2012 MERCEDES-BENZ C-Class SEDAN ECU

Never operate the vehicle with more than one
emergency spare wheel/spare wheel that
differs in size.
Only use an emergency spare wheel/spare
wheel of a differing size briefly and do not
switch off ESP ®
.
When using an emergency spare wheel, you
must not exceed the maximum speed of
50 mph (80 km/h).GWARNING
Have the emergency spare wheel/spare
wheel replaced with a new wheel as soon as
possible at a qualified specialist workshop
which has the necessary specialist knowledge
and tools to carry out the work required.
Mercedes-Benz recommends that you use an
authorized Mercedes-Benz Center for this
purpose. In particular, work relevant to safety
or on safety-related systems must be carried
out at a qualified specialist workshop.
i Vehicles without a spare wheel/
emergency spare wheel are not equipped
with a tire-change tool kit at the factory. For
more information on which tools are
required to perform a wheel change on your
vehicle, e.g. wheel chock, lug wrench or
alignment bolt, consult an authorized
Mercedes-Benz Center.
XPrepare the vehicle as described
( Y page 293).XRemove the following items (depending on
the vehicle's equipment) from the stowage
well under the trunk/trunk floor:
R the emergency spare wheel
R the folding wheel chock
R the lug wrench
R the jackXSecure the vehicle to prevent it from rolling
away.Securing the vehicle to prevent it from
rolling awayGWARNING
Only jack up the vehicle on level ground or on
slight inclines/declines. The vehicle could
otherwise fall off the jack and injure you or
others.
If your vehicle is equipped with a wheel chock,
it can be found in the vehicle tool kit
( Y page 292).
The folding wheel chock is an additional
securing measure to prevent the vehicle from
rolling away, for example when changing a
wheel.
XFold both plates upwards :.XFold out lower plate ;.XGuide the lugs on the lower plate fully into
the openings in base plate =.
Securing the vehicle on level ground
XOn level ground: place chocks or other
suitable items under the front and rear of294Flat tireBreakdown assistance

the wheel that is diagonally opposite the
wheel you wish to change.
Securing the vehicle on slight downhill gradients
XOn downhill gradients: place chocks or
other suitable items in front of the wheels
of the front and rear axle.
Raising the vehicle
GWARNING
When jacking up the vehicle, only use the jack
which has been specifically approved by
Mercedes-Benz for your vehicle.
The jack is designed exclusively for jacking up
the vehicle at the jacking points built into both
sides of the vehicle. The jack saddle must be
placed centrally under the jacking point. The
jack must always be vertical when in use,
especially on inclines or declines.
The jack is intended only for lifting the vehicle
briefly for wheel changes. It is not suited for
performing maintenance work under the
vehicle. To help avoid personal injury, use the
jack only to lift the vehicle during a wheel
change.
Never get beneath the vehicle while it is
supported by the jack. Keep hands and feet
away from the area under the lifted vehicle.
Always lower the vehicle onto sufficient
capacity jackstands before working under the
vehicle.
Always firmly engage the parking brake and
block the wheels with wheel chocks or other
sizable objects before raising the vehicle with
the jack. Do not disengage the parking brake
while the vehicle is raised.
Make sure that the ground on which the
vehicle is standing and where you place the
jack is solid, level and not slippery. If
necessary, use a large underlay. On slippery
surfaces, such as tiled floors, you should use
a non-slip underlay, for example a rubber mat.
Do not use wooden blocks or similar objects
as a jack underlay. Otherwise, the jack may
not be able to achieve its load-bearing
capacity if it is not at its full height.
Never start the engine when the vehicle is
raised.
Also observe the notes on the jack.XUsing lug wrench :, loosen the bolts on
the wheel you wish to change by about one
full turn. Do not unscrew the bolts
completely.
The jacking points are located just behind the
wheel housings of the front wheels and just
in front of the wheel housings of the rear
wheels (arrows).
Flat tire295Breakdown assistanceZ

GWARNING
The jack is designed exclusively for jacking up
the vehicle at the jacking points. The jack
saddle must be placed centrally under the
jacking point.
If you do not position the jack correctly in the
jacking point, the vehicle can fall off the jack
and seriously or fatally injure you or others.
! The jack is designed exclusively for
jacking up the vehicle at the jacking points.
Otherwise, your vehicle could be damaged.
XPosition jack = at jacking point ;.XMake sure that the base of the jack is
positioned directly under the jacking point.XTurn crank ? clockwise until jack = sits
completely on jacking point ; and the
base of the jack lies evenly on the ground.XTurn crank ? until the tire is raised a
maximum of 1.2 inches (3 cm) off the
ground.Removing a wheelXUnscrew the wheel bolts.
! Do not place wheel bolts in sand or on a
dirty surface. The bolt and wheel hub
threads could otherwise be damaged when
you screw them in.
XRemove the wheel.
Mounting a new wheel
GWARNING
Always replace wheel bolts that are damaged
or rusted.
Never apply oil or grease to wheel bolts.
Damaged wheel hub threads should be
repaired immediately. Do not continue to
drive under these circumstances! Contact an
authorized Mercedes-Benz Center or call
Roadside Assistance.
Incorrect wheel bolts or improperly tightened
wheel bolts can cause the wheel to come off.
This could cause an accident. Make sure to
use the correct wheel bolts.
GWARNING
Only use genuine Mercedes-Benz wheel bolts.
Other wheel bolts may come loose.
Do not tighten the wheel bolts when the
vehicle is raised. Otherwise, the vehicle could
fall off the jack.
GWARNING
Make sure to use the original length wheel
bolts when remounting the original wheel
after it has been repaired.
XClean the wheel and wheel hub contact
surfaces.
! To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt.
296Flat tireBreakdown assistance

XPlace the emergency spare wheel on the
wheel hub and push it on.XTighten the wheel bolts until they are
finger-tight.
Lowering the vehicle
XTurn the crank of the jack counter-
clockwise until the vehicle is once again
standing firmly on the ground.XPlace the jack to one side.XTighten the wheel bolts evenly in a
crosswise pattern in the sequence
indicated ( : to A). The tightening torque
must be 96 lb-ft (130 Nm) .GWARNING
Have the tightening torque checked
immediately after a wheel is changed. The
wheels could come loose if they are not
tightened to a torque of 96 lb/ft (130 Nm).
XTurn the jack back to its initial position and
store it together with the rest of the tire-change tool kit in the trunk/cargo
compartment.XTransport the defective wheel in the trunk/
cargo compartment.
or
XDepending on the size of the wheel, you
may also be able to secure the defective
wheel in the spare wheel well. In this case,
you will have to remove the stowage well
casing from the spare wheel well and stow
it securely in the trunk/cargo
compartment.
i USA only: when you are driving with the
emergency spare wheel mounted, the tire
pressure monitoring system cannot
function reliably. Only restart the tire
pressure monitoring system when the
defective wheel has been replaced with a
new wheel.
All wheels mounted must be equipped with
functioning sensors. The defective wheel
should no longer be in the vehicle.
MOExtended tires (tires with run-flat
properties)
MOExtended tires (tires with run-flat
properties) allow you to continue driving your
vehicle even if one or more tires are entirely
deflated.
MOExtended tires may only be used in
conjunction with the activated tire pressure
loss warning system or with the activated tire
pressure monitoring system.
The maximum permissible distance which
can be driven in run-flat mode depends on the
load in the vehicle. You can drive 50 miles
(80 km) if the vehicle is partially laden and
18 miles (30 km) if it is fully laden.
The maximum permissible distance which
can be driven in run-flat mode is counted from
the moment the tire pressure loss warning
appears in the multifunction display.
You must not exceed a maximum speed of
50 mph (80 km/h).
Flat tire297Breakdown assistanceZ

Wear eye protection.Keep children away.Observe this Operator's
Manual.HEnvironmental noteBatteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
and recycled to protect the
environment.Dispose of batteries in an
environmentally friendly
manner. Return discharged
batteries to a qualified
specialist workshop, e.g. an
authorized Mercedes-Benz
Center, or to a special
collection point for old
batteries.GWARNING
Failure to follow these instructions can result
in severe injury or death.
Never lean over batteries while connecting.
You might get injured.
Battery fluid contains sulfuric acid. Do not
allow this fluid to come in contact with eyes,
skin or clothing. In case it does, immediately
flush affected area with water and seek
medical help if necessary.
A battery will also produce hydrogen gas,
which is flammable and explosive. Keep
flames or sparks away from battery, avoid
improper connection of jumper cables,
smoking etc.
GWARNING
Do not place any metal objects on the battery
as this could result in a short circuit.
Use leak-proof batteries only to avoid the risk
of acid burns in the event of an accident.
Take care that you do not become statically
charged, e.g. by wearing synthetic clothing or
rubbing against textiles. For this reason, you
also should not pull or push the battery over
carpets or other synthetic materials.
Never touch the battery first. First, touch the
outside body of the vehicle in order to release
any possible electrostatic charges.
Do not rub the battery with rags or cloths. The
battery could explode if touched due to
electrostatic charge or due to spark
formation.
! Before working on the battery, e.g.
loosening the battery terminals, switch off
the engine and remove the SmartKey from
the ignition. On vehicles with KEYLESS-GO,
make sure that the ignition is switched off.
Check that all the indicator lamps in the
instrument cluster are off. You may
otherwise destroy electronic components,
such as the alternator.
! Like other batteries, the vehicle battery
may discharge over time if you do not use
the vehicle. In this case have the battery
checked at a qualified specialist workshop,
such as an authorized Mercedes-Benz
Center. You can also charge the battery
with a charger recommended by Mercedes-
Benz. Contact an authorized Mercedes-
Benz Center for more information.
The battery and the cover of the positive
terminal clamp must be installed securely
during operation.
i Remove the SmartKey if you park the
vehicle and do not require any electrical
consumers. The vehicle will then use very
little energy, thus conserving battery
power.
Battery299Breakdown assistanceZ

engine is not running. You will need more
force to steer and brake, you may have to
depress the brake pedal with maximum force.
Before towing away, make sure that the
steering can be moved and is not locked.
If you tow or tow-start another vehicle, its
weight must not exceed the maximum
permissible gross vehicle weight of your
vehicle.GWARNING
The vehicle is braked when the HOLD function
or DISTRONIC PLUS is activated. Therefore,
deactivate HOLD and DISTRONIC PLUS if the
vehicle is to be towed.
It is better to have the vehicle transported
than to have it towed.
! You may only tow the vehicle a maximum
distance of 30 miles (50 km). A towing
speed of 30 mph (50 km/h) must not be
exceeded.
For towing distances over 30 miles
(50 km), the vehicle must loaded onto a
transporter.
! Only secure the tow rope or tow bar at the
towing eyes. Otherwise, the vehicle could
be damaged.
! Do not use the towing eye for recovery,
as this could damage the vehicle. If in
doubt, recover the vehicle with a crane.
! When towing, pull away slowly and
smoothly. If the tractive power is too high,
the vehicles could be damaged.
! Do not tow with sling-type equipment.
This could damage the vehicle.
! On vehicles with KEYLESS-GO, use the
SmartKey instead of the Start/Stop
button. Turn the SmartKey to position 2 in
the ignition lock and shift the automatic
transmission to N. Then, turn the SmartKey
back to 0 and leave it in the ignition lock.
The automatic transmission must be in
position N when the vehicle is being towed.
The battery must be connected and charged.
Otherwise, you:
R cannot turn the SmartKey to position 2 in
the ignition lock
R cannot shift the automatic transmission to
position N
Release the selector lever lock manually to
move it out of position P (Y page 149).
i Before the vehicle is towed, switch off the
automatic locking feature (Y page 78). You
could otherwise be locked out when
pushing or towing the vehicle.
Installing/removing the towing eye
Installing the towing eye
XRemove the towing eye from the vehicle
tool kit ( Y page 292).GWARNING
The exhaust tail pipe may be hot. You could
burn yourself if you touch the tail pipe. Be
particularly careful when removing the rear
cover.
The mountings for the removable towing eyes
are located in the bumpers. They are at the
front and at the rear, under the covers.
Towing and tow-starting303Breakdown assistanceZ

XPress the mark on cover : inwards in the
direction of the arrow.XTake cover : off the opening.XScrew the towing eye in clockwise to the
stop and tighten it.
Removing the towing eye
XLoosen the towing eye and unscrew it.XAttach cover : to the bumper and press
until it engages.XPlace the towing eye in the vehicle tool kit.
Towing the vehicle with the rear axle
raised
Only possible on vehicles without
4MATIC.
When towing your vehicle with the rear axle
raised, it is important that you observe the
safety instructions ( Y page 302).
! The ignition must be switched off if you
are towing the vehicle with the rear axle
raised. Intervention by ESP ®
could
otherwise damage the brake system.
XSwitch on the hazard warning lamps
( Y page 109).XTurn the SmartKey to position 0 in the
ignition lock and remove the SmartKey
from the ignition lock.XWhen leaving the vehicle, take the
SmartKey or the KEYLESS-GO key with you.
Towing a vehicle with both axles on
the ground
When having your vehicle towed, observe the
important safety notes ( Y page 302).
GWARNING
The power assistance for the steering and the
brake force booster do not work when the
engine is not running. You will then need
much more effort to brake and steer the
vehicle. Adapt your style of driving
accordingly.XSwitch on the hazard warning lamps
( Y page 109).
i
When towing with the hazard warning
lamps switched on, use the combination
switch as usual to signal a change of
direction. In this case, only the turn signals
for the desired direction flash. When the
combination switch is reset, the hazard
warning lamps start flashing again.
XTurn the SmartKey to position 2 in the
ignition lock.XWhen the vehicle is stationary, depress the
brake pedal and keep it depressed.XShift the automatic transmission to
position N.XRelease the brake pedal.XRelease the parking brake.
Transporting the vehicle
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting
purposes.
XTurn the SmartKey to position 2 in the
ignition lock.XShift the automatic transmission to
position N.
As soon as the vehicle is loaded:
XPrevent the vehicle from rolling away by
applying the parking brake.XMove the selector lever to P.XTurn the SmartKey to position 0 in the
ignition lock and remove the SmartKey
from the ignition lock.XSecure the vehicle.
! Only lash the vehicle down by the wheels
or wheel rims, not by parts of the vehicle
such as axle or steering components.
Otherwise, the vehicle could be damaged.
304Towing and tow-startingBreakdown assistance

dashboard. You could damage the
dashboard or the cover.XTo open: pull out cover : slightly at the
bottom in the direction of arrow =.XPull cover : outwards in the direction of
arrow ; and remove it.XTo close: clip in cover : on the front of
the dashboard.XFold cover : inwards until it engages.
Fuse box in the engine compartment
XMake sure that the windshield wipers are
turned off.GWARNING
Make sure that the windshield wipers are
switched off and that the SmartKey is
removed from the ignition lock before you
open the cover of the fuse box. Otherwise, the
windshield wipers and the wiper rods above
the cover could be set in motion. This could
lead to you or others being injured by the
wiper rods.
XOpen the hood ( Y page 278).XRemove any existing moisture from the
fuse box using a dry cloth.XTake lines ; from the guides.XTo open: open clamps :.XRemove the fuse box cover forwards.
!
Make sure that no moisture can enter the
fuse box when the cover is open.
XTo close: check whether the rubber seal is
lying correctly in the cover.XInsert the cover at the rear of the fuse box
into the retainer.XFold down the cover and close clamps :.XSecure lines ; in the guides.
!
The cover must be seated properly,
otherwise moisture or dirt could impair the
function of the fuses.
XClose the hood ( Y page 279).
Fuse box in the trunk
XOpen the trunk lid ( Y page 80).306FusesBreakdown assistance