ECU MERCEDES-BENZ CLA 2019 Repair Manual

Permitted towing methods
Mercedes-Benz recommends transporting yourvehicle in the case of a breakdown, rather thantowing it away.
When towing away, use a towing rope or a tow-ing bar with both axles on the ground. Do not useany tow bar systems.
Transporting the vehicle
Vehicles with automatic transmission
!When the vehicle is loaded for transport, thefront and rear axles must be stationary and onthe same transportation vehicle. Positioningover the connection point of the transportvehicle is not permitted. The drive train mayotherwise be damaged.
All vehicles
!You may only secure the vehicle by thewheels, not by parts of the vehicle such asaxle or steering components. Otherwise, thevehicle could be damaged.
XTurn the SmartKey to positionHin the igni-tion lock (Ypage 123).
XShift the transmission to position\\.
As soon as the vehicle has been loaded:
XPrevent the vehicle from rolling away byapplying the electric parking brake.
XShift the transmission to position].
XTurn the SmartKey to positionZin the igni-tion lock and remove it.
XSecure the vehicle.
The towing eye can be used to pull the vehicleonto a trailer or transporter for transporting pur-poses.
Notes on 4MATIC vehicles
!Vehicles with 4MATIC must not be towedwith either the front or the rear axle raised, asdoing so will damage the transmission.
Vehicles with 4MATIC may only either be towedaway with both axles on the ground or be loadedup and transported.
If the vehicle's transmission, front, or rear axle isdamaged, have the vehicle transported on atruck or trailer.
In the event of damage to the electrical sys-tem:
If the battery is defective, the automatic trans-mission will be locked in position]. To shift theautomatic transmission to position\\, youmust provide power to the vehicle's on-boardelectrical system in the same way as when jump-starting (Ypage 282).
Have the vehicle transported on a transporter ortrailer.
Tow-starting (emergency engine
starting)
!Vehicles with automatic transmission mustnot be tow-started. You could otherwise dam-age the automatic transmission.
iYou can find information on "Jump-starting"under (Ypage 282).
Fuses
Important safety notes
GWARNING
If you manipulate or bridge a faulty fuse or if
you replace it with a fuse with a higher amper-
age, the electric cables could be overloaded.
This could result in a fire. There is a risk of an
accident and injury.
Always replace faulty fuses with the specified
new fuses having the correct amperage.
!Only use fuses that have been approved forMercedes-Benz vehicles and which have thecorrect fuse rating for the system concerned.Only use fuses marked with an "S". Other-
Fuses287
Breakdown assistance
Z

wise, components or systems could be dam-aged.
!Make sure that no moisture can enter thefuse box when the cover is open.
!When closing the cover, make sure that it islying correctly on the fuse box. Moisture seep-ing in or dirt could otherwise impair the oper-ation of the fuses.
The fuses in your vehicle serve to close downfaulty circuits. If a fuse blows, all the compo-nents on the circuit and their functions stopoperating.
Blown fuses must be replaced with fuses of thesame rating, which you can recognize by thecolor and value. The fuse ratings are listed in thefuse allocation chart.
The fuse allocation chart is in the fuse box in thefront-passenger footwell (Ypage 289).
If a newly inserted fuse also blows, have thecause traced and rectified at a qualified special-ist workshop, e.g. an authorized Mercedes-BenzCenter.
Before changing a fuse
XSecure the vehicle against rolling away(Ypage 142).
XSwitch off all electrical consumers.
XVehicles without KEYLESS-GO:remove theSmartKey from the ignition lock.
XVehicles with KEYLESS-GO start-functionor KEYLESS-GO:open the driver's door.The vehicle electronics are now in positionZ. This corresponds to the SmartKey beingremoved from the ignition.
The fuses are located in various fuse boxes:
RFuse box in the engine compartment on theleft-hand side of the vehicle, when viewed inthe direction of travel
RFuse box in the front-passenger footwell
The fuse allocation chart is on the fuse box in thefront-passenger footwell (Ypage 289).
Fuse box in the engine compartment
GWARNING
When the hood is open and the windshield
wipers are set in motion, you can be injured by
the wiper linkage. There is a risk of injury.
Always switch off the windshield wipers and
the ignition before opening the hood.
XOpen the hood.
XUse a dry cloth to remove any moisture fromthe fuse box.
XTo open:open clampsD.
XFold up coverCin the direction of the arrowand remove it.
XTo close:check whether the seal is lying cor-rectly in coverC.
XInsert coverCat the back into openings

Rwear excessively and/or unevenly
Rhave an adverse effect on fuel consumption
Overinflated tires
GWARNING
Tires with excessively high pressure can burst
because they are damaged more easily by
road debris, potholes etc. In addition, they
also suffer from irregular wear, which can
severely impair the braking properties and the
driving characteristics. There is a risk of an
accident.
Avoid tire pressures that are too high in all the
tires, including the spare wheel.
Overinflated tires may:
Rincrease the braking distance
Radversely affect handling
Rwear excessively and/or unevenly
Rhave an adverse effect on ride comfort
Rbe more susceptible to damage
Maximum tire pressures
CExample: maximum permissible tire pres-sure
Never exceed the maximum permissible tireinflation pressure. Always observe the recom-mended tire pressure for your vehicle whenadjusting the tire pressure (Ypage 293).
iThe actual values for tires are vehicle-spe-cific and may deviate from the values in theillustration.
Checking the tire pressures
Important safety notes
The tire pressure monitor does not warn you of:
Rincorrectly set tire pressure
Rsudden loss of tire pressure, e.g. from a for-eign object that has penetrated the tire
Observe the notes on tire pressure(Ypage 293).
Information on air pressure for the tires on yourvehicle can be found:
Ron the vehicle's Tire and Loading Informationplacard on the B-pillar
Rin the tire pressure table in the fuel filler flap(Ypage 141)
Rin the "Tire pressure" section
Checking tire pressures manually
To determine and set the correct tire pressure,proceed as follows:
XRemove the valve cap of the tire that is to bechecked.
XPress the tire pressure gauge securely ontothe valve.
XRead the tire pressure and compare it to therecommended value on the Tire and LoadingInformation placard or the tire pressure table(Ypage 293).
XIf the tire pressure is too low, increase the tirepressure to the recommended value.
XIf the tire pressure is too high, release air. Todo so, press down the metal pin in the valve,using the tip of a pen for example. Then checkthe tire pressure again using the tire pressurechecker.
XScrew the valve cap onto the valve.
XRepeat these steps for the other tires.
Tire pressure loss warning system
(Canada only)
General notes
While the vehicle is in motion, the tire pressureloss warning system monitors the set tire pres-sure using the rotational speed of the wheels.This enables the system to detect significantpressure loss in a tire. If the speed of rotation ofa wheel changes as a result of a loss of pressure,
296Tire pressure
Wheels and tires

Restarting the tire pressure monitor
When you restart the tire pressure monitor, allexisting warning messages are deleted and thewarning lamps go out. The monitor uses the cur-rently set tire pressures as the reference valuesfor monitoring. In most cases, the tire pressuremonitor will automatically detect the new refer-ence values after you have changed the tirepressure. However, you can also set referencevalues manually as described here. The tirepressure monitor then monitors the new tirepressure values.
XSet the tire pressure to the value recommen-ded for the corresponding driving situation onthe Tire and Loading Information placard onthe driver's side B-pillar (Ypage 293).
You can find more tire pressure values forvarious operating conditions in the tire pres-sure table inside the fuel filler flap(Ypage 141).
XMake sure that the tire pressure is correct onall four wheels.
XMake sure that the SmartKey is in positionHin the ignition lock (Ypage 123).
XPressYoreon the steering wheel toselect theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPress thevbutton.The multifunction display shows the currenttire pressure for each tire or theTire pres‐Tire pres‐suresurewillwillbebedisplayeddisplayedafterafterdrivingdrivinga few minutesa few minutesmessage.
XPress thedbutton.The multifunction display shows theUseUseCurrent Pressures as New ReferenceCurrent Pressures as New ReferenceValuesValuesmessage.
If you wish to confirm the restart:
XPress thevbutton.TheTireTirePress.Press.MonitorMonitorRestartedRestartedmes-sage appears in the multifunction display.
After driving for a few minutes, the systemchecks whether the current tire pressures arewithin the specified range. The new tire pres-sures are then accepted as reference valuesand monitored.
If you wish to cancel the restart:
XPress the8button.The tire pressure values stored at the lastrestart will continue to be monitored.
Radio type approval for the tire pres-
sure monitor
CountryRadio type approval number
USAFCC ID: MRXMW2433A
FCCIC ID:MRXGG4 This devicecomplies with part 15 of the FCCrules and with license exemptRSS standards of Industry Can-ada. Operation is subject to thefollowing conditions. (1) Thisdevice may not cause harmfulinterference, and (2) This devicemust accept any interferencereceived, including interferencethat may cause undesired oper-ation. Le present appareil estconforme d'industrie Canadaapplicables aux appareils radioexempts de licence. L'exploita-tion est authorisee aux deux con-ditions suivantes. (1). L'appareilne doit pas produire de brouil-lage, et (2) L'autisateur de l'ap-pareil doit accepter tout brouil-lage radioelectrique subi, memesi le brouillage est susceptibled'en compromettre le fonc-tionnement. WARNING: Changesor modifications not expressivelyapproved by the party responsi-ble for compliance could void theusers authority to operate theequipment. The term "IC:" beforethe radio certification numberonly signifies Canada technicalspecifications were met.
FCC ID:MRXMC34MA4 Thisdevice complies with part 15 ofthe FCC rules and with licenseexempt RSS standards of Indus-try Canada. Operation is subjectto the following conditions. (1)This device may not cause harm-ful interference, and (2) Thisdevice must accept any interfer-ence received, including interfer-ence that may cause undesiredoperation. Le present appareilest conforme d'industrie Canadaapplicables aux appareils radioexempts de license. L'exploita-tion est authorisee aux deux con-ditions suivantes. (1). L'appareil
300Tire pressure
Wheels and tires

PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratio
Relationship between tire height and tire widthin percent.
Tire pressure
This is pressure inside the tire applying an out-ward force to each square inch of the tire's sur-face. The tire pressure is specified in pounds persquare inch (psi), in kilopascal (kPa) or in bar.The tire pressure should only be corrected whenthe tires are cold.
Cold tire pressure
The tires are cold:
Rif the vehicle has been parked with the tiresout of direct sunlight for at least three hoursand
Rif the vehicle has not been driven further than1 mile (1.6 km)
Tread
The part of the tire that comes into contact withthe road.
Bead
The tire bead ensures that the tire sits securelyon the wheel. There are several steel wires in thebead to prevent the tire from coming loose fromthe wheel rim.
Sidewall
The part of the tire between the tread and thebead.
Weight of optional extras
The combined weight of those optional extrasthat weigh more than the replaced standardparts and more than 2.3 kg (5 lbs). Theseoptional extras, such as high-performancebrakes, level control, a roof rack or a high-per-formance battery, are not included in the curbweight and the weight of the accessories.
TIN (Tire Identification Number)
This is a unique identifier which can be used bya tire manufacturer to identify tires, for examplefor a product recall, and thus identify the pur-chasers. The TIN is made up of the manufactur-er's identity code, tire size, tire type code andthe manufacturing date.
Load bearing index
The load bearing index (also load index) is a codethat contains the maximum load bearing capa-city of a tire.
Traction
Traction is the result of friction between the tiresand the road surface.
Treadwear indicators
Narrow bars (tread wear bars) that are distrib-uted over the tire tread. If the tire tread is levelwith the bars, the wear limit of

Securing the vehicle to prevent it from
rolling away
If your vehicle is equipped with a wheel chock, itcan be found in the tire-change tool kit(Ypage 274).
The folding wheel chock is an additional safetymeasure to prevent the vehicle from rollingaway, for example when changing a wheel.
XFold both plates upC.
XFold out lower plateD.
XGuide the lugs on the lower plate fully into theopenings in base plate

bolts to come loose. As a result, you could
lose a wheel while driving. There is a risk of
accident.
Never oil or grease wheel bolts. In the event of
damage to the threads, contact a qualified
specialist workshop immediately. Have the
damaged wheel bolts or hub threads
replaced/renewed. Do not continue driving.
GWARNING
If you tighten the wheel bolts or wheel nuts
when the vehicle is raised, the jack could tip
over. There is a risk of injury.
Only tighten the wheel bolts or wheel nuts
when the vehicle is on the ground.
Always pay attention to the instructions andsafety notes in the "Changing a wheel" section(Ypage 310).
Only use wheel bolts that have been designedfor the wheel and the vehicle. For safety rea-sons, Mercedes-Benz recommends that youonly use wheel bolts which have been approvedfor Mercedes-Benz vehicles and the respectivewheel.
!To prevent damage to the paintwork, holdthe wheel securely against the wheel hubwhile screwing in the first wheel bolt.
XClean the wheel and wheel hub contact sur-faces.
XPlace the new wheel on the wheel hub andpush it on.
XTighten the wheel bolts until they are finger-tight.
Lowering the vehicle
GWARNING
The wheels could work loose if the wheel nuts
and bolts are not tightened to the specified
tightening torque. There is a risk of accident.
Have the tightening torque immediately
checked at a qualified specialist workshop
after a wheel is changed.
XPlace the ratchet wrench onto the hexagonnut of the jack so that the lettersABare visi-ble.
XTurn the ratchet wrench until the vehicle isonce again standing firmly on the ground.
XPlace the jack to one side.
XTighten the wheel bolts evenly in a crosswisepattern in the sequence indicated (Cto

Rdo not switch ESP®off.
Rhave a spare wheel or emergency spare
wheel of a different size replaced at the
nearest qualified specialist workshop.
Observe that the wheel and tire dimensions
as well as the tire type must be correct.
When using an emergency spare wheel or sparewheel of a different size, you must not exceedthe vehicle's maximum design speed of 50 mph(80 km/h).
You should regularly check the pressure of theemergency spare wheel, particularly prior tolong trips, and correct the pressure as neces-sary (Ypage 293). The value on the wheel isvalid.
Snow chains must not be mounted on emer-gency spare wheels.
General notes
You can ask for information regarding permittedemergency spare wheels at an authorizedMercedes-Benz Center.
An emergency spare wheel may also be moun-ted against the direction of rotation. Observethe time restriction on use as well as the speedlimitation specified on the emergency sparewheel.
Replace the tires after six years at the latest,regardless of wear. This also applies to theemergency spare wheel.
Tire pressure loss warning system (Canadaonly):as long as you are driving with the emer-gency spare wheel mounted, the tire pressureloss warning system cannot function reliably.Only restart the tire pressure loss warning sys-tem when the defective wheel has beenreplaced with a new wheel.
Vehicles with tire pressure monitor (USAonly):after an emergency spare wheel has beenmounted, the system may still display the tirepressure of the removed wheel for a fewminutes. The value displayed for the mountedemergency spare wheel is not the same as thecurrent tire pressure of the emergency sparewheel.
Removing the emergency spare wheel
Vehicles with the "Minispare" emergency sparewheel
The "Minispare" emergency spare wheel issecured in emergency spare wheel bagCin thetrunk.
XOpen the trunk lid
XRelease securing strapsDon emergencyspare wheel bagC.
XRemove emergency spare wheel bagCwiththe "Minispare" emergency spare wheel.
XOpen emergency spare wheel bagCandremove the "Minispare" emergency sparewheel.
Observe the instructions and safety notes in the"Changing a wheel" section (Ypage 311).
316Emergency spare wheel
Wheels and tires