check engine MERCEDES-BENZ CLA 2019 User Guide

ProblemPossible causes/consequences andPPSolutions
KEYLESS-GO is malfunctioning.
XLock/unlock the vehicle using the remote control function of theSmartKey.
XHave the vehicle and SmartKey checked at a qualified specialistworkshop.
If the vehicle can also not be locked/unlocked using the remote con-trol function:
XUnlock (Ypage 77) or lock (Ypage 77) the vehicle using themechanical key.
XHave the vehicle and SmartKey checked at a qualified specialistworkshop.
The engine cannot bestarted using the Smart-Key.
The on-board voltage is too low
XSwitch off non-essential consumers, e.g. seat heating or interiorlighting, and try to start the engine again.
If this does not work:
XCheck the starter battery and charge it if necessary (Ypage 281).
or
XJump-start the vehicle (Ypage 282).
or
XConsult a qualified specialist workshop.
The engine cannot bestarted using the Start/Stop button. The Smart-Key is in the vehicle.
The vehicle is locked.
XUnlock the vehicle and try to start the vehicle again.
The SmartKey battery is discharged or nearly discharged.
XCheck the SmartKey battery (Ypage 73) and replace it if necessary(Ypage 73).
If this does not work:
XStart your vehicle with the SmartKey in the ignition lock.
There is interference from a powerful source of radio waves.
XStart your vehicle with the SmartKey in the ignition lock.
You have lost a Smart-Key.XHave the SmartKey deactivated at a qualified specialist workshop.
XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
You have lost themechanical key.XReport the loss immediately to the vehicle insurers.
XIf necessary, have the locks changed as well.
SmartKey75
Opening and closing
Z

XPress the locking button on the driver’s door(Ypage 76).
XCheck whether the locking knobs on thefront-passenger door and the rear doors arestill visible. Press down the locking knobs byhand, if necessary.
XClose the driver's door.
XTake the mechanical key out of the SmartKey(Ypage 72).
XInsert the mechanical key into the lock of thedriver's door as far as it will go.
XTurn the mechanical key clockwise as far as itwill go to positionG.
XTurn the mechanical key back and remove it.
XMake sure that the doors and the trunk lid arelocked.
XInsert mechanical key into the SmartKey(Ypage 72).
iIf you lock the vehicle as described above,the fuel filler flap is not locked. The anti-theftalarm system is not armed.
Trunk
Important safety notes
GWARNING
Combustion engines emit poisonous exhaust
gases such as carbon monoxide. Exhaust
gases can enter the vehicle interior if the
trunk lid is open when the engine is running,
especially if the vehicle is in motion. There is a
risk of poisoning.
Always switch off the engine before opening
the trunk lid. Never drive with the trunk lid
open.
GWARNING
If objects, luggage or loads are not secured or
not secured sufficiently, they could slip, tip
over or be flung around and thereby hit vehicle
occupants. There is a risk of injury, particu-
larly in the event of sudden braking or a sud-
den change in direction.
Always store objects so that they cannot be
flung around. Secure objects, luggage or
loads against slipping or tipping before the
journey.
!The trunk lid swings upwards when opened.Therefore, make sure that there is sufficientclearance above the trunk lid.
The opening dimensions of the trunk lid can befound in the "Vehicle data" section(Ypage 325).
You should preferably place luggage or loads inthe trunk. Observe the loading guidelines(Ypage 239).
Do not leave the SmartKey in the trunk. Youcould otherwise lock yourself out.
The trunk lid can be:
Ropened and closed manually from outside
Ropened automatically from outside
Ropened automatically from inside
Ropened from the inside using the emergencyrelease
Tailgate obstruction detection with
reversing feature
On vehicles with an EASY-PACK tailgate, thetailgate is equipped with automatic obstaclerecognition with a reversing feature. If a solidobject blocks or restricts the tailgate when auto-matically opening or closing, this procedure isstopped. If the tailgate is stopped during theclosing process, the tailgate automaticallyopens again slightly. The automatic obstructiondetection with reversing feature is only an aid. Itis not a substitute for your attentiveness whenopening and closing the tailgate.
78Trunk
Opening and closing

!Do not warm up the engine while stationary.Pull away immediately. Avoid high enginespeeds and full throttle until the engine hasreached its operating temperature.
In vehicles with automatic transmission,engage positions P and R only when the vehi-cle is stationary.
Where possible, avoid spinning the drivewheels when pulling away on slippery roads.You could otherwise damage the drive train.
!Mercedes-AMG vehicles:avoid full-loadoperation and engine speeds greater than5000 rpm when the engine is cold. This helpsto protect the engine and avoids uncomfort-able driving.
Key positions
SmartKey
ZTo remove the SmartKey
(shift the transmission to position])
GPower supply for some consumers, such asthe windshield wipers
HIgnition (power supply for all consumers)and drive position
ITo start the engine
iThe SmartKey can be turned in the ignitionlock even if it is not the correct SmartKey forthe vehicle. The ignition is not switched on.The engine cannot be started.
Start/Stop button
General notes
Vehicles with KEYLESS-GO are equipped withSmartKeys featuring the integrated KEYLESS-GO function and a detachable Start/Stop but-ton.
A check which periodically establishes a radioconnection between the vehicle and the Smart-Key determines whether a valid SmartKey is inthe vehicle. This occurs, for example, whenstarting the engine.
When you insert the Start/Stop button into theignition lock, the system needs approximatelytwo seconds recognition time. You can then usethe Start/Stop button.
Pressing the Start/Stop button several times insuccession corresponds to the different Smart-Key positions in the ignition lock. This is only thecase if you are not depressing the brake pedal.
If you depress the brake pedal and press theStart/Stop button, the engine starts immedi-ately.
To start the vehicle without actively using theSmartKey:
Rthe Start/Stop button must be inserted in theignition lock
Rthe SmartKey must be in the vehicle
Rthe vehicle must not be locked with theSmartKey or KEYLESS-GO (Ypage 71)
Do not keep the KEYLESS-GO key:
Rwith electronic devices, e.g. a mobile phoneor another SmartKey.
Rwith metallic objects, e.g. coins or metal foil.
Rinside metallic objects, e.g. a metal case.
This can affect the functionality of KEYLESS-GO.
If you lock the vehicle with the SmartKey remotecontrol or with KEYLESS-GO, after a short time:
Ryou will not be able to switch on the ignitionwith the Start/Stop button.
Ryou will no longer be able to start the enginewith the Start/Stop button until the vehicle isunlocked again.
If you lock the vehicle centrally using the buttonon the front door (Ypage 76), you can continueto start the engine with the Start/Stop button.
The engine can be switched off while the vehicleis in motion by pressing and holding the Start/Stop button for three seconds. This functionoperates independently of the ECO start/stopautomatic engine switch-off function.
Driving123
Driving and parking
Z

GWARNING
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.
General notes
During a cold start, the engine runs at higherspeeds to enable the catalytic converter toreach its operating temperature. The sound ofthe engine may change during this time.
Automatic transmission
XShift the transmission to position](Ypage 132).The transmission position indicator on themultifunction display shows](Ypage 131).
iYou can start the engine in transmissionpositions]and\\.
Starting procedure with the SmartKey
To start the engine using the SmartKey insteadof the Start/Stop button, pull the Start/Stopbutton out of the ignition lock.
XTurn the SmartKey to positionIin the igni-tion lock (Ypage 123) and release it as soonas the engine is running.
Starting procedure with the Start/Stop
button
The Start/Stop button can be used to start thevehicle manually without inserting the SmartKeyinto the ignition lock. The Start/Stop buttonmust be inserted in the ignition lock and theSmartKey must be in the vehicle. This mode forstarting the engine operates independently ofthe ECO start/stop automatic engine start func-tion.
You can start the engine if a valid SmartKey is inthe vehicle. Switch off the engine and alwaystake the SmartKey with you when leaving the
vehicle, even if you only leave it for a short time.Pay attention to the important safety notes.
XDepress the brake pedal and keep itdepressed.
XPress the Start/Stop button once(Ypage 123).The engine starts.
Starting procedure via smartphone
Observe the important safety notes on startingthe engine (Ypage 124).
You can also start your engine via your smart-phone from outside the vehicle. In this case, thepreviously selected climate control setting isactivated. In this way you can cool or heat theinterior of the vehicle before starting the jour-ney.
Only start the engine via your smartphone if it issafe to start and run the engine where your vehi-cle is parked.
Observe the legal stipulations in the area whereyour vehicle is parked. Engine start via smart-phone may be limited to certain countries orregions.
You can execute a maximum of two consecutivestarting attempts via your smartphone. If youinsert the SmartKey into the ignition lock, youcan carry out two more starting attempts.
Once you have started the engine, you canswitch the engine off via your smartphone at anytime.
You can only start the engine via your smart-phone if:
Rthe SmartKey is in the ignition lock
Rpark position]is selected
Rthe accelerator pedal is not depressed
Rthe alarm for the anti-theft alarm system isnot set
Rthe panic alarm is not activated
Rthe hazard warning lamps are switched off
Rthe hood is closed
Rthe doors are closed and locked
Rthe windows and sliding sunroof are closed
Also make sure that:
Rthe fuel tank is sufficiently filled
Rthe starter battery has been sufficientlycharged
Driving125
Driving and parking
Z

ProblemPossible causes/consequences andPPSolutions
The engine does notstart. You cannot hearthe starter motor.
The on-board voltage is too low because the battery is too weak ordischarged.
XJump-start the vehicle (Ypage 282).
If the engine does not start despite attempts to jump-start it:
XConsult a qualified specialist workshop.
The starter motor was exposed to a thermal load that was too high.
XAllow the starter motor to cool down for approximately two minutes.
XTry to start the engine again.
If the engine still does not start:
XConsult a qualified specialist workshop.
The engine is not runningsmoothly and is misfir-ing.
There is a malfunction in the engine electronics or in a mechanicalcomponent of the engine management system.
XOnly depress the accelerator pedal slightly.Otherwise, non-combusted fuel may get into the catalytic converterand damage it.
XHave the cause rectified immediately at a qualified specialist work-shop.
The coolant temperaturegauge shows a valueabove 248 ‡ (120 †).The coolant warninglamp may also be on anda warning tone maysound.
The coolant level is too low. The coolant is too hot and the engine is nolonger being cooled sufficiently.
XStop as soon as possible and allow the engine and the coolant tocool down.
XCheck the coolant level (Ypage 263). Observe the warning notesas you do so and add coolant if necessary.
Notes on towing vehicles
The vehicle is not suitable for attaching tow barsystems, such as those used for flat towing ordinghy towing.
Attaching or using tow bar systems may result indamage to the vehicle.
When towing a vehicle with tow bar systems,safe driving characteristics cannot be guaran-teed for the towing vehicle or the towed vehicle.
The vehicle/trailer combination may swerve.
Observe the permissible towing methods(Ypage 287) and the notes on towing with bothaxles on the ground (Ypage 286).
DYNAMIC SELECT button (all vehicles
except Mercedes-AMG vehicles)
Use the DYNAMIC SELECT button to change thedrive program. Depending on the drive programselected the following vehicle characteristicswill change:
Rthe drive (engine and transmission manage-ment)
Rthe suspension (vehicles with damping sys-tem or AMG adaptive sport suspension sys-tem)
Rthe sound of the exhaust system (vehicleswith sports exhaust system)
Rthe steering
Rthe availability of the ECO start/stop function
Rthe climate control
Each time you start the engine with the Smart-Key or the Start/Stop button, drive programCis
DYNAMIC SELECT button (all vehicles except Mercedes-AMG vehicles)129
Driving and parking
Z

away carefully to check whether the desiredtransmission position is engaged. Ideally, youshould select transmission position[anddrive programEorS.
Engaging park position P
!If the engine speed is too high or the vehicleis coasting, do not shift the automatic trans-mission directly from[to^, from^to[or directly to]. Otherwise, the automatictransmission may be damaged.
XPush the DIRECT SELECT lever switch in thedirection of arrow].Transmission position display]is shown inthe multifunction display.
When you have engaged park position], makesure that the transmission position displayshows]in the multifunction display.
You can engage park position]only when thevehicle is stationary; do not switch directly topark position]at high engine speed.
Depressing the brake and pushing the DIRECTSELECT lever up or down disengages the park-ing lock. The transmission is in neutral\\.
At transmission fluid temperatures below

Transmission positions
EPark position
This prevents the vehicle from rollingaway when stopped.
Only shift the transmission to posi-tion]when the vehicle is station-ary. The parking lock should not beused as a brake when parking.Always apply the electronic parkingbrake in addition to the parking lockin order to secure the vehicle.
In the event of a malfunction of thevehicle's electronics, the transmis-sion may lock in position]. Havethe vehicle electronics checkedimmediately at a qualified specialistworkshop.
Park position]is automaticallyengaged if:
Ryou switch off the engine using theSmartKey and remove the Smart-Key
Ryou switch off the engine using theSmartKey or using the Start/Stopbutton and open the driver's dooror front-passenger door
Ryou open the driver's door whenthe vehicle is stationary or whendriving at a very low speed and thetransmission is in position[or^
FReverse gear
Only shift the transmission into posi-tion^when the vehicle is station-ary.
DNeutral
Do not shift the transmission to\\while driving. The automatic trans-mission could otherwise be dam-aged.
No power is transmitted from theengine to the drive wheels.
Releasing the brakes will allow you tomove the vehicle freely, e.g. to pushit or tow it.
If ESP®is deactivated or faulty: shiftthe transmission to position\\if thevehicle is in danger of skidding, e.g.on icy roads.
If you switch the engine off with thetransmission in position^or[,the automatic transmission shifts to\\automatically.
!Coasting in neutral\\maycause damage to the drive train.
:Drive
The automatic transmission changesgear automatically. All forward gearsare available.
Driving tips
Changing gear
The automatic transmission shifts through theindividual gears automatically when it is in trans-mission position[. This automatic gear shift-ing behavior is determined by:
Rthe selected drive program
Rthe position of the accelerator pedal
Rthe road speed
Accelerator pedal position
Your style of driving influences how the auto-matic transmission shifts gear:
Rlittle throttle: early upshifts
Rmore throttle: late upshifts
134Automatic transmission
Driving an d parking

Before the engine speed reaches the red area,an upshift indicator will be shown in the multi-function display.
XShift to recommended gearCwhen mes-sageDis shown in the multifunction display.
Kickdown
XFor maximum acceleration, depress theaccelerator pedal beyond the pressure point.The automatic transmission shifts to a lowergear depending on the engine speed.
XShift back up once the desired speed isreached.
During kickdown, you cannot shift gears usingthe steering wheel paddle shifters.
If you apply full throttle, the automatic trans-mission shifts up to the next gear when themaximum engine speed is reached. This pre-vents the engine from overrevving.
Mercedes-AMG vehicles:it is only possible touse kickdown in temporary manual drive pro-gramM. When manual drive programMis per-manently activated, kickdown is not possible.
Problems with the transmission
ProblemPossible causes/consequences andPPSolutions
The transmission hasproblems shifting gear.The transmission is losing oil.
XHave the transmission checked at a qualified specialist workshopimmediately.
The acceleration abilityis deteriorating.
The transmission no lon-ger shifts into all of thegears.
Reverse gear can no lon-ger be engaged.
The transmission is in emergency mode.
XStop the vehicle.
XShift the transmission to position].
XSwitch off the engine.
XWait at least ten seconds before restarting the engine.
XShift the transmission to position[.
XHave the transmission checked at a qualified specialist workshopimmediately.
Refueling
Important safety notes
GWARNING
Fuel is highly flammable. Risk of fire and
explosion by improper handling of fuel.
You must avoid fire, open flames, smoking
and creating sparks. Switch off the ignition
before refueling and, if present, switch off the
auxiliary heating.
GWARNING
Fuel is poisonous and hazardous to health.
There is a risk of injury.
Refueling139
Driving and parking
Z

helps you to avoid overheating the brakes andwearing them out excessively.
When you take advantage of engine braking, itis possible that a drive wheel will not rotate forsome time, e.g. on a slippery road surface.This could cause damage to the drive train.This type of damage is not covered by theMercedes-Benz warranty.
Briefly depressing the accelerator pedal ondownhill gradients while the manual drive pro-gramMis temporarily activated: the automatictransmission may switch to the last active auto-matic drive programEorS. The automatic trans-mission may shift to a higher gear. This canreduce the engine's braking effect.
Heavy and light loads
GWARNING
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 constantlyresults in excessive and premature wear tothe brake pads.
If the brakes have been subjected to a heavyload, do not stop the vehicle immediately. Driveon for a short while. This allows the airflow tocool the brakes more quickly.
Wet roads
If you have driven for a long time in heavy rainwithout braking, there may be a delayed reac-tion from the brakes when braking for the firsttime. This may also occur after the vehicle hasbeen washed or driven through deep water.
You have to depress the brake pedal morefirmly. Maintain a greater distance from thevehicle in front.
After driving on a wet road or having the vehiclewashed, brake firmly while paying attention tothe traffic conditions. This will warm up thebrake discs, thereby drying them more quicklyand protecting them against corrosion.
Limited braking performance on salt-
treated roads
If you drive on salted roads, a layer of salt resi-due may form on the brake discs and brakepads. This can result in a significantly longerbraking distance.
RIn order to prevent any salt build-up, apply thebrakes occasionally while paying attention tothe traffic conditions.
RCarefully depress the brake pedal and thebeginning and end of a journey.
RMaintain a greater distance to the vehicleahead.
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 engine isrunning
Observe additional warning messages in themultifunction display.
The brake fluid level may be too low due tobrake pad wear or leaking brake lines.
Have the brake system checked immediately.Consult a qualified specialist workshop toarrange this.
!A function or performance test should onlybe carried out on a 2-axle dynamometer. Ifyou wish to operate the vehicle on such adynamometer, please consult a qualified spe-cialist workshop in advance. You could oth-erwise damage the drive train or the brakesystem.
!As the ESP®system operates automatically,the engine and the ignition must be switchedoff (the SmartKey must be in position

For this reason, in the event of heavy rain or inconditions in which hydroplaning may occur,you must drive in the following manner:
Rlower your speed
Ravoid ruts
Ravoid sudden steering movements
Rbrake carefully
Driving on flooded roads
!Do not drive through flooded areas. Checkthe depth of any water before driving throughit. Drive slowly through standing water. Oth-erwise, water could enter the vehicle interioror engine compartment. It can then damagethe engine's or automatic transmission'selectronic components. It can also be suckedin by the engine's air intake connection andcause engine damage.
Winter driving
GWARNING
If you shift down on a slippery road surface in
an attempt to increase the engine's braking
effect, the drive wheels could lose their grip.
There is an increased danger of skidding and
accidents.
Do not shift down for additional engine brak-
ing on a slippery road surface.
GDANGER
If the exhaust pipe is blocked or adequate
ventilation is not possible, poisonous gases
such as carbon monoxide (CO) may enter the
vehicle. This is the case, e.g. if the vehicle
becomes trapped in snow. There is a risk of
fatal injury.
If you leave the engine or the auxiliary heating
running, make sure the exhaust pipe and area
around the vehicle are clear of snow. To
ensure an adequate supply of fresh air, open a
window on the side of the vehicle that is not
facing into the wind.
Have your vehicle winter-proofed at a qualifiedspecialist workshop at the onset of winter.
Drive particularly carefully on slippery road sur-faces. Avoid sudden acceleration, steering andbraking maneuvers. Do not use cruise control orActive Distance Assist DISTRONIC.
If the vehicle threatens to skid or cannot bestopped when moving at low speed:
XShift the transmission to position\\.
XTry to bring the vehicle under control usingcorrective steering.
The outside temperature indicator is notdesigned to serve as an ice-warning device andis therefore unsuitable for that purpose.Changes in the outside temperature are dis-played after a short delay.
Indicated temperatures just above the freezingpoint do not guarantee that the road surface isfree of ice. The road may still be icy, especially inwooded areas or on bridges.
You should pay special attention to road condi-tions when temperatures are around freezingpoint.
For more information on driving with snowchains, see (Ypage 293).
For more information on driving with summertires, see (Ypage 292).
Observe the notes in the "Winter operation" sec-tion (Ypage 292).
Driving systems
Cruise control
General notes
Cruise control maintains a constant road speedfor you. It brakes automatically in order to avoidexceeding the set speed. On long and steepdownhill gradients, especially if the vehicle isladen, you must select a low gear in good time.You need to shift manually using the steeringwheel paddle shifters beforehand. By doing so,you will make use of the braking effect of theengine. This relieves the load on the brake sys-tem and prevents the brakes from overheatingand wearing too quickly.
When the engine is running, you can use thecruise control lever to limit the speed to anyspeed between 20 mph (30 km/h) and the tech-nically permitted maximum speed of the vehicle.
Use cruise control if road and traffic conditionsmake it appropriate to maintain a steady speedfor a prolonged period.
150Driving systems
Driving and parking