MERCEDES-BENZ CLA 2019 Repair Manual

You can thus avoid the risks that could arise asa result of:
Ran incorrectly categorized person in the front-passenger seat
Rthe unintentional deactivation of the front-passenger front air bag
Rthe unsuitable positioning of the childrestraint system, e.g. too close to the dash-board
Rearward-facing child restraint system
If it is absolutely necessary to install a rearward-facing child restraint system on the front-passenger seat, always make sure that thefront-passenger front air bag is deactivated.Only if the PASSENGER AIR BAG OFF indicatorlamp is permanently lit (Ypage 41) is the front-passenger front air bag deactivated.
Always observe the child restraint system man-ufacturer's installation and operating instruc-tions.
Forward-facing child restraint system
If it is absolutely necessary to install a forward-facing child restraint system on the front-passenger seat, always move the front-passenger seat as far back as possible. Fullyretract the seat cushion length. The entire baseof the child restraint system must always rest onthe seat cushion of the front-passenger seat.The backrest of the child restraint system mustlie as flat as possible against the backrest of thefront-passenger seat. The child restraint systemmust not touch the roof or be subjected to a loadby the head restraint. Adjust the angle of theseat backrest and the head restraint positionaccordingly. Always make sure that the shoul-der belt strap is correctly routed from the vehi-cle belt outlet to the shoulder belt guide on thechild restraint system. The shoulder belt strapmust be routed forward and down from the vehi-cle belt outlet. If necessary, adjust the vehiclebelt outlet and the front-passenger seat accord-ingly.
Always observe the child restraint system man-ufacturer's installation and operating instruc-tions.
Child-proof locks
Important safety notes
GWARNING
If children are traveling in the vehicle, they
could:
Ropen doors, thus endangering other people
or road users
Rexit the vehicle and be caught by oncoming
traffic
Roperate vehicle equipment and become
trapped
There is a risk of an accident and injury.
Always activate the child-proof locks and
override feature if children are traveling in the
vehicle. When leaving the vehicle, always take
the key with you and lock the vehicle. Never
leave children unattended in the vehicle.
Override feature for:
Rthe rear doors (Ypage 60)
Rthe rear side windows (Ypage 60)
GWARNING
If you leave children unsupervised in the vehi-
cle, they could set it in motion by, for example:
Rrelease the parking brake.
Rshift the automatic transmission out of the
parking positionP.
Rstart the engine.
In addition, they may operate vehicle equip-
ment and become trapped. There is a risk of
an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children unsupervised in the vehicle.
GWARNING
If persons, particularly children are subjected
to prolonged exposure to extreme heat or
cold, there is a risk of injury, possibly even
fatal. Never leave children unattended in the
vehicle.
Children in the vehicle59
Safety
Z

GWARNING
If the child restraint system is subjected to
direct sunlight, parts may get very hot. Chil-
dren may burn themselves on these parts,
particularly on the metal parts of the child
restraint system. There is a risk of injury.
If you leave the vehicle, taking the child with
you, always ensure that the child restraint
system is not exposed to direct sunlight. Pro-
tect it with a blanket, for example. If the child
restraint system has been exposed to direct
sunlight, let it cool down before securing the
child in it. Never leave children unattended in
the vehicle.
Child-proof locks for the rear doors
You secure each door individually with the child-proof locks on the rear doors. A door securedwith a child-proof lock cannot be opened frominside the vehicle. When the vehicle is unlocked,the door can be opened from the outside.
XTo activate:press the child-proof lock leverup in the direction of arrowC.
XMake sure that the child-proof locks are work-ing properly.
XTo deactivate:press the child-proof locklever down in the direction of arrowD.
Override feature for the rear side win-
dows
XTo activate/deactivate:press buttonC.If indicator lampDis lit, operation of the rearside windows is disabled. Operation is onlypossible using the switches in the driver'sdoor. If indicator lampDis off, operation ispossible using the switches in the rear com-partment.
Pets in the vehicle
GWARNING
If you leave animals unsupervised or unse-
cured in the vehicle, they may press buttons
or switches, for instance.
In this way, animals may:
Ractivate vehicle equipment and become
trapped, for example
Rswitch systems on or off and thereby
endanger other road users
Furthermore, unsecured animals may be flung
around inside the vehicle in the event of an
accident or abrupt steering or braking maneu-
ver, and thereby injure vehicle occupants.
There is a risk of accident and injury.
Never leave animals unattended in the vehi-
cle.
Always secure animals properly when driving,
for instance with a suitable pet carrier.
60Pets in the vehicle
Safety

Driving safety systems
Overview of driving safety systems
In this section, you will find information aboutthe following driving safety systems:
RABS (Anti-lockBrakingSystem)(Ypage 61)
RBAS (BrakeAssistSystem) (Ypage 61)
RActive Brake Assist (Ypage 62)
RESP®(ElectronicStabilityProgram)(Ypage 64)
REBD (ElectronicBrake forceDistribution)(Ypage 67)
RADAPTIVE BRAKE (Ypage 68)
RSTEER CONTROL (Ypage 68)
Important safety notes
If you fail to adapt your driving style or if you areinattentive, the driving safety systems can nei-ther reduce the risk of an accident nor overridethe laws of physics. Driving safety systems aremerely aids designed to assist driving.
You are responsible for maintaining the distanceto the vehicle in front, for vehicle speed, forbraking in good time, and for staying in lane.Always adapt your driving style to suit the pre-vailing road and weather conditions and main-tain a safe distance from the vehicle in front.Drive carefully.
The driving safety systems described only workas effectively as possible when there is ade-quate contact between the tires and the roadsurface. Please pay special attention to thenotes on tires, recommended minimum tiretread depths, etc. (Ypage 291).
In wintry driving conditions, always use wintertires (M+S tires)and if necessary, snow chains.Only in this way will the driving safety systemsdescribed in this section work as effectively aspossible.
ABS (Anti-lock Braking System)
General information
ABS regulates brake pressure in such a way thatthe wheels do not lock when you brake. Thisallows you to continue steering the vehicle whenbraking.
The%ABS warning lamp in the instrumentcluster lights up when the ignition is switchedon. It goes out when the engine is running.
ABS works from a speed of about 5 mph(8 km/h), regardless of road-surface conditions.ABS works on slippery surfaces, even when youonly brake gently.
Important safety notes
iObserve the "Important safety notes" sec-tion (Ypage 61).
GWARNING
If ABS is malfunctioning, the wheels could
lock when braking. The steerability and brak-
ing characteristics would be severely affec-
ted. There is an increased danger of skidding
and accidents.
Drive on carefully. Have ABS checked imme-
diately at a qualified specialist workshop.
When ABS is malfunctioning, other systems,including driving safety systems, will alsobecome inoperative. Observe the informationon the ABS warning lamp (Ypage 222)and dis-play messages which may be shown in theinstrument cluster (Ypage 194).
Braking
XIf ABS intervenes:continue to depress thebrake pedal vigorously until the braking sit-uation is over.
XTo make a full brake application:depressthe brake pedal with full force.
If ABS intervenes when braking, you will feel apulsing in the brake pedal.
The pulsating brake pedal can be an indicationof hazardous road conditions, and functions as areminder to take extra care while driving.
BAS (Brake Assist System)
General information
BAS operates in emergency braking situations.If you depress the brake pedal quickly, BASautomatically boosts the braking force, thusshortening the stopping distance.
Driving safety systems61
Safety
Z

Important safety notes
iObserve the "Important safety notes" sec-tion (Ypage 61).
GWARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
Braking
XKeep the brake pedal firmly depressed untilthe emergency braking situation is over.ABS prevents the wheels from locking.
The brakes will function as usual once yourelease the brake pedal. BAS is deactivated.
Active Brake Assist
General information
iObserve the "Important safety notes" sec-tion (Ypage 61).
Active Brake Assist consists of a distance warn-ing function with an autonomous braking func-tion and a situation-dependent brake boostingeffect.
Active Brake Assist can help you to minimize therisk of a collision with the vehicle traveling infront or reduce the effects of such a collision.
If Active Brake Assist detects that there is a riskof collision, you will be warned visually andacoustically. If you do not react to the visualcollision warning or the warning tone, autono-mous braking can be initiated in critical situa-tions. If you apply the brake yourself in a criticalsituation, Active Brake Assist supports you witha situation-dependent brake boosting effect.
Important safety notes
Detection of hazardous situations can be par-ticularly impaired if:
RThere is dirt on the sensors or anything elsecovering the sensors
RThere is snow or heavy rain
RThere is interference by other radar sources
RThere are strong radar reflections, for exam-ple in parking garages
RA narrow vehicle is traveling in front, e.g. amotorcycle
RA vehicle is traveling in front on a different line
RYou are driving a new vehicle or servicing onthe Active Brake Assist system has just beencarried out
Observe the important safety notes in the"Breaking-in notes" section (Ypage 122).
Following damage to the front end of the vehicle,have the configuration and operation of theradar sensor checked at a qualified specialistworkshop. This also applies to collisions at lowspeeds where no visible damage to the front ofthe vehicle is apparent.
Activating/deactivating
Active Brake Assist is active after every ignitioncycle.
You can activate or deactivate Active BrakeAssist (Ypage 187) in the on-board computer.When deactivated, the distance warning func-tion and the autonomous braking function arealso deactivated.
If Active Brake Assist is deactivated, the

The distance warning function may not give
warnings in all critical situations. There is a
risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
Always adapt your speed to suit the prevailing
road and traffic conditions.
GWARNING
The distance warning function cannot always
clearly identify objects and complex traffic
situations.
In such cases, the distance warning function
may:
Rgive an unnecessary warning
Rnot give a warning
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and do not rely solely on the distance
warning function.
Function
Starting at a speed of approximately 4 mph(7 km/h), the distance warning function warnsyou if you rapidly approach a vehicle in front. Anintermittent warning tone will then sound, andthe

Situation-dependent braking assistance is capa-ble of reacting to moving objects that havealready been detected as such at least onceover the period of observation, up to vehiclespeeds of around 155 mph (250 km/h).
Situation-dependent braking assistance canalso detect stationary objects, up to vehiclespeeds of around 44 mph (70 km/h).
XKeep the brake pedal depressed until theemergency braking situation is over.ABS prevents the wheels from locking.
The brakes will work normally again if:
Ryou release the brake pedal
Rthere is no longer any danger of a collision
Rno obstacle is detected in front of your vehicle
Situation-dependent braking assistance is thendeactivated.
Important safety notes
iObserve the "Important safety notes" sec-tion for driving safety systems (Ypage 61).
GWARNING
Active Brake Assist does not react:
Rto persons, bicycles, motorcycles or ani-
mals
Rto approaching vehicles
Rto cross traffic
Ron bends
As a result, Active Brake Assist cannot inter-
vene in all critical situations. There is a risk of
an accident.
Always pay careful attention to the traffic sit-
uation and be prepared to brake.
GWARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist might:
Rintervene unnecessarily
Rnot intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
Due to the nature of the system, complex butnon-critical driving conditions may also causeActive Brake Assist to intervene.
Even if Active Brake Assist is not available due toa malfunction in the radar sensor system, thebrake system is still available with full brakeboosting effect and BAS.
ESP®(Electronic Stability Program)
General notes
iObserve the "Important safety notes" sec-tion (Ypage 61).
ESP®monitors driving stability and traction, i.e.power transmission between the tires and theroad surface.
If ESP®detects that the vehicle is deviating fromthe direction desired by the driver, one or morewheels are braked to stabilize the vehicle. Theengine output is also modified to keep the vehi-cle on the desired course within physical limits.
ESP®assists the driver when pulling away on
wet or slippery roads. ESP®can also stabilizethe vehicle during braking.
ETS/4ETS (Electronic Traction System)
iObserve the "Important safety notes" sec-tion (Ypage 61).
ETS traction control is part of ESP®. On vehicles
with 4MATIC, 4ETS is part of ESP®.
Traction control brakes the drive wheels indi-vidually if they spin. This enables you to pullaway and accelerate on slippery surfaces, forexample if the road surface is slippery on oneside. In addition, more drive torque is transfer-red to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP®.
Important safety notes
iObserve the "Important safety notes" sec-tion (Ypage 61).
GWARNING
If ESP®is malfunctioning, ESP®is unable to
stabilize the vehicle. Additionally, further driv-
ing safety systems are deactivated. This
increases the risk of skidding and an accident.
64Driving safety systems
Safety

Drive on carefully. Have ESP®checked at a
qualified specialist workshop.
Vehicles without 4MATIC:when towing yourvehicle with the front axle raised, it is important
that you observe the notes on ESP®
(Ypage 286).
If the

Characteristics when ESP®is deactivated
If ESP®is deactivated and one or more wheels
start to spin, the

XTo deactivate ESP®:press buttonCuntil
the

You should therefore adapt your driving style
to the different handling characteristics. Have
the brake system checked at a qualified spe-
cialist workshop.
Please observe the information on warning andindicator lamps (Ypage 222)
(Ypage 222) as well as on display messages(Ypage 196).
ADAPTIVE BRAKE
ADAPTIVE BRAKE enhances braking safety andoffers increased braking comfort. In addition tothe braking function, ADAPTIVE BRAKE also hasthe HOLD function (Ypage 158) and hill startassist (Ypage 126).
STEER CONTROL
General information
STEER CONTROL helps you by transmitting anoticeable steering force to the steering wheelin the direction required for vehicle stabilization.
This steering assistance is provided in particularif:
Rboth right wheels or both left wheels are on awet or slippery road surface when you brake
Rthe vehicle begins to skid
Important safety notes
iObserve the "Important safety notes" sec-tion (Ypage 61).
No steering assistance is provided from STEERCONTROL, if:
RESP®is malfunctioning
Rthe steering is malfunctioning
If ESP®is malfunctioning, you will be assistedfurther by the electrical power steering.
Protection against theft
Immobilizer
The immobilizer prevents your vehicle frombeing started without the correct SmartKey.
XTo activate with the SmartKey:remove theSmartKey from the ignition lock.
XTo activate with KEYLESS-GO start-func-tion or KEYLESS-GO:switch the ignition offand open the driver's door.
XTo deactivate:switch on the ignition.
When leaving the vehicle, always take theSmartKey with you and lock the vehicle. Anyonecan start the engine if a valid SmartKey has beenleft inside the vehicle.
iThe immobilizer is always deactivated whenyou start the engine.
In the event that the engine cannot be started(yet the vehicle's battery is charged), the sys-tem is not operational. Contact an authorizedMercedes-Benz Center or call1-800-FOR-MERCedes (in the USA) or1-800-387-0100(in Canada).
ATA (anti-theft alarm system)
XTo arm:lock the vehicle with the SmartKey orKEYLESS-GO.Indicator lampCflashes. The alarm systemis armed after approximately 15 seconds.
XTo disarm:unlock the vehicle with the Smart-Key or KEYLESS-GO.
or
XInsert the SmartKey into the ignition lock.
A visual and audible alarm is triggered if thealarm system is armed and you open:
Ra door
Rthe vehicle with the mechanical key
Rthe trunk lid
Rthe hood
68Protection against theft
Safety