2019 MERCEDES-BENZ AMG GT ROADSTER light

for further information and availability. Read the
battery charger's operating instructions before
charging the battery.
Do not charge a battery which has been
removed at low temperatures with a battery
charger. Allow the battery to warm up gently
first, if necessary. Otherwise, the service life can be shortened and the starting characteristics
impaired, especially at low temperatures. Replacing the 12 V battery
Observe the notes on the 12 V battery
(Y page 254).
Mercedes-Benz recommends that you have the
12 V battery replaced at a qualified specialist
workshop, e.g. at an authorized Mercedes-Benz
Center.
If you want to replace the battery yourself,
observe the following notes:
R Always replace a defective battery with a bat-
tery which meets the specific requirements of
the vehicle. The vehicle is equipped with an AGM (Absorb-
ent Glass Mat) technology battery or a lith-
ium-ion battery. Full vehicle functionality is
only guaranteed with an AGM or lithium-ion
battery. For safety reasons, Mercedes-Benz
recommends that you only use batteries
which have been tested and approved for yourvehicle by Mercedes-Benz.
R Use detachable parts such as breather hoses,
angled connecting pieces or terminal covers
from the battery which is to be replaced.
R Make sure that the vent hose is always con-
nected to the original opening on the battery
side.
Install any existing or supplied stop plugs.
Otherwise, gases or battery acid could
escape.
R Make sure that the detachable parts are con-
nected again in the same way. Jump-starting
X For the jump-starting procedure, use only the jump-starting connection point in the engine com-
partment, consisting of a positive terminal and a ground point.
! Avoid repeated and lengthy starting attempts. Otherwise, the catalytic converter could be
damaged by the non-combusted fuel.
X Do not start the vehicle using a rapid charging device.
If your vehicle's battery is discharged, the engine can be jump-started from another vehicle or
from a donor battery using jumper cables.
The battery is not accessible in all vehicles. If the other vehicle's battery is not accessible, jump-start the vehicle using a donor battery or a jump-starting device.
Observe the following during the jump-starting procedure:
R the jumper cables must not come into contact with parts that can move when the engine is
running, such as the V-belt pulley or the fan.
R non-insulated parts of the terminal clamps must not come into contact with other metal parts
while the jumper cables are connected to the battery and the jump-starting connection point.
R only use jumper cables that are not damaged and have a sufficient cross-section and insulated
terminal clamps.
R jump-starting may be performed only using batteries with a nominal voltage of 12 V.
R you may only jump-start the vehicle when the engine and exhaust system are cold.
R the vehicles must not touch each other.
R If the battery is fully discharged, leave the battery that is being used to jump-start connected for
a few minutes before attempting to start. This charges the battery slightly. 256
Jump-startingBreakdown assistance

X
Start the engine of your own vehicle.
X Let the engines run for several minutes.
X Before disconnecting the jumper cables, switch on an electrical consumer in your own vehicle,
e.g. the rear window heating or the lighting.
X When the jump-starting procedure is finished: first, remove the jumper cables from ground
point 0085and from negative terminal 0087of the donor battery, and then from positive terminal 0043
and positive terminal 0044of the donor battery. Begin each time at the contacts on your own vehicle
first.
X After removing the jumper cables, close cover 0083of positive terminal 0043.
X Only for vehicles with a carbon-fiber engine cover: insert the cover of the jump-starting
connection point. Make sure all mountings for the fasteners are positioned precisely behind the corresponding recesses in the cover.
Press the fasteners into the mountings. Turn the fasteners by 00C4of a turn to engage.
X Have the battery checked at a qualified specialist workshop.
Jump-starting is not considered to be a normal operating condition.
i Jumper cables and further information regarding jump-starting can be obtained at a qualified
specialist workshop. Towing and tow-starting
Important safety notes
G
WARNING
The rear axle locks when:
R the engine is not running
R the engine stalls while the vehicle is being
towed
R there is a malfunction in the power supply
or the vehicle's electrical system
There is a risk of an accident.
In the event of a breakdown, you should
always have the vehicle transported. G
WARNING
If the brake system or power steering is mal-
functioning and your vehicle is then towed
away, significantly more effort may be
required to steer and brake than is normally
required. There is a risk of an accident.
In such cases, use a tow bar. Before towing,
make sure that the steering moves freely. G
WARNING
When towing or tow-starting another vehicle
and its weight is greater than the permissible gross weight of your vehicle, the:
R the towing eye could detach itself
R the vehicle/trailer combination could roll-
over.
There is a risk of an accident.
When towing or tow-starting another vehicle,
its weight should not be greater than the per- missible gross weight of your vehicle.
Details on the permissible gross vehicle weight
of your vehicle can be found on the vehicle iden-
tification plate (Y page 287).
! Use the SmartKey instead of the Start/Stop
button when towing the vehicle.
Start the engine and keep it running. The
SmartKey is in position 0048in the ignition lock.
Set the transmission to 005Cusing the E-
SELECT selector lever. Make sure that you
then leave the SmartKey in position 0048.
Check the transmission position in the instru-
ment cluster.
! Make sure that the electric parking brake is
released. If the electric parking brake is faulty,
visit a qualified specialist workshop. 258
Towing and tow-startingBreakdown assistance

If the tire pressures have been set to the lower
values for lighter loads and/or lower road
speeds, the pressures should be reset to the
higher values:
R if you want to drive with an increased load
and/or
R if you want to drive at higher road speeds
The tire pressures for increased loads and/or
higher road speeds, shown in the tire pressure
table, may have a negative effect on driving
comfort.
If the tire pressure is not set correctly, this can
lead to an excessive build-up of heat and a sud-
den loss of pressure.
For more information, contact a qualified spe-
cialist workshop. Important notes on tire pressure
G
WARNING
If the tire pressure drops repeatedly, the
wheel, valve or tire may be damaged. Tire
pressure that is too low may result in a tire
blow-out. There is a risk of an accident. R Check the tire for foreign objects.
R Check whether the wheel is losing air or the
valve is leaking.
If you are unable to rectify the damage, con-
tact a qualified specialist workshop. G
WARNING
If you fit unsuitable accessories onto tire
valves, the tire valves may be overloaded and malfunction, which can cause tire pressure
loss. Due to their design, retrofitted tire pres- sure monitors keep the tire valve open. This
can also result in tire pressure loss. There is a
risk of an accident.
Only screw the standard valve cap or other
valve caps approved by Mercedes-Benz for
your vehicle onto the tire valve.
Use a suitable pressure gauge to check the tire
pressure. The outer appearance of a tire does
not permit any reliable conclusion about the tire pressure. On vehicles equipped with the elec-
tronic tire pressure monitor, the tire pressure
can be checked in the on-board computer.
The tire temperature and pressure increase
when the vehicle is in motion. This is dependent
on the driving speed and the load.
Therefore, you should only correct tire pres-
sures when the tires are cold.
The tires are cold:
R if the vehicle has been parked with the tires
out of direct sunlight for at least three hours
and
R if the vehicle has not been driven further than
1 mile (1.6 km)
The tire temperature changes depending on the
outside temperature, the vehicle speed and the
tire load. If the tire temperature changes by
18 ‡ (10 †), the tire pressure changes by
approximately 10 kPa (0.1 bar/1.5 psi). Take
this into account when checking the pressure of
warm tires. Only correct the tire pressure if it is too low for the current operating conditions. If
you check the tire pressure when the tires are
warm, the resulting value will be higher than if
the tires were cold. This is normal. Do not
reduce the tire pressure to the value specified
for cold tires. The tire pressure would otherwise
be too low.
Observe the recommended tire pressures for
cold tires:
R on the Tire and Loading Information placard
on the B-pillar on the driver's side
R in the tire pressure table in the fuel filler flap
(Y page 126). Tire pressure
267Wheels and tires Z

X
If the tire pressure is too low, increase the tire
pressure to the recommended value.
X If the tire pressure is too high, release air. To
do so, press down the metal pin in the valve,
using the tip of a pen for example. Then check the tire pressure again using the tire pressure
checker.
X Screw the valve cap onto the valve.
X Repeat these steps for the other tires. Tire pressure monitor
General notes If a tire pressure monitor is installed, the vehi-
cle's wheels have sensors that monitor the tire
pressures in all four tires. The tire pressure mon-
itor warns you if the pressure drops in one or
more of the tires. The tire pressure monitor only functions if the corresponding sensors are
installed in all wheels.
Information on tire pressures is displayed in the
multifunction display. After a few minutes of
driving, the current tire pressure of each tire is
shown in the Service
Service menu of the multifunction
display; see illustration (example). For information on the message display, refer to
the "Checking the tire pressure electronically"
section (Y page 270).
Important safety notes G
WARNING
Each tire, including the spare (if provided),
should be checked at least once every two
weeks when cold and inflated to the pressure recommended by the vehicle manufacturer
on the Tire and Loading Information placard on the driver's door B-pillar or the tire pres-
sure label on the inside of the fuel filler flap. If your vehicle has tires of a different size than
the size indicated on the Tire and Loading
Information placard or, if available, the tire
pressure label, you should determine the
proper tire pressure for those tires.
As an added safety feature, your vehicle has
been equipped with a tire pressure monitoring system (TPMS) that illuminates a low tire pres-
sure telltale when one or more of your tires
are significantly underinflated. Accordingly,
when the low tire pressure telltale lights up,
you should stop and check your tires as soon
as possible, and inflate them to the proper
pressure. Driving on a significantly underin-
flated tire causes the tire to overheat and can
lead to tire failure.
Underinflation also reduces fuel efficiency
and tire tread life, and may affect the vehicle's handling and stopping ability. Please note that
the TPMS is not a substitute for proper tire
maintenance, and it is the driver's responsi-
bility to maintain correct tire pressure, even if underinflation has not reached the level to
trigger illumination of the TPMS low tire pres-
sure telltale.
Your vehicle has also been equipped with a
TPMS malfunction indicator to indicate when
the system is not operating properly. The
TPMS malfunction indicator is combined with
the low tire pressure telltale. When the sys-
tem detects a malfunction, the warning lamp
will flash for approximately a minute and then remain continuously illuminated. This
sequence will be repeated every time the vehi-
cle is started as long as the malfunction
exists. When the malfunction indicator is illu- minated, the system may not be able to detect
or signal low tire pressure as intended.
TPMS malfunctions may occur for a variety of reasons, including the installation of incom-
patible replacement or alternate tires or
wheels on the vehicle that prevent the TPMS
from functioning properly. Always check the
TPMS malfunction telltale after replacing one
or more tires or wheels on your vehicle to Tire pressure
269Wheels and tires
Z

ensure that the replacement or alternate Tires
and wheels allow the TPMS to continue to
function properly.
It is the driver's responsibility to set the tire
pressure to that recommended for cold tires
which is suitable for the operating situation
(Y page 266). Note that the correct tire pressure
for the current operating situation must first be taught-in to the tire pressure monitor. If a sub-
stantial loss of pressure occurs, the warning
threshold for the warning message is aligned tothe taught-in reference values. Restart the tire
pressure monitor after adjusting the pressure of
the cold tires (Y page 271). The current pres-
sures are saved as new reference values. As a
result, a warning message will appear if the tire pressure drops significantly.
The tire pressure monitor does not warn you of
an incorrectly set tire pressure. Observe the
notes on the recommended tire pressure
(Y page 266).
The tire pressure monitor is not able to warn you of a sudden loss of pressure, e.g. if the tire is
penetrated by a foreign object. In the event of a
sudden loss of pressure, bring the vehicle to a
halt by braking carefully. Avoid abrupt steering
movements.
The tire pressure monitor has a yellow warning
lamp in the instrument cluster for indicating
pressure loss or a malfunction. Whether the
warning lamp flashes or lights up indicates
whether a tire pressure is too low or the tire
pressure monitor is malfunctioning:
R if the warning lamp is lit continuously, the tire
pressure on one or more tires is significantly
too low. The tire pressure monitor is not mal-
functioning.
R if the warning lamp flashes for around a
minute and then remains lit constantly, the
tire pressure monitor is malfunctioning.
In addition to the warning lamp, a message
appears in the multifunction display. Observe
the information on display messages
(Y page 192).
It may take up to ten minutes for a malfunction
of the tire pressure monitor to be indicated. A
malfunction will be indicated by the tire pres-
sure warning lamp flashing for approximately
one minute and then remaining lit. When the
malfunction has been rectified, the tire pressure warning lamp goes out after a few 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. The
tire pressures shown by the on-board computer
refer to those measured at sea level. At high
altitudes, the tire pressure values indicated by a pressure gage are higher than those shown by
the on-board computer. In this case, do not
reduce the tire pressures.
The operation of the tire pressure monitor can
be affected by interference from radio transmit-
ting equipment (e.g. radio headphones, two-way radios) that may be being operated in or near the vehicle.
Checking the tire pressure electroni-
cally X
Switch on the ignition (Y page 111).
X Press 00E2on the steering wheel to call up
the list of menus.
X Press 0063or0064 on the steering wheel to
select the Service Servicemenu.
X Press 0076.
X Press 0063or0064 to select Tire Pres‐
Tire Pres‐
sure
sure.
X Press 0076.
The current tire pressure of each tire is shown in the multifunction display.
If the vehicle was parked for longer than
20 minutes, the Tire pressure will be Tire pressure will be
displayed after driving a few minutes displayed after driving a few minutes
message appears.
After a teach-in process, the tire pressure mon-
itor automatically detects new wheels or new
sensors. As long as a clear allocation of the tire
pressure value to the individual wheels is not
possible, the Tire TirePressure Pressure Monitor
MonitorActive
Active
message is shown instead of the tire pressure
display. The tire pressures are already being
monitored.
Tire pressure monitor warning mes-
sages If the tire pressure monitor detects a pressure
loss in one or more tires, a warning message is
shown in the multifunction display. The yellow
tire pressure warning lamp then lights up.
R If the Please Correct Tire Pressure Please Correct Tire Pressure
message appears in the multifunction display,
the tire pressure in at least one tire is too low. 270
Tire pressureWheels and tires

Tire labeling
Overview 0043
Uniform Tire Quality Grading Standard
(Y page 279)
0044 DOT, Tire Identification Number
(Ypage 278)
0087 Maximum tire load (Y page 278)
0085 Maximum tire pressure (Y page 268)
0083 Manufacturer
0084 Tire material (Y page 279)
006B Tire size designation, load-bearing capacity
and speed rating (Y page 276)
006C Load index (Y page 278)
006D Tire name
The markings described above are on the tire in
addition to the tire name (sales designation) and the manufacturer's name.
i Tire data is vehicle-specific and may deviate
from the data in the example.
Tire size designation, load-bearing
capacity and speed rating G
WARNING
Exceeding the stated tire load-bearing capa-
city and the approved maximum speed could
lead to tire damage or the tire bursting. There is a risk of accident.
Therefore, only use tire types and sizes
approved for your vehicle model. Observe the tire load rating and speed rating required for
your vehicle. 0043
Tire width
0044 Nominal aspect ratio in %
0087 Tire code
0085 Rim diameter
0083 Load bearing index
0084 Speed rating
General: depending on the manufacturer's
standards, the size imprinted in the tire wall may not contain any letters or may contain one letterthat precedes the size description.
If there is no letter preceding the size descrip-
tion (as shown above): these are passenger
vehicle tires according to European manufac-
turing standards.
If "P" precedes the size description: these are
passenger vehicle tires according to U.S. man-
ufacturing standards.
If "LT" precedes the size description: these are
light truck tires according to U.S. manufacturing standards.
If "T" precedes the size description: compact
emergency wheels with high tire pressure that
are only designed for temporary use in an emer-
gency.
Tire width: tire width0043shows the nominal tire
width in millimeters.
Height-width ratio: aspect ratio0044is the size
ratio between the tire height and tire width and is shown in percent. The aspect ratio is calcula-ted by dividing the tire width by the tire height.
Tire code: tire code0087specifies the tire type.
"R" represents radial tires; "D" represents diag-
onal tires; "B" represents diagonal radial tires.
Optionally, tires with a maximum design speed
of over 149 mph (240 km/h) may have "ZR" in 276
All about
wheels and tiresWheels and tires

The speed rating of tires mounted at the factory
may be higher than the maximum design speed permitted by the electronic speed limiter.
Make sure that your tires have the required
speed rating, e.g. when buying new tires. The
required speed rating for your vehicle can be
found in the "Tires" section (Y page 285).
Further information about reading tire data can
be obtained from any qualified specialist work-
shop.
Load index In addition to the load-bearing index, load
index
0043may also be imprinted on the sidewall
of the tire. You will find this after the letter that identifies the speed rating (Y page 276).
R If no specification is given: no text (as in the
example above), represents a standard load
(SL) tire
R XL or Extra Load: represents a reinforced tire
R Light Load: represents a light load tire
R C, D, E: represents a load range that depends
on the maximum load that the tire can carry at a certain pressure
i Tire data is vehicle-specific and may deviate
from the data in the example. Maximum load rating Maximum tire load
0043is the maximum permis-
sible weight for which the tire is approved.
Do not overload the tires by exceeding the
specified load limit. The maximum permissible
load can be found on the vehicle's Tire and
Loading Information placard on the B-pillar on
the driver's side (Y page 271).
i The actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration.
DOT, Tire Identification Number (TIN) US tire regulations stipulate that every tire man-
ufacturer or retreader must imprint a TIN in or on the sidewall of each tire produced. The TIN is a unique identification number. The
TIN enables the tire manufacturers or retreaders to inform purchasers of recalls and other safety-
relevant matters. It makes it possible for the
purchaser to easily identify the affected tires.
The TIN is made up of manufacturer identifica-
tion code 0044, tire size 0087, tire type code 0085and
manufacturing date 0083.
DOT (Department of Transportation): tire
symbol 0043marks that the tire complies with the 278
All about wheels and tiresWheels and tires

Speed rating
The speed rating is part of the tire identification. It specifies the speed range for which the tire is
approved.
GVW (Gross Vehicle Weight)
The gross vehicle weight includes the weight of the vehicle with fuel, tools, the spare wheel,
accessories installed, vehicle occupants, lug-
gage and the drawbar noseweight if applicable.
The gross vehicle weight must not exceed the
gross vehicle weight rating GVWR as specified
on the vehicle identification plate on the B-pillar
on the driver's side.
GVWR (Gross Vehicle Weight Rating)
The GVWR is the maximum permitted gross
weight of the fully laden vehicle (weight of the
vehicle including all accessories, vehicle occu-
pants, fuel, luggage and the drawbar nose-
weight if applicable). The gross vehicle weight
rating is specified on the vehicle identification
plate on the B-pillar on the driver's side.
Maximum loaded vehicle weight
The maximum weight is the sum of:
R the curb weight of the vehicle
R the weight of the accessories
R the load limit
R the weight of the factory installed optional
equipment
Kilopascal (kPa) Metric unit for tire pressure. 6.9 kPa corre-
sponds to 1 psi. Another unit for tire pressure is
bar. 100 kilopascals (kPa) are the equivalent of
1 bar.
Load index
In addition to the load-bearing index, the load
index may also be imprinted on the sidewall of
the tire. This specifies the load-bearing capacityof the tire more precisely.
Curb weight The weight of a vehicle with standard equipment
including the maximum capacity of fuel, oil and
coolant. It also includes the air-conditioning sys- tem and optional equipment if these are instal-
led in the vehicle, but does not include passen-
gers or luggage. Maximum load rating
The maximum tire load is the maximum permis- sible weight in kilograms or lbs for which a tire is
approved.
Maximum permissible tire pressure Maximum permissible tire pressure for one tire.
Maximum load on one tire Maximum load on one tire. This is calculated by
dividing the maximum axle load of one axle by
two.
PSI (pounds per square inch)
A standard unit of measure for tire pressure.
Aspect ratioRelationship between tire height and tire width
in 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 per
square inch (psi), in kilopascal (kPa) or in bar.
The tire pressure should only be corrected when
the tires are cold.
Cold tire pressure
The tires are cold:
R if the vehicle has been parked with the tires
out of direct sunlight for at least three hours
and
R if the vehicle has not been driven further than
1 mile (1.6 km)
Tread The part of the tire that comes into contact with
the road.
Bead
The tire bead ensures that the tire sits securely
on the wheel. There are several steel wires in the bead to prevent the tire from coming loose from
the wheel rim.
Sidewall
The part of the tire between the tread and the
bead. 280
All about wheels and tiresWheels and tires