ignition MERCEDES-BENZ SLC 2019 Repair Manual

Towing and tow-starting
Important safety notes
GWARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissi-
ble gross weight of your vehicle, the:
Rthe towing eye could detach itself
Rthe vehicle/trailer combination could roll-
over.
There is a risk of an accident.
When towing or tow-starting another vehi-
cle, its weight should not be greater than
the permissible gross weight of your vehicle.
Details on the permissible gross vehicle weightof your vehicle can be found on the vehicleidentification plate (Ypage 297).
!When Active Brake Assist, Active DistanceAssist DISTRONIC or the HOLD function isactivated, the vehicle brakes automaticallyin certain situations.
To avoid damage to the vehicle, deactivatethese systems in the following or similar sit-uations:
Rwhen towing the vehicle
Rin the car wash
!Only secure the tow rope or tow bar at thetowing eyes. Otherwise, the vehicle could bedamaged.
!Do not use the towing eye for recovery,this could damage the vehicle. If in doubt,recover the vehicle with a crane.
!When towing, pull away slowly andsmoothly. If the tractive power is too high,the vehicles could be damaged.
!Do not tow with sling-type equipment. Thiscould damage the vehicle.
!When towing away vehicles with KEYLESS-GO, use the key instead of the Start/Stopbutton. The automatic transmission mayotherwise shift to position]when youopen the driver's or front-passenger door,which could damage the transmission.
!Make sure that the electric parking brakeis released. If the electric parking brake isfaulty, visit a qualified specialist workshop.
!You may tow the vehicle for a maximumdistance of 30 miles (50 kilometers). A tow-ing speed of 30 mph (50 km/h) must not beexceeded.
For towing distances over 30 miles(50 kilometers), the entire vehicle must beraised and transported.
!When you are tow-starting or towinganother vehicle, its weight must not exceedthe maximum permissible gross weight ofyour vehicle.
It is better to have the vehicle transportedthan to have it towed away.
The automatic transmission must be in posi-tion\\when the vehicle is being towed away.
The battery must be connected and charged.Otherwise, you:
Rcannot turn the SmartKey to positionHinthe ignition lock
Rcannot shift the automatic transmission toposition\\
Deactivate the automatic locking featurebefore the vehicle is towed (Ypage 178). Youcould otherwise be locked out when pushingor towing the vehicle.
Installing/removing the towing eye
Installing the towing eye
GWARNING
The exhaust tail pipe may be very hot. There
is a risk of burns when removing the rear
cover.
Do not touch the exhaust pipe. Take particu-
lar care when removing the rear cover.
Towing and tow-starting263
Breakdown assistance
Z

The brackets for the screw-in towing eye arelocated in the bumpers. They are at the frontand at the rear, behind the covers.
XRemove the towing eye from the vehicle toolkit (Ypage 252).
XPress the mark on coverCinwards in thedirection of the arrow.
XTake coverCoff the opening.
XScrew in the towing eye clockwise as far asit will go and tighten it.
Removing the towing eye
XUnscrew and remove the towing eye.
XAttach coverCto the bumper and pressuntil it engages.
XPlace the towing eye in the vehicle tool kit.
Towing a vehicle with both axles on
the ground
GWARNING
You can no longer steer the vehicle if the
steering wheel lock has been engaged.
There is a risk of an accident.
Always switch off the ignition when towing
the vehicle with a tow cable or a tow bar.
The automatic transmission shifts to position]automatically when you open the driver'sor front-passenger door or when you removethe SmartKey from the ignition lock.
In order to ensure that the automatic trans-mission stays in position\\when towingaway the vehicle, you must observe the follow-ing points:
XSwitch on the hazard warning lamps(Ypage 99).
XTurn the SmartKey to positionHin the igni-tion lock.
On vehicles with KEYLESS-GO, use theSmartKey instead of the Start/Stop button(Ypage 118).
XDepress and hold the brake pedal.
XShift the transmission to position\\.
XRelease the brake pedal.
XRelease the electric parking brake.
XLeave the SmartKey in positionHin theignition lock.
In order to signal a change of direction whentowing the vehicle with the hazard warninglamps switched on, use the combinationswitch as usual. In this case, only the indicatorlamps for the direction of travel flash. Whenyou reset the combination switch, the hazardwarning flashers start flashing again.
It is important that you observe the safetyinstructions when towing away your vehicle(Ypage 263).
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 atowing bar with both axles on the ground. Donot use any tow bar systems.
Towing the vehicle with the rear axle
raised
!The ignition must be switched off if youare towing the vehicle with the rear axle
raised. Intervention by ESP®could other-wise damage the brake system.
!Vehicles with automatic transmission mustnot be towed with the rear axle raised. Thevehicle/trailer combination may otherwiseswerve or even roll over.
264Towing and tow-starting
Breakdown assistance

XMake sure that the ignition is switched off(Ypage 118).
or
XWhen using the SmartKey, turn the Smart-Key to position

pressure loss warning system" section(Ypage 274).
Important safety notes
The tire pressure warning system does notwarn you of an incorrectly set tire pressure.Observe the notes on the recommended tirepressure (Ypage 270).
The tire pressure loss warning does notreplace the need to regularly check the tirepressure. An even loss of pressure on severaltires at the same time cannot be detected bythe tire pressure loss warning system.
The tire pressure monitor is not able to warnyou of a sudden loss of pressure, e.g. if thetire is penetrated by a foreign object. In theevent of a sudden loss of pressure, bring thevehicle to a halt by braking carefully. Avoidabrupt steering movements.
The function of the tire pressure loss warningsystem is limited or delayed if:
Rsnow chains are mounted on your vehicle'stires.
Rroad conditions are wintry.
Ryou are driving on sand or gravel.
Ryou adopt a very sporty driving style (corner-ing at high speeds or driving with high ratesof acceleration).
Ryou drive with a heavy load.
Restarting the tire pressure loss warn-
ing system
Restart the tire pressure loss warning systemif you have:
Rchanged the tire pressure
Rchanged the wheels or tires
Rmounted new wheels or tires
XBefore restarting, make sure that the tirepressures are set properly on all four tiresfor the respective operating conditions.
The recommended tire pressure can befound on the Tire and Loading Informationplacard on the B-pillar. Additionally, a tirepressure table is attached to the fuel fillerflap. The tire pressure loss warning systemcan only give reliable warnings if you haveset the correct tire pressure. If an incorrect
tire pressure is set, these incorrect valueswill be monitored.
XAlso observe the notes in the section on tirepressures (Ypage 270).
XMake sure that the SmartKey is in positionHin the ignition lock (Ypage 118).
XPress theYorebutton on the steer-ing wheel to select theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPress thevbutton.TheRun Flat Indicator Active PressRun Flat Indicator Active Press'OK' to Restart'OK' to Restartmessage appears in themultifunction display.
If you wish to confirm the restart:
XPress thevbutton.TheTire Pressure Now OK?Tire Pressure Now OK?messageappears in the multifunction display.
XPress thecordbutton to selectYesYes.
XPress thevbutton.TheRun Flat Indicator RestartedRun Flat Indicator Restartedmes-sage appears in the multifunction display.
After a teach-in period, the tire pressureloss warning system will monitor the set tirepressures of all four tires.
If you wish to cancel the restart:
XPress the8button.
or
XIf theTire Pressure Now OK?Tire Pressure Now OK?messageappears, use thecordbutton toselectCancelCancel.
XPress thevbutton.The tire pressure values stored at the lastrestart will continue to be monitored.
Tire pressure monitor
General notes
If a tire pressure monitor is installed, the vehi-cle's wheels have sensors that monitor the tirepressures in all four tires. The tire pressuremonitor warns you if the pressure drops in oneor more of the tires. The tire pressure monitoronly functions if the corresponding sensorsare installed in all wheels.
Information on tire pressures is displayed inthe multifunction display. After a few minutesof driving, the current tire pressure of each tire
274Tire pressure
Wheels and tires

vehicle to a halt by braking carefully. Avoidabrupt steering movements.
The tire pressure monitor has a yellow warninglamp in the instrument cluster for indicatingpressure loss or a malfunction. Whether thewarning lamp flashes or lights up indicateswhether a tire pressure is too low or the tirepressure monitor is malfunctioning:
Rif the warning lamp is lit continuously, thetire pressure on one or more tires is signifi-cantly too low. The tire pressure monitor isnot malfunctioning.
Rif the warning lamp flashes for approx-imately a minute and then remains lit con-stantly, the tire pressure monitor is malfunc-tioning.
In addition to the warning lamp, a messageappears in the multifunction display. Observethe information on display messages(Ypage 201).
It may take up to ten minutes for a malfunc-tion of the tire pressure monitor to be indica-ted. A malfunction will be indicated by the tirepressure warning lamp flashing for approx-imately one minute and then remaining lit.When the malfunction has been rectified, thetire pressure warning lamp goes out after afew minutes of driving.
The tire pressure values indicated by the on-board computer may differ from those meas-ured at a gas station with a pressure gage. Thetire pressures shown by the on-board com-puter refer to those measured at sea level. Athigh altitudes, the tire pressure values indica-ted by a pressure gage are higher than thoseshown by the on-board computer. In this case,do not reduce the tire pressures.
The operation of the tire pressure monitor canbe affected by interference from radio trans-mitting equipment (e.g. radio headphones,two-way radios) that may be being operated inor near the vehicle.
Checking the tire pressure electroni-
cally
XMake sure that the SmartKey is in positionH(Ypage 118) in the ignition lock.
XPress theYorebutton on the steer-ing wheel to select theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPressv.The current tire pressure of each tire isshown in the multifunction display.
If the vehicle has been parked for over20 minutes, theTire pressure will beTire pressure will bedisplayed after driving a few minutesdisplayed after driving a few minutesmessage appears.
After a teach-in process, the tire pressuremonitor automatically detects new wheels ornew sensors. As long as a clear allocation ofthe tire pressure value to the individual wheelsis not possible, theTire Pressure MonitorTire Pressure MonitorActiveActivedisplay message is shown instead ofthe tire pressure display. The tire pressuresare already being monitored.
If an emergency spare wheel is mounted, thesystem may continue to show the tire pressureof the wheel that has been removed for a fewminutes. Be aware that the value displayed forthe position where the emergency spare wheelis fitted is not the same as the current tirepressure of the emergency spare wheel.
Tire pressure monitor warning mes-
sages
The tire pressure monitor detects a pressureloss in one or more tires:
RIf the tire pressure monitor detects a pres-sure loss in one or more tires, a warningmessage is shown in the multifunction dis-play. The yellow tire pressure warning lampthen lights up.
RIf thePlease Correct Tire PressurePlease Correct Tire Pressuremessage appears in the multifunction dis-play, the tire pressure in at least one tire istoo low. The tire pressure must be correctedwhen the opportunity arises.
RIf theCheck TiresCheck Tiresmessage appears in themultifunction display, the tire pressure in atleast one tire has dropped significantly. Thetires must be checked.
RIf theWarning Tire MalfunctionWarning Tire Malfunctionmes-sage appears in the multifunction display,the tire pressure in at least one tire hasdropped suddenly. The tires must bechecked.
Observe the instructions and safety notes inthe display messages in the "Tires" section(Ypage 201).
276Tire pressure
Wheels and tires

If the wheel positions on the vehicle are rota-ted, the tire pressures may be displayed forthe wrong positions for a short time. This isrectified after a few minutes of driving, and thetire pressures are displayed for the correctpositions.
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 thecurrently set tire pressures as the referencevalues for monitoring. In most cases, the tirepressure monitor will automatically detect thenew reference values after you have changedthe tire pressure. However, you can also setreference values manually as described here.The tire pressure monitor then monitors thenew tire pressure values.
XSet the tire pressure to the value recom-mended for the corresponding driving situa-tion on the Tire and Loading Informationplacard on the driver's side B-pillar(Ypage 270).
Additional tire pressure values for differentloads can also be found on the tire pressuretable on the inside of the fuel filler flap(Ypage 270).
XMake sure that the tire pressure is correcton all four wheels.
XEnsure that the SmartKey is in positionHin the ignition lock.
XPress theYorebutton on the steer-ing wheel to select theServ.Serv.menu.
XPress thecordbutton to selectTire PressureTire Pressure.
XPressv.The multifunction display shows the currenttire pressure for the individual tires or theTire pressure will be displayedTire pressure will be displayedafter driving a few minutesafter driving a few minutesmessage.
XPress thedbutton.TheUse Current Pressures as NewUse Current Pressures as NewReference ValuesReference Valuesmessage appears in themultifunction display.
If you wish to confirm the restart:
XPressv.TheTire Press. Monitor RestartedTire Press. Monitor Restartedmessage appears in the multifunction dis-play.
After driving for a few minutes, the systemchecks whether the current tire pressuresare within the specified range. The new tirepressures are then accepted as referencevalues and monitored.
If you wish to cancel the restart:
XPress8.The tire pressure values stored at the lastrestart will continue to be monitored.
Tire pressure277
Wheels and tires
Z

Clean the contact surfaces of the wheel andthe brake disc thoroughly every time a wheelis rotated. Check the tire pressure and, if nec-essary, restart the tire pressure loss warningsystem or the tire pressure monitor.
Direction of rotation
Tires with a specified direction of rotation haveadditional benefits, e.g. if there is a risk ofhydroplaning. These advantages can only begained if the tires are installed correspondingto the direction of rotation.
An arrow on the sidewall of the tire indicatesits correct direction of rotation.
Storing wheels
Store wheels that are not being used in a cool,dry and preferably dark place. Protect the tiresfrom oil, grease, gasoline and diesel.
Mounting a wheel
Preparing the vehicle
XStop the vehicle on solid, non-slippery andlevel ground.
XApply the electric parking brake manually.
XBring the front wheels into the straight-ahead position.
XShift the transmission to position].
XSwitch off the engine.
XVehicles without KEYLESS-GO:removethe SmartKey from the ignition lock.
XVehicles with KEYLESS-GO:open the driv-er's door.The vehicle electronics now have status0.This is the same as the SmartKey havingbeen removed.
XVehicles with KEYLESS-GO:remove theStart/Stop button from the ignition lock(Ypage 118).
XIf included in the vehicle equipment, removethe tire-change tool kit from the vehicle.
XSafeguard the vehicle against rolling away.
iDue to differences in vehicle equipment,not all vehicles are equipped with a tire-change tool kit. For information on which
tools are required to perform a wheelchange on your vehicle, consult an author-ized Mercedes-Benz Center.
Necessary tire-changing tools can include,for example:
RJack
RWheel chock
RLug wrench
Securing the vehicle to prevent it from
rolling away
If your vehicle is equipped with a wheel chock,it can be found in the tire-change tool kit(Ypage 252).
The folding wheel chock is an additional safetymeasure to prevent the vehicle from rollingaway, for example when changing a wheel.
XFold both plates upwardsC.
XFold out lower plateD.
XGuide the lugs on the lower plate fully intothe openings in base plate