ECU MERCEDES-BENZ AMG GT ROADSTER 2019 Repair Manual

X
Pull out cover 0043.
X Screw in the towing eye clockwise to the stop.
Removing the towing eye X
Loosen the towing eye and unscrew it.
X Fully reinsert cover 0043.
X Put the towing eye back into the vehicle tool
kit. Towing a vehicle with both axles on
the ground
It is important that you observe the safety
instructions when towing away your vehicle
(Y page 258).
The automatic transmission automatically shifts
to position 005Dwhen you open the driver's or
front-passenger door or when you remove the
SmartKey from the ignition lock. In order to
ensure that the automatic transmission stays in position 005Cwhen towing away the vehicle, you
must observe the following points:
X Insert the SmartKey into the ignition lock. You
must use the SmartKey instead of the Start/
Stop button (Y page 111).
X Start the engine and leave it running during
the entire towing procedure.
X Depress and hold the brake pedal.
X Move the transmission to position 005Cwith the
E-SELECT lever.
X Check the transmission position using the
indicator in the multifunction display
(Y page 119).
X Release the brake pedal.
X Release the electric parking brake.
X Switch on the hazard warning lamps
(Y page 98). In order to signal a change of direction when
towing the vehicle with the hazard warning
lamps switched on, use the combination switch as usual. In this case, only the indicator lamps
for the direction of travel flash. After resetting
the combination switch, the hazard warning
lamp starts flashing again. Transporting the vehicle
!
When the vehicle is loaded for transport, the
front and rear axles must be stationary and on the same transportation vehicle. Positioning
over the connection point of the transport
vehicle is not permitted. The drive train may
otherwise be damaged.
! You may only secure the vehicle by the
wheels, not by parts of the vehicle such as
axle or steering components. Otherwise, the
vehicle could be damaged.
The towing eye can be used to pull the vehicle
onto a trailer or transporter for transporting pur- poses.
X Insert the SmartKey into the ignition lock. You
must use the SmartKey instead of the Start/
Stop button (Y page 111).
X Start the engine and leave it running during
the entire loading operation.
X Move the transmission to position 005Cwith the
E-SELECT lever.
X Check the transmission position using the
indicator in the multifunction display
(Y page 119).
As soon as the vehicle has been loaded:
X Prevent the vehicle from rolling away by
applying the electric parking brake.
X Shift the automatic transmission to position
005D. 260
Towing and tow-startingBreakdown assistance

X
Turn the SmartKey to key position 0092in the
ignition lock and remove it.
X Secure the vehicle. Tow-starting (emergency engine
starting)
! Vehicles with automatic transmission must
not be tow-started. You could otherwise dam- age the automatic transmission.
i You can find information on "Jump-starting"
under (Y page 256). Fuses
Important safety notes
G
WARNING
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.
Blown fuses must be replaced with fuses of the
same rating, which you can recognize by the
color and value. The fuse ratings are listed in the
fuse allocation chart.
The fuse allocation chart is on the fuse box in the trunk (Y page 262).
If a newly inserted fuse also blows, have the
cause traced and rectified at a qualified special-
ist workshop, e.g. an authorized Mercedes-Benz Center.
! Only use fuses that have been approved for
Mercedes-Benz vehicles and which have the
correct fuse rating for the system concerned.
Otherwise, components or systems could be
damaged.
! Make sure that no moisture can enter the
fuse box when the cover is open.
! When closing the cover, make sure that it is
lying 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 down
faulty circuits. If a fuse blows, all the compo-
nents on the circuit and their functions stop
operating. Before changing a fuse
X Switch off the engine.
X Switch off all electrical consumers.
X Open the driver's door.
The on-board electronics are now in key posi-
tion 0092. This is the same as the key having
been removed.
or, if the SmartKey is inserted in the ignition
lock: X Remove the SmartKey from the ignition lock.
X Secure the vehicle against rolling away
(Y page 127).
All indicator lamps in the instrument cluster
must be off. Fuse box in the front passenger foot-
well
! The floor panel must be installed properly,
otherwise moisture or dirt could impair the
function of the fuses. X
Open the front-passenger door.
X To open: remove the carpet over the footrest.
X Loosen screws 0043on the floor panel using a
suitable tool.
X Remove the floor panel.
X To close: install the floor panel again.
X Screw in and tighten screws 0043.
X Put in the carpet and press to secure. Fuses
261Breakdown assistance Z

Fuse box in the rear
X
To open: from the vehicle interior, lift up
cover 0043between the roll bars in the direction
of the arrow.
X To close: shut cover 0043in the opposite direc-
tion to the arrow and press to secure.
i The fuse allocation chart is located in the
trunk behind the service flap. You can find the
corresponding fuse rating and fuse type on
the fuse allocation chart. 262
FusesBreakdown assistance

Underinflated or overinflated tires
Underinflated tires G
WARNING
Tires with pressure that is too low can over-
heat and burst as a consequence. In addition, they also suffer from excessive and/or irreg-
ular wear, which can severely impair the brak- ing properties and the driving characteristics.There is a risk of an accident.
Avoid tire pressures that are too low in all the
tires, including the spare wheel.
Underinflated tires may:
R overheat, leading to tire defects
R adversely affect handling
R wear excessively and/or unevenly
R have an adverse effect on fuel consumption
Overinflated tires G
WARNING
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: R increase the braking distance
R adversely affect handling
R wear excessively and/or unevenly
R have an adverse effect on ride comfort
R be more susceptible to damage Maximum tire pressures 0043
Example: maximum permissible tire pres-
sure
Never exceed the maximum permissible tire
inflation pressure. Always observe the recom-
mended tire pressure for your vehicle when
adjusting the tire pressure (Y page 266).
i The actual values for tires are vehicle-spe-
cific and may deviate from the values in the
illustration. Checking the tire pressures
Important safety notes Observe the notes on tire pressure
(Y
page 266).
Information on air pressure for the tires on your
vehicle can be found:
R on the vehicle's Tire and Loading Information
placard on the B-pillar
R in the tire pressure table in the fuel filler flap
(Y page 126)
R in the "Tire pressure" section
Checking tire pressures manually To determine and set the correct tire pressure,
proceed as follows:
X Remove the valve cap of the tire that is to be
checked.
X Press the tire pressure gage securely onto the
valve.
X Read the tire pressure and compare it to the
recommended value on the Tire and Loading
Information placard or the tire pressure table
(Y page 266). 268
Tire pressureWheels 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

An arrow on the sidewall of the tire indicates its
correct direction of rotation. Storing wheels
Store wheels that are not being used in a cool,
dry and preferably dark place. Protect the tires
from oil, grease, gasoline and diesel. Mounting a wheel
Preparing the vehicle X
Stop the vehicle on solid, non-slippery and
level ground.
X Apply the electric parking brake manually.
X Bring the front wheels into the straight-ahead
position.
X Shift the transmission to position 005D.
X Switch off the engine.
X With KEYLESS-GO start function or vehi-
cles with KEYLESS-GO:
open the driver's
door.
The vehicle electronics are now in key posi-
tion 0092. This is the same as the SmartKey
having been removed.
or X Remove the SmartKey from the ignition lock.
X If included in the vehicle equipment, remove
the tire-change tool kit from the vehicle.
X Safeguard the vehicle against rolling away.
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
(Y page 249). The folding wheel chock is an additional safety
measure to prevent the vehicle from rolling
away, for example when changing a wheel.
X Fold both plates up 0043.
X Fold out lower plate 0044.
X Guide the lugs on the lower plate fully into the
openings in base plate 0087. X
Place chocks or other suitable items under
the front and rear of the wheel that is diago-
nally opposite the wheel you wish to change.
Raising the vehicle G
WARNING
If you do not position the jack correctly at the appropriate jacking point of the vehicle, the
jack could tip over with the vehicle raised.
There is a risk of injury.
Only position the jack at the appropriate jack-
ing point of the vehicle. The base of the jack
must be positioned vertically, directly under
the jacking point of the vehicle.
! Only position the jack at the appropriate
jacking point of the vehicle. Otherwise, you
could damage the vehicle.
Observe the following when raising the vehi- cle:
R To raise the vehicle, only use the vehicle-spe-
cific jack that has been tested and approved
by Mercedes-Benz. If used incorrectly, the
jack could tip over with the vehicle raised.
R The jack is designed only to raise and hold the
vehicle for a short time while a wheel is being
changed. It must not be used for performing
maintenance work under the vehicle.
R Avoid changing the wheel on uphill and down-
hill slopes. 282
Changing a wheelWheels and tires

R
Before raising the vehicle, secure it from roll-
ing away by applying the parking brake and
inserting wheel chocks. Do not disengage the parking brake while the vehicle is raised.
R The jack must be placed on a firm, flat and
non-slip surface. On a loose surface, a large,
flat, load-bearing underlay must be used. On a slippery surface, a non-slip underlay must be
used, e.g. rubber mats.
R Do not use wooden blocks or similar objects
as a jack underlay. Otherwise, the jack will not
be able to achieve its load-bearing capacity
due to the restricted height.
R Make sure that the distance between the
underside of the tires and the ground does not
exceed 1.2 in (3 cm).
R Do not place your hands or feet under the
raised vehicle.
R Do not lie under the vehicle.
R Do not start the engine when the vehicle is
raised.
R Do not open or close a door or the trunk lid
when the vehicle is raised.
R Make sure that no persons are present in the
vehicle when the vehicle is raised.
Vehicles with hub caps: the hub cap covers
the wheel bolts. Before you can unscrew the
wheel bolts, you must remove the hub cap. X
To remove: take socket0044and lug wrench
0087 from the vehicle tool kit (Y page 249).
X Position socket 0044on hub cap 0043.
X Position lug wrench 0087on socket 0044.
X Using lug wrench 0087, turn hub cap0043coun-
ter-clockwise and remove it.
X To install: before installing, check hub cap 0043
and the wheel area for soiling and clean if
necessary.
X Put hub cap 0043in position and turn until it is in
the right position. X
Position socket 0044on hub cap 0043.
X Attach lug wrench 0087to socket 0044and
tighten hub cap 0043.
The tightening torque must be
18 lb-ft (25 Nm).
i Note
that the hub cap should be tightened
to the specified torque of 18 lb-ft (25 Nm).
Mercedes-Benz recommends that you have
the hub cap installed at a qualified specialist
workshop. X
Using lug wrench 0087, loosen the bolts on the
wheel you wish to change by about one full
turn. Do not unscrew the bolts completely. The jacking point is centered between the front
and rear wheel arches (arrow). Changing a wheel
283Wheels and tires Z

X
Position jack 0083at jacking point 0085. X
Make sure that the base of the jack is posi-
tioned directly under jacking point 0085.
X Turn crank 0084clockwise until jack 0083sits
completely on jacking point 0085and the base
of the jack lies evenly on the ground.
X Turn crank 0084until the tire is raised a maxi-
mum of 1.2 in (3 cm) off the ground.
Removing a wheel !
AMG ceramic high performance composite
brake system:
When detaching or attaching the wheel, the
wheel rim may hit against the ceramic brake
disc and damage it.
Proceed with caution and seek the assistance of a second person.
! 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.
When mounting/removing wheels, and for as
long as the wheels are removed, avoid applying any external force on the brake disks. This could
impair the level of comfort when braking. X
Unscrew the uppermost wheel bolt com-
pletely.
X Screw alignment bolt 0043into the thread
instead of the wheel bolt.
X Unscrew the remaining wheel bolts fully.
X Remove the wheel.
Mounting a new wheel G
WARNING
Oiled or greased wheel bolts or damaged
wheel bolts/hub threads can cause the wheel 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 ofdamage to the threads, contact a qualified
specialist workshop immediately. Have the
damaged wheel bolts or hub threads
replaced/renewed. Do not continue driving. G
WARNING
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 and
safety notes in the "Changing a wheel" section
(Y page 281).
Only use wheel bolts that have been designed
for the wheel and the vehicle. For safety rea-
sons, Mercedes-Benz recommends that you
only use wheel bolts which have been approved for Mercedes-Benz vehicles and the respective
wheel.
! AMG ceramic high performance composite
brake system:
When detaching or attaching the wheel, the
wheel rim may hit against the ceramic brake
disc and damage it.
Proceed with caution and seek the assistance
of a second person.
! To prevent damage to the paintwork, hold
the wheel securely against the wheel hub
while screwing in the first wheel bolt. 284
Changing a wheelWheels and tires