MERCEDES-BENZ AMG GT ROADSTER 2018 Repair Manual

play messages which may be shown in the
instrument cluster (Ypage 175).
Brakes
XIf ABS intervenes:continue to depress the
brake pedal vigorously until the braking sit-
uation is over.
XTo make a full brake application: depress
the brake pedal with full force.
If ABS intervenes when braking, you will feel a
pulsing in the brake pedal.
The pulsating brake pedal can be an indication
of hazardous road conditions, and functions as a reminder to take extra care while driving.
BAS (Brake Assist System)
General information
BAS operates in emergency braking situations.
If you depress the brake pedal quickly, BAS
automatically boosts the braking force, thus
shortening the stopping distance.
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 58).
GWARNING
If BAS is malfunctioning, the braking distance
in an emergency braking situation is
increased. There is a risk of an accident.
In an emergency braking situation, depress
the brake pedal with full force. ABS prevents
the wheels from locking.
Braking
XKeep the brake pedal firmly depressed until
the emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will function as usual once you
release the brake pedal. BAS is deactivated.
Active Brake Assist
General information
iObserve the "Important safety notes" sec-
tion (Ypage 58).
Active Brake Assist consists of a distance warn-
ing function with an autonomous braking func-
tion and situation-dependent braking assis-
tance.
Active Brake Assist can help you to minimize the
risk of a collision with the vehicle traveling in
front or reduce the effects of such a collision.
If Active Brake Assist detects that there is a risk
of collision, you will be warned visually and
acoustically. If you do not react to the visual and audible collision warning, autonomous braking
can be initiated in critical situations. If you apply
the brake yourself in a critical situation, Active
Brake Assist supports you with situation-
dependent braking assistance.
Important safety notes
In particular, the detection of obstacles can be
impaired if:
Rthere is dirt on the sensors or anything else
covering the sensors
Rthere is snow or heavy rain
Rthere is interference by other radar sources
Rthere are strong radar reflections, for exam-
ple in parking garages
Ra narrow vehicle is traveling in front, e.g. a
motorbike
Ra vehicle is traveling in front on a different line
Ryou are driving a new vehicle or servicing on
the Active Brake Assist system has just been
carried out
Observe the important safety notes in the
"Breaking-in notes" section (
Ypage 109).
Following damage to the front end of the vehicle,
have the configuration and operation of the
radar sensor checked at a qualified specialist
workshop. This also applies to collisions at slow
speeds where there is no visible damage to the
front of the vehicle.
Activating/deactivating
Active Brake Assist is automatically active after
switching on the ignition.
Driving safety systems59
Safety
Z

You can activate or deactivate Active Brake
Assist (Ypage 168) in the on-board computer.
When deactivated, the distance warning func-
tion and the autonomous braking function are
also deactivated.
If Active Brake Assist is deactivated, the æ
symbol appears in the assistance graphic dis-
play.
Distance warning function
General information
The distance warning function can help you to
minimize the risk of a front-end collision with a
vehicle ahead or reduce the effects of such a
collision. If the distance warning function
detects that there is a risk of a collision, you will
be warned visually and acoustically.
Important safety notes
iObserve the "Important safety notes" sec-
tion for driving safety systems (Ypage 58).
GWARNING
The distance warning function does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen cornering
The distance warning function may not give
warnings in all critical situations. There is a
risk of an accident.
Always pay careful attention to the traffic sit-
uation and be ready to brake.
Always adapt your speed to suit the prevailing
road and traffic conditions.
GWARNING
The distance warning function cannot always
clearly identify objects and complex traffic
situations.
In such cases, the distance warning function
may:
Rgive an unnecessary warning
Rnot give a warning
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and do not rely solely on the distance
warning function.
Function
Starting at a speed of approximately 4 mph
(7 km/h), the distance warning function warns
you if you rapidly approach a vehicle in front. Anintermittent warning tone will then sound, and
the · distance warning lamp will light up in
the instrument cluster.
XBrake immediately in order to increase the
distance from the vehicle in front.
or
XTake evasive action provided it is safe to do
so.
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause the system to display a warning.
With the help of the radar sensor system, the
distance warning function can detect obstacles
that are in the path of your vehicle for an exten-
ded period of time.
Up to a speed of approximately 44 mph
(70 km/h), the distance warning function can
also react to stationary obstacles, such as stop-
ped or parked vehicles.
Autonomous braking function
If the driver does not react to the distance warn-
ing signal in a critical situation, Active Brake
Assist can assist the driver with the autonomous
braking function.
The autonomous braking function:
Rgives the driver more time to react to critical
driving situations
Rcan help the driver to avoid an accident or
Rreduces the effects of an accident
Vehicles without Distance Pilot DISTRONIC: the autonomous braking function is available in
the following speed ranges:
R4 - 65 mph (7 - 105 km/h) for moving objects
R4 - 31 mph (7 - 50 km/h) for stationary
objects
60Driving safety systems
Safety

Vehicles with Distance Pilot DISTRONIC:the
autonomous braking function is available in the
following speed ranges:
R4 - 124 mph (7 - 200 km/h) for moving
objects
R4 - 31 mph (7 - 50 km/h) for stationary
objects
Due to the nature of the system, particularly
complicated but non-critical driving conditions
may also cause the Autonomous Braking Func-
tion to intervene.
If the autonomous braking function requires a
particularly high braking force, preventative
passenger protection measures (PRE-SAFE
®)
are activated simultaneously (Ypage 54).
Situation-dependent braking assis-
tance
General information
iObserve the "Important safety notes" sec-
tion (Ypage 58).
With the help of the radar sensor system, Active Brake Assist can detect obstacles that are in the
path of your vehicle for an extended period of
time.
If Active Brake Assist detects a risk of collision
with the vehicle in front, it calculates the brake
pressure necessary to avoid a collision. If you
apply the brakes forcefully, situation-dependent
braking assistance adapts to the situation and
automatically increases the brake pressure to a
degree appropriate to the traffic situation.
Situation-dependent braking assistance pro-
vides braking assistance in hazardous situations
at speeds above 4 mph (7 km/h). It uses radar
sensor technology to assess the traffic situa-
tion.
Situation-dependent braking assistance is capa-
ble of reacting to moving objects that have
already been detected as such at least once
over the period of observation, up to vehicle
speeds of around 155 mph (250 km/h).
Situation-dependent braking assistance reacts
to stationary obstacles up to a speed of approx-
imately 44 mph (70 km/h).
If situation-dependent braking assistance
demands particularly high brake pressure, pre-
ventative passenger protection measures (PRE-
SAFE
®) are triggered simultaneously
(Ypage 54).
XKeep the brake pedal depressed until the
emergency braking situation is over.
ABS prevents the wheels from locking.
The brakes will work normally again if:
Ryou release the brake pedal
Rthere is no longer any danger of a collision
Rno obstacle is detected in front of your vehicle
Situation-dependent braking assistance is then
deactivated.
Important safety notes
iObserve the "Important safety notes" sec-
tion for driving safety systems (Ypage 58).
GWARNING
Adaptive Brake Assist does not react:
Rto people or animals
Rto oncoming vehicles
Rto crossing traffic
Rwhen cornering
As a result, Adaptive Brake Assist may not
intervene in all critical conditions. There is a
risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake.
GWARNING
Adaptive Brake Assist cannot always clearly
identify objects and complex traffic situa-
tions.
In such cases, Adaptive Brake Assist might:
Rintervene unnecessarily
Rnot intervene
There is a risk of an accident.
Always pay careful attention to the traffic sit- uation and be ready to brake. Terminate the
intervention in a non-critical driving situation.
Due to the nature of the system, complex but
non-critical driving conditions may also cause
Active Brake Assist to intervene.
Even if Active Brake Assist is not available due to
a malfunction in the radar sensor system, the
brake system is still available with full brake
boosting effect and BAS.
Driving safety systems61
Safety
Z

ESP®(Electronic Stability Program)
General notes
iObserve the "Important safety notes" sec-
tion (Ypage 58).
ESP
®monitors driving stability and traction, i.e.
power transmission between the tires and the
road surface.
If ESP
®detects that the vehicle is deviating from
the direction desired by the driver, one or more
wheels are braked to stabilize the vehicle. The
engine output is also modified to keep the vehi-
cle on the desired course within physical limits.
ESP
®assists the driver when pulling away on
wet or slippery roads. ESP®can also stabilize
the vehicle during braking.
ETS (Electronic Traction System)
iObserve the "Important safety notes" sec-
tion (Ypage 58).
ETS traction control is part of ESP
®.
Traction control brakes the drive wheels indi-
vidually if they spin. This enables you to pull
away and accelerate on slippery surfaces, for
example if the road surface is slippery on one
side. In addition, more drive torque is transfer-
red to the wheel or wheels with traction.
Traction control remains active, even if you
deactivate ESP
®.
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 58).
GWARNING
If ESP
®is malfunctioning, ESP®is unable to
stabilize the vehicle. Additionally, further driv-
ing safety systems are deactivated. This
increases the risk of skidding and an accident.
Drive on carefully. Have ESP
®checked at a
qualified specialist workshop.
ESP
®is only deactivated if the åwarning
lamp is lit continuously.
When SPORT handling mode is activated, the
M warning lamp lights up in the instrument
panel. When the
åandh warning lamps light up
continuously, ESP
®is not available due to a mal-
function.
Observe the information on warning lamps
(
Ypage 200) and display messages which may
be shown in the instrument cluster
(
Ypage 175).
Only use wheels with the recommended tire
sizes. Only then will ESP
®function properly.
Characteristics of ESP®
General information
If the ÷ ESP®warning lamp goes out before
beginning the journey, ESP®is automatically
active.
If ESP
®intervenes, the ÷ESP®warning lamp
flashes in the instrument cluster.
If ESP
®intervenes:
XDo not deactivate ESP®under any circum-
stances.
XOnly depress the accelerator pedal as far as
necessary when pulling away.
XAdapt your driving style to suit the prevailing
road and weather conditions.
ECO start/stop function
The ECO start/stop function switches the
engine off automatically when the vehicle stops
moving. The engine starts automatically when
the driver wants to pull away again. ESP
®
remains in its previously selected status. Exam-
ple: if ESP®was deactivated before the engine
was switched off, ESP®remains deactivated
when the engine is switched on again.
Deactivating/activating ESP®
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 58).
You can select between the following states of
ESP
®:
RESP®is activated
RSPORT handling mode is activated
RESP®is deactivated
62Driving safety systems
Safety

GWARNING
If you deactivate ESP
®, ESP®no longer sta-
bilizes the vehicle. There is an increased risk
of skidding and an accident.
Only deactivate ESP
®in the situations descri-
bed in the following.
GWARNING
When SPORT handling mode is activated,
there is a greater risk of skidding and acci-
dents.
Only activate SPORT handling mode in the sit-
uations described in the following.
In the following situations, it may be better to
activate SPORT handling mode or deactivate
ESP
®:
Rwhen using snow chains
Rin deep snow
Ron sand or gravel
Ron specially designated roads when the vehi-
cle's own oversteering and understeering
characteristics are desired
Driving in SPORT handling mode or without
ESP
®requires an extremely qualified and expe-
rienced driver.
Activate ESP
®as soon as the situations descri-
bed above no longer apply. ESP®will otherwise
not be able to stabilize the vehicle if the vehicle
starts to skid or a wheel starts to spin.
!Avoid spinning the driven wheels for an
extended period with ESP®deactivated. You
could otherwise damage the drivetrain.
Deactivating/activating ESP®
XTo activate SPORT handling mode: briefly
press button :.
The M handling mode warning lamp in the
instrument cluster lights up. The SPORT
han‐dling modemessage appears on the multi-
function display.
XTo deactivate SPORT handling mode:
briefly press button :.
The M handling mode warning lamp in the
instrument cluster goes out. ESP
®is activa-
ted
XTo deactivate ESP®: press button :.
The å ESP®OFF warning lamp in the
instrument cluster lights up. The ÷OFF
message appears on the multifunction dis-
play.
XTo activate ESP®:when SPORT handling
mode is activated or ESP®is deactivated,
press button :.
The å ESP
®OFF warning lamp in the
instrument cluster goes out. The ÷ON
message appears on the multifunction dis-
play.
Characteristics of activated SPORT han-
dling mode
If SPORT handling mode is activated and one or
more wheels start to spin, the ÷ESP®warn-
ing lamp in the instrument cluster flashes. ESP®
only stabilizes the vehicle to a limited degree.
When SPORT handling mode is activated:
RESP®only improves driving stability to a limi-
ted degree
Rtraction control is still activated
Rengine torque is no longer limited and the
drive wheels are able to spin
The spinning of the wheels results in a cut for
better traction on loose surfaces.
RESP®still provides support when you brake
firmly
Characteristics when ESP®is deactivated
If ESP®is deactivated and one or more wheels
start to spin, the ÷ESP®warning lamp in the
instrument cluster flashes. In such situations,
ESP
®will not stabilize the vehicle.
If you deactivate ESP®:
RESP®no longer improves driving stability
Rengine torque is no longer limited and the
drive wheels are able to spin
Driving safety systems63
Safety
Z

The spinning of the wheels results in a cut for
better traction on loose surfaces.
Rtraction control is still activated
RAdaptive Brake Assist is unavailable
Active Brake Assist is also not activated if you
brake firmly with assistance from ESP
®.
RPRE-SAFE®is unavailable
PRE-SAFE®is also not activated if you brake
firmly with assistance from ESP®.
RESP®still provides support when you brake
firmly
EBD (electronic brake force distribu-
tion)
General information
EBD monitors and controls the brake pressure
on the rear wheels to improve driving stability
while braking.
Important safety notes
iObserve the "Important safety notes" sec-
tion (Ypage 58).
GWARNING
If EBD is malfunctioning, the rear wheels can
lock, e.g. under full braking. This increases the
risk of skidding and an accident.
You should therefore adapt your driving style
to the different handling characteristics. Have
the brake system checked at a qualified spe-
cialist workshop.
Observe information regarding indicator and
warning lamps (
Ypage 200) as well as display
messages (Ypage 177).
ADAPTIVE BRAKE
ADAPTIVE BRAKE enhances braking safety and
offers increased braking comfort. In addition to
the braking function, ADAPTIVE BRAKE also fea-
tures the hill start assist function (
Ypage 112).
Protection against theft
Immobilizer
The immobilizer prevents your vehicle from
being started without the correct SmartKey.
XTo activate with KEYLESS-GO start-func-
tion or KEYLESS-GO: switch the ignition off
and open the driver's door.
XTo activate with the SmartKey: remove the
SmartKey from the ignition lock.
XTo deactivate: switch on the ignition.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Anyone
can start the engine if a valid SmartKey has been
left inside the vehicle.
iThe immobilizer is always deactivated when
you start the engine.
In the event that the engine cannot be started
(yet the vehicle's battery is charged), the sys-
tem is not operational. Contact an authorized
Mercedes-Benz Center or call
1-800-FOR-MERCedes (in the USA) or
1-800-387-0100 (in Canada).
ATA (anti-theft alarm system)
XTo arm: lock the vehicle with the SmartKey or
KEYLESS-GO.
Indicator lamp :flashes. The alarm system
is armed after approximately 15 seconds.
XTo disarm: unlock the vehicle with the Smart-
Key or KEYLESS-GO.
or
XWith KEYLESS-GO start function or vehi-
cles with KEYLESS-GO: press the Start/
Stop button.
The SmartKey must be in the vehicle.
64Protection against theft
Safety

or
XInsert the SmartKey into the ignition lock.
A visual and audible alarm is triggered if the
alarm system is armed and you open:
Ra door
Rthe vehicle with the mechanical key
Rthe trunk lid
Rthe hood
Rthe glove box
XTo turn the alarm off with the SmartKey:
press the %or& button on the Smart-
Key.
The alarm is stopped.
or
XInsert the SmartKey into the ignition lock.
The alarm is stopped.
XTo stop the alarm using KEYLESS-GO:
grasp the outside door handle. The SmartKey
must be outside the vehicle.
The alarm is stopped.
or
XPress the Start/Stop button. The SmartKey
must be inside the vehicle.
The alarm is stopped.
The alarm is not switched off, even if you close
the open door that triggered it, for example.
iIf the alarm continues for more than
30 seconds, the mbrace emergency call sys-
tem automatically notifies the Customer
Assistance Center. This is done either by text
message or data connection.
The emergency call system sends a message
or establishes a data connection provided
that:
Ryou have subscribed to the mbrace service.
Rthe mbrace service has been activated
properly.
Rthe necessary mobile phone network is
available.
Protection against theft65
Safety
Z

SmartKey
Important safety notes
GWARNING
If children are left unsupervised in the vehicle,
they could:
Ropen the doors, thus endangering other
people or road users.
Rget out and disrupt traffic.
Roperate the vehicle's equipment.
Additionally, children could set the vehicle in
motion if, for example, they:
Rrelease the parking brake.
Rshifting the automatic transmission out of
park position P
RStart the engine.
There is a risk of an accident and injury.
When leaving the vehicle, always take the
SmartKey with you and lock the vehicle. Never
leave children or animals unattended in the
vehicle. Always keep the SmartKey out of
reach of children.
GWARNING
If you attach heavy or large objects to the
SmartKey, the SmartKey could be uninten-
tionally turned in the ignition lock. This could
cause the engine to be switched off. There is a risk of an accident.
Do not attach any heavy or large objects to the
SmartKey. Remove any bulky key rings before
inserting the SmartKey into the ignition lock.
!Keep the SmartKey away from strong mag-
netic fields. Otherwise, the remote control
function could be affected.
Strong magnetic fields can occur in the vicin-
ity of powerful electrical installations.
Do not keep the SmartKey:
Rwith electronic devices, e.g. a mobile phone
or another SmartKey
Rwith metallic objects, e.g. coins or metal foil
Rinside metallic objects, e.g. a metal case
This can affect the functionality of the Smart-
Key. Vehicles with KEYLESS-GO start function:
do
not keep the SmartKey in the trunk. Otherwise,
the SmartKey may not be detected, e.g. when
starting the engine using the Start/Stop button.
A brief radio connection between the vehicle
and the SmartKey determines whether a valid
SmartKey is in, or in the direct vicinity of, the
vehicle. This occurs, for example:
Rwhen starting the engine
Rwhile driving
Rwhen using the trunk unlocking sensor
Rwhen the external door handles are touched
Rduring convenience closing
SmartKey functions
:& Locks the vehicle
;FOpens the trunk lid
=%Unlocks the vehicle
XTo unlock centrally: press the%button.
If you do not open the vehicle within approx-
imately 40 seconds of unlocking:
Rthe vehicle is locked again
Rthe anti-theft alarm system is armed again.
XTo lock centrally: press the&button.
The SmartKey centrally locks and unlocks the
doors, the glove box and the fuel filler flap.
The turn signals flash once when unlocking and
three times when locking.
You can also set an audible signal to confirm
that the vehicle has been locked. The audible
signal can be activated and deactivated via the
multimedia system; see the Digital Operator's
Manual.
When the locator lighting is activated via the
multimedia system, it lights up when it is dark
after the vehicle is unlocked with the SmartKey.
66SmartKey
Opening and closing

Information on activating and deactivating the
locator lighting can be found in the Digital Oper-
ator's Manual.
XTo open the trunk lid:press and hold the
F button until the trunk lid opens.
KEYLESS-GO
General notes
Bear in mind that the engine can be started by
any of the vehicle occupants if there is a Smart-
Key in the vehicle (
Ypage 112).
Locking/unlocking centrally
You can start, lock or unlock the vehicle using
KEYLESS-GO. To do this, you only need carry the
SmartKey with you. You can combine the func-
tions of KEYLESS-GO with those of a conven-
tional SmartKey. Unlock the vehicle by using
KEYLESS-GO, for instance, and lock it using the
& button on the SmartKey.
The driver's door and the door at which the han-
dle is used, must both be closed. The SmartKey
must be outside the vehicle. When locking or
unlocking with KEYLESS-GO, the distance
between the SmartKey and the corresponding
door handle must not be greater than 3 ft (1 m).
A check which periodically establishes a radio
connection between the vehicle and the Smart-
Key determines whether a valid SmartKey is in
the vehicle. This occurs, for example:
Rwhen starting the engine
Rwhile driving
Rwhen using the remote trunk lid opening sen- sor
Rwhen the external door handles are touched
Rduring convenience closing
XTo unlock the vehicle: touch the inner sur-
face of the door handle.
XTo lock the vehicle: touch sensor surface :
or ;.
Make sure that you do not touch the inner
surface of the door handle.
XConvenience closing feature: touch
recessed sensor surface ;for an extended
period.
Further information on the convenience clos-
ing feature (
Ypage 78).
Deactivating and activating
If you do not intend to use the vehicle for a lon-
ger period of time, you can deactivate KEYLESS-
GO. The SmartKey will then use very little power,
thereby conserving battery power. For the pur-
poses of activation/deactivation, the vehicle
must not be nearby.
XTo deactivate: press the&button on the
SmartKey twice in rapid succession.
The indicator light on the SmartKey flashes
twice briefly then one long flash, then KEY-
LESS-GO is deactivated (
Ypage 69).
XTo activate: press any button on the Smart-
Key.
or
XInsert the SmartKey into the ignition lock.
KEYLESS-GO and all of its associated features
are available again.
KEYLESS-GO start function
Bear in mind that the engine can be started by
any of the vehicle occupants if there is a Smart-
Key in the vehicle (
Ypage 112).
Changing the settings of the locking
system
You can change the settings of the locking sys-
tem. This means that only the driver's door, the
glove compartment and the fuel filler flap are
unlocked when the vehicle is unlocked. This is
useful if you frequently travel on your own.
XTo change the setting: press and hold down
the % and& buttons simultaneously
SmartKey67
Opening and closing
Z

for about six seconds until the battery indica-
tor lamp flashes twice (Ypage 69).
If the setting of the locking system is changed
within the signal range of the vehicle, pressing
the & or% button:
Rlocks or
Runlocks the vehicle
The SmartKey now functions as follows:
XTo unlock: press the%button once.
XTo unlock centrally: press the%button
twice.
XTo lock: press the &button.
The KEYLESS-GO functions can be changed as
follows:
XTo unlock the driver's door: touch the inner
surface of the door handle on the driver's
door.
XTo unlock centrally: touch the inner surface
of the front-passenger door handle.
XTo lock centrally: touch the outer sensor
surface on one of the door handles.
Restoring factory settings:
XPress the %and& buttons simultane-
ously for approximately six seconds until the
battery check lamp flashes twice
(
Ypage 69).
Mechanical key
General notes
If the vehicle can no longer be locked or
unlocked with the SmartKey or KEYLESS-GO,
use the mechanical key.
If you use the mechanical key to unlock and
open the driver's door, the anti-theft alarm sys-
tem will be triggered. Switch off the alarm
(
Ypage 64).
If you unlock the vehicle using the mechanical
key, the fuel filler flap will not be unlocked auto-
matically.
XTo unlock the fuel filler flap: insert the
SmartKey into the ignition lock.
Removing the mechanical key
XPush release catch :in the direction of the
arrow and at the same time remove mechan- ical key ;from the SmartKey.
For further information about:
Runlocking the driver's door (Ypage 73)
Rlocking the vehicle (Ypage 73)
Inserting the mechanical key
XPush mechanical key ;completely into the
SmartKey until it engages and release
catch :is back in its basic position.
SmartKey battery
Important safety notes
GWARNING
Batteries contain toxic and corrosive substan- ces. If batteries are swallowed, it can result in
severe health problems. There is a risk of fatalinjury.
Keep batteries out of the reach of children. If
a battery is swallowed, seek medical attention immediately.
HEnvironmental note
Batteries contain dangerous
substances. It is against the
law to dispose of them with
the household rubbish. They
must be collected separately
68SmartKey
Opening and closing