check engine light MERCEDES-BENZ GLA 2016 User Guide

Servicing the brakes
! The brake fluid level may be too low, if: R
if the red brake warning lamp lights up in
the instrument cluster and R
you hear a warning tone while the engine
is 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 0 or 1 in the ignition lock) if:R
the electric parking brake is tested on a
brake dynamometer (for a maximum of
ten seconds) R
the 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 ( Y
page 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 wheel178
Driving tips
Driving and parking

function cannot hold the vehicle on such sur-
faces.
Checklist before driving off-road 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
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. 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. X
Deactivate off-road program ( Y
page 157).X
Deactivate DSR ( Y
page 197).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, 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 in sand, mud, gravel, water or
similar dirty conditions, have the following
checked and cleaned: R
brake discs R
wheels R
brake pads R
axle joints 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 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: R
Activate the off-road program
( Y
page 157). R
Avoid high engine speeds. R
Use the left-hand steering wheel paddle
shifter to shift to a lower gear appropriate
to the terrain. R
Drive quickly to overcome the rolling resist-
ance. Otherwise the vehicle's wheels could
become stuck in loose ground. R
Drive 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.182
Driving tips
Driving and parking

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.
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 ( Y
page 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: R
in road and traffic conditions which do not
allow you to maintain a constant speed e.g.
in heavy traffic or on winding roads 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
If there is a change of drivers, advise the new
driver of the speed stored.
Cruise control lever
C
To activate or increase speed D
To activate or reduce speed

Problem
Possible causes/consequences and P Solutions
I (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. X
Observe the additional display messages in the multifunction
display.
u
The red restraint sys-
tem warning lamp is lit
while the engine is run-
ning. The restraint system is faulty.
G WARNING
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. X
Observe the additional display messages in the multifunction
display. X
Drive on carefully. X
Contact a qualified specialist workshop and have the restraint
system checked.
For further information about the restraint system, see
( Y
page 42).274
Warning and indicator lamps in the instrument cluster
On-board computer and displays

ing the vehicle or charging the battery, gases
can escape from the battery. There is a risk of
an explosion.
Allow the frozen battery to thaw out before
charging it or jump-starting.
! Only use battery chargers with a maxi-
mum charging voltage of 14.8 V.
! Only charge the battery using the jump-
starting connection point.
The jump-starting connection point is in the
engine compartment ( Y
page 331).X
Open the hood. X
Connect the battery charger to the positive
terminal and ground point in the same
order as when connecting the donor bat-
tery in the jump-starting procedure
( Y
page 331).
If the indicator/warning lamps do not light up
at low temperatures, it is very likely that the
discharged battery has frozen. In this case
you may neither jump-start the vehicle nor
charge the battery. The service life of a
thawed-out battery may be shorter. The start-
ing characteristics can be impaired, particu-
larly at low temperatures. Have the thawed-
out battery checked at a qualified specialist
workshop.
Only charge the installed battery with a bat-
tery charger which has been tested and
approved by Mercedes-Benz. A battery
charger unit specially adapted for Mercedes-
Benz vehicles and tested and approved by
Mercedes-Benz is available as an accessory.
It permits the charging of the battery in its
installed position. Contact an authorized
Mercedes-Benz Center for further informa-
tion and availability. Read the battery charg-
er's operating instructions before charging
the battery.330
Battery (vehicle)
Breakdown assistance

Jump-starting For the jump-starting procedure, use only the jump-starting connection point, consisting of a
positive terminal and a ground point, in the engine compartment.
G WARNING
Battery acid is caustic. There is a risk of injury.
Avoid contact with skin, eyes or clothing. Do not inhale any battery gases. Do not lean over the
battery. Keep children away from batteries. Wash away battery acid immediately with plenty of
clean water and seek medical attention.
G WARNING
During charging and jump-starting, explosive gases can escape from the battery. There is a risk
of an explosion.
Particularly avoid fire, open flames, creating sparks and smoking. Ensure there is sufficient ven-
tilation while charging and jump-starting. Do not lean over a battery.
G WARNING
During the charging process, a battery produces hydrogen gas. If a short circuit occurs or sparks
are created, the hydrogen gas can ignite. There is a risk of an explosion. R
Make sure that the positive terminal of a connected battery does not come into contact with
vehicle parts. R
Never place metal objects or tools on a battery. R
It is important that you observe the described order of the battery terminals when connecting
and disconnecting a battery. R
When jump-starting, make sure that the battery poles with identical polarity are connected. R
It is particularly important to observe the described order when connecting and disconnecting
the jumper cables. R
Never connect or disconnect the battery terminals while the engine is running.
G WARNING
A discharged battery can freeze at temperatures below freezing point. When jump-starting the
vehicle or charging the battery, gases can escape from the battery. There is a risk of an explosion.
Allow the frozen battery to thaw out before charging it or jump-starting.
! Avoid repeated and lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
If the indicator/warning lamps do not light up at low temperatures, it is very likely that the
discharged battery has frozen. In this case you may neither jump-start the vehicle nor charge
the battery. Let the battery thaw first. The service life of a thawed-out battery may be shorter.
The starting characteristics can be impaired, particularly at low temperatures. Have the
thawed-out battery checked at a qualified specialist workshop. Jump-starting 331
Breakdown assistance Z