level may be too low, if:
Rif the red brake warning lamp lights up inthe instrument cluster and
Ryou hear a warning tone while the engineis running
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 immedi-
ately. Consult a qualified specialist work-
shop to arrange this.
!A function or performance test should
only be carried out on a 2-axle dynamom-
eter. If you wish to operate the vehicle on
such a dynamometer, please consult a
qualified specialist workshop in advance.
You could otherwise 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:
Rthe electric parking brake is tested on a
brake dynamometer (for a maximum of
ten seconds)
Rthe vehicle is towed with the front axle
raised.
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.
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.
You can find a description of Brake Assist
(BAS) on (
Ypage 66).
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.
Checking brake lining thickness
You can measure the break pad/lining thick- ness using a test gage. Color-coding (green or
red) on the test gage allows you to determine
whether the brake pad/lining thickness is still
sufficient. The test gage is in the vehicle docu-
ment wallet in the glove box.
Front wheel
178Driving tips
Driving and parking

function cannot hold the vehicle on such sur-
faces.
Checklist before driving off-road
XEngine 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.
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.
XRims: dented or bent rims can result in a
loss of tire pressure and damage the tire
bead. Before driving off-road, check the
wheels and replace them if necessary.
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.
XDeactivate off-road program (Ypage 157).
XDeactivate DSR (Ypage 197).
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, wheel housings 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 bel-
lows 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 in sand, mud, gravel, water or
similar dirty conditions, have the following
checked and cleaned:
Rbrake discs
Rwheels
Rbrake pads
Raxle joints
XIf 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 poor road surfaces 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.
Driving on sand
Observe the following rules when driving on
sand:
RActivate the off-road program
(
Ypage 157).
RAvoid high engine speeds.
RUse the left-hand steering wheel paddle
shifter to shift to a lower gear appropriate
to the terrain.
RDrive quickly to overcome the rolling resist-ance. Otherwise the vehicle's wheels could
become stuck in loose ground.
RDrive in the tracks of other vehicles if pos-
sible. Make sure that:
-the tire ruts are not too deep.
-the sand is sufficiently firm.
-the ground clearance of the vehicle is
sufficient.
Tire ruts and gravel roads
!Check that the ruts are not too deep and
that your vehicle has sufficient clearance.
182Driving tips
Driving and parking

RActivate 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.
RCheck that the brakes are working normally
after a long downhill stretch.
Off-road ABS is activated when the off-road
program is selected.
At speeds below 18 mph (30 km/h), the front
wheels lock cyclically during braking. The dig-
ging-in effect achieved in the process reduces the stopping distance on off-road terrain. The
steerability of the vehicle is considerably
reduced if the wheels lock.
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. On long and
steep downhill gradients, especially if the
vehicle is laden, you must select a low gear in
good time. You need to have previously selec-
ted manual gearshifting M(
Ypage 166). 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 overheating 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).
The speed indicated in the speedometer may
differ slightly from the speed stored.
Important safety notes
If you fail to adapt your driving style, cruise
control can neither reduce the risk of an acci-
dent nor override the laws of physics. Cruise
control cannot take into account the road,
traffic and weather conditions. Cruise control is only an aid. You are responsible for the dis-
tance to the vehicle in front, for vehicle speed,
for braking in good time and for staying in
your lane.
Do not use cruise control:
Rin road and traffic conditions which do not
allow you to maintain a constant speed e.g.
in heavy traffic or on winding roads
Ron slippery road surfaces. Braking or accel-
erating could cause the drive wheels to lose
traction and the vehicle could then skid
Rwhen there is poor visibility, e.g. due to fog,
heavy rain or snow
If there is a change of drivers, advise the new
driver of the speed stored.
Cruise control lever
:To activate or increase speed
;To activate or reduce speed
=To deactivate cruise control
?To activate at the current speed/last
stored speed
When you activate cruise control, the stored
speed is shown in the multifunction display
for five seconds.
Activation conditions
To activate cruise control, all of the following
activation conditions must be fulfilled:
Rthe electric parking brake must be
released.
RESP®must be active, but not intervening.
184Driving systems
Driving an d parking

ProblemPossible causes/consequences andMSolutions
F(USA only)
! (Canada only)
The red indicator lamp
for the electric parking
brake flashes or lights
up and/or the yellow
warning lamp for the
electric parking brake
lights up.XObserve the additional display messages in the multifunction
display.
6
The red restraint sys-
tem warning lamp is lit
while the engine is run-
ning.The restraint system is faulty.
GWARNING
The air bags or Emergency Tensioning Devices may either be trig-
gered unintentionally or, in the event of an accident, may not be
triggered.
There is an increased risk of injury.
XObserve the additional display messages in the multifunction
display.
XDrive on carefully.
XContact a qualified specialist workshop and have the restraint
system checked.
For further information about the restraint system, see
(
Ypage 42).
274Warning and indicator lamps in the instrument cluster
On-board computer and displays

Engine
ProblemPossible causes/consequences andMSolutions
;
The yellow Check
Engine warning lamp
lights up while the
engine is running.There may be a malfunction, for example:
Rin the engine management
Rin the fuel injection system
Rin the exhaust system
Rin the ignition system
Rin the fuel system
The emission limit values may be exceeded and the engine may be
in emergency mode.
XVisit a qualified specialist workshop immediately.
iIn some states, you must immediately visit a qualified special-
ist workshop as soon as the yellow Check Engine warning lamp
lights up. This is due to the legal requirements in effect in these
states. If in doubt, check whether such legal regulations apply in the state in which you are currently driving.
æ
The yellow reserve fuel
warning lamp lights up
while the engine is run-
ning.The fuel level has dropped into the reserve range.
XRefuel at the nearest gas station.
æ
The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion.
In addition, the ;
Check Engine warning
lamp may light up.The fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.
XCheck that the fuel filler cap is correctly closed.
XIf the fuel filler cap is not correctly closed: close the fuel filler
cap.
XIf the fuel filler cap is closed: visit a qualified specialist work-
shop.
?
The red coolant warn-
ing lamp lights up while
the engine is running
and the coolant tem-
perature gage is at the
start of the scale.The temperature sensor for the coolant temperature gage is defec-
tive.
The coolant temperature is no longer being monitored. There is a
risk of engine damage if the coolant temperature is too high.
XPull over and stop the vehicle safely and switch off the engine,
paying attention to road and traffic conditions. Do not continue
driving under any circumstances.
XSecure the vehicle against rolling away (Ypage 171).
XConsult a qualified specialist workshop.
Warning and indicator lamps in the instrument cluster275
On-board computer and displays
Z

ProblemPossible causes/consequences andMSolutions
XLeave the vehicle and keep a safe distance from the vehicle until
the engine has cooled down.
XCheck the coolant level and add coolant, observing the warning
notes (
Ypage 311).
XIf you have to add coolant frequently, have the engine cooling
system checked.
XMake sure that the air supply to the engine radiator is not
blocked, e.g. by snow, slush or ice.
XAt coolant temperatures below 248 ‡ (120 †), drive to the
nearest qualified specialist workshop.
XAvoid heavy loads on the engine as you do so, e.g. driving in
mountainous terrain and stop-start traffic.
Driving systems
ProblemPossible causes/consequences and MSolutions
·
The red distance warn-
ing lamp lights up while
the vehicle is in motion.
A warning tone also
sounds.You are approaching a vehicle or a stationary obstacle in your line
of travel at too high a speed.
XBe prepared to brake immediately.
XPay careful attention to the traffic situation. You may have to
brake or take evasive action.
For further information about the distance warning function of
COLLISION PREVENTION ASSIST PLUS, see (
Ypage 66).
Warning and indicator lamps in the instrument cluster277
On-board computer and displays
Z