brakes JEEP WRANGLER UNLIMITED 2021 Owner handbook (in English)

78
(Continued)
SAFETY
SAFETY FEATURES
Anti-Lock Brake System (ABS)
The Anti-Lock Brake System (ABS) provides
increased vehicle stability and brake perfor-
mance under most braking conditions. The
system automatically prevents wheel lock,
and enhances vehicle control during braking.
The ABS performs a self-check cycle to
ensure that the ABS is working properly each
time the vehicle is started and driven. During
this self-check, you may hear a slight
clicking sound as well as some related motor
noises.
ABS is activated during braking when the
system detects one or more wheels begin to
lock. Road conditions such as ice, snow,
gravel, bumps, railroad tracks, loose debris,
or panic stops may increase the likelihood of
ABS activation(s). You also may experience the following when
ABS activates:
The ABS motor noise (it may continue to
run for a short time after the stop)
The clicking sound of solenoid valves
Brake pedal pulsations
A slight drop of the brake pedal at the end
of the stop
These are all normal characteristics of ABS.
ABS is designed to function with the Original
Equipment Manufacturer (OEM) tires. Modi-
fication may result in degraded ABS perfor -
mance.
Anti-Lock Brake Warning Light
The yellow “Anti-Lock Brake Warning Light”
will turn on when the ignition is placed in the
ON/RUN mode and may stay on for as long
as four seconds.
WARNING!

The ABS contains sophisticated electronic
equipment that may be susceptible to inter -
ference caused by improperly installed or
high output radio transmitting equipment.
This interference can cause possible loss of
anti-lock braking capability. Installation of
such equipment should be performed by
qualified professionals.

Pumping of the Anti-Lock Brakes will
diminish their effectiveness and may
lead to a collision. Pumping makes the
stopping distance longer. Just press
firmly on your brake pedal when you
need to slow down or stop.
The ABS cannot prevent the natural laws
of physics from acting on the vehicle, nor
can it increase braking or steering effi -
ciency beyond that afforded by the
condition of the vehicle brakes and tires
or the traction afforded.
The ABS cannot prevent collisions,
including those resulting from excessive
speed in turns, following another vehicle
too closely, or hydroplaning.
The capabilities of an ABS equipped
vehicle must never be exploited in a
reckless or dangerous manner that could
jeopardize the user’s safety or the safety
of others.
WARNING! (Continued)
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79
If the “Anti-Lock Brake Warning Light”
remains on or comes on while driving, it indi-
cates that the anti-lock portion of the brake
system is not functioning and that service is
required. However, the conventional brake
system will continue to operate normally if
the “Anti-Lock Brake Warning Light” is on.
If the “Anti-Lock Brake Warning Light” is on,
the brake system should be serviced as soon
as possible to restore the benefits of
anti-lock brakes. If the “Anti-Lock Brake
Warning Light” does not come on when the
ignition is placed in the ON/RUN mode, have
the light repaired as soon as possible.
Electronic Brake Control (EBC) System

Your vehicle is equipped with an advanced
Electronic Brake Control (EBC) system. This
system includes Electronic Brake Force Distri -
bution (EBD), Anti-Lock Brake System (ABS),
Brake Assist System (BAS), Hill Start Assist
(HSA), Traction Control System (TCS), Elec-
tronic Stability Control (ESC), and Electronic
Roll Mitigation (ERM). These systems work
together to enhance both vehicle stability and
control in various driving conditions.
Your vehicle may also be equipped with
Trailer Sway Control (TSC), Ready Alert
Braking (RAB), Rain Brake Support (RBS),
and Hill Descent Control (HDC).
Brake System Warning Light
The red “Brake System Warning Light” will
turn on when the ignition is placed in the
ON/RUN mode and may stay on for as long
as four seconds.
If the “Brake System Warning Light”
remains on or comes on while driving, it indi
-
cates that the brake system is not func -
tioning properly and that immediate service
is required. If the “Brake System Warning
Light” does not come on when the ignition is
placed in the ON/RUN mode, have the light
repaired as soon as possible.
Brake Assist System (BAS)
The Brake Assist System (BAS) is designed
to optimize the vehicle’s braking capability
during emergency braking maneuvers. The
system detects an emergency braking situa -
tion by sensing the rate and amount of brake
application and then applies optimum pres -
sure to the brakes. This can help reduce
braking distances. The BAS complements
the Anti-Lock Brake System (ABS). Applying the brakes very quickly results in the best
BAS assistance. To receive the benefit of the
system, you must apply continuous braking
pressure during the stopping sequence, (do
not “pump” the brakes). Do not reduce brake
pedal pressure unless braking is no longer
desired. Once the brake pedal is released,
the BAS is deactivated.
WARNING!
The Brake Assist System (BAS) cannot
prevent the natural laws of physics from
acting on the vehicle, nor can it increase
the traction afforded by prevailing road
conditions. BAS cannot prevent collisions,
including those resulting from excessive
speed in turns, driving on very slippery
surfaces, or hydroplaning. The capabilities
of a BAS-equipped vehicle must never be
exploited in a reckless or dangerous
manner, which could jeopardize the user's
safety or the safety of others.
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83
The “ESC Activation/Malfunction Indicator
Light” (located in the instrument cluster)
starts to flash as soon as the tires lose trac-
tion and the ESC system becomes active.
The “ESC Activation/Malfunction Indicator
Light” also flashes when TCS is active. If the
“ESC Activation/Malfunction Indicator
Light” begins to flash during acceleration,
ease up on the accelerator and apply as little
throttle as possible. Be sure to adapt your
speed and driving to the prevailing road
conditions.
NOTE:
The “ESC Activation/Malfunction Indi -
cator Light” and the “ESC OFF Indicator
Light” come on momentarily each time
the ignition is turned ON.
Each time the ignition is turned ON, the
ESC system will be on even if it was turned
off previously.
The ESC system will make buzzing or
clicking sounds when it is active. This is
normal; the sounds will stop when ESC
becomes inactive following the maneuver
that caused the ESC activation. The “ESC OFF Indicator Light”
indicates the customer has elected
to have the Electronic Stability
Control (ESC) in a reduced mode.
Hill Descent Control (HDC) — If Equipped
Hill Descent Control (HDC) is intended for
low speed off road driving while in 4L Range.
HDC maintains vehicle speed while
descending hills during various driving situa
-
tions. HDC controls vehicle speed by actively
controlling the brakes.
HDC has three states:
1. Off (feature is not enabled and will not activate)
2. Enabled (feature is enabled and ready but activation conditions are not met, or
driver is actively overriding with brake or
throttle application)
3. Active (feature is enabled and actively controlling vehicle speed) Enabling HDC
HDC is enabled by pushing the HDC switch,
but the following conditions must also be
met to enable HDC:
Driveline is in 4L Range
Vehicle speed is below 5 mph (8 km/h)
Park brake is released
Driver door is closed (If doors are
attached, then door must be closed. If
doors are detached, then driver seatbelt
must be buckled)
Activating HDC
Once HDC is enabled it will activate auto -
matically if driven down a grade of sufficient
magnitude. The set speed for HDC is select -
able by the driver, and can be adjusted by
using the gear shift +/-. The following
summarizes the HDC set speeds:
HDC Target Set Speeds
P = No set speed. HDC may be enabled
but will not activate
R = 0.6 mph (1 km/h)
N = 1.2 mph (2 km/h)
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85
The cluster icon and switch indicator light
will flash when HDC deactivates due to
overheated brakes. The flashing will stop
and HDC will activate again once the
brakes have cooled sufficiently.
Hill Start Assist (HSA)

The Hill Start Assist (HSA) system is designed to
mitigate roll back from a complete stop while on
an incline. If the driver releases the brake while
stopped on an incline, HSA will continue to hold
the brake pressure for a short period. If the driver
does not apply the throttle before this time
expires, the system will release brake pressure
and the vehicle will roll down the hill as normal.
The following conditions must be met in
order for HSA to activate:
The feature must be enabled
The vehicle must be stopped
Park brake must be off
Driver door must be closed. (If the doors
are attached, then the door must be
closed. If the doors are detached then the
driver's seatbelt must be buckled)
The vehicle must be on a sufficient grade
The gear selection must match vehicle
uphill direction (i.e., vehicle facing uphill
is in forward gear; vehicle backing uphill is
in REVERSE (R) gear)
HSA will work in REVERSE gear and all
forward gears. The system will not activate
if the transmission is in PARK (P) or
NEUTRAL (N). For vehicles equipped with
a manual transmission, if the clutch is
pressed, HSA will remain active.
Disabling And Enabling HSA
This feature can be turned on or turned off.
To change the current setting, refer to
“Instrument Cluster Display” in “Getting To
Know Your Instrument Panel” for further
information.
WARNING!
HDC is only intended to assist the driver in
controlling vehicle speed when descending
hills. The driver must remain attentive to
the driving conditions and is responsible
for maintaining a safe vehicle speed.
WARNING!
There may be situations where the Hill
Start Assist (HSA) will not activate and
slight rolling may occur, such as on minor
hills or with a loaded vehicle, or while
pulling a trailer. HSA is not a substitute for
active driving involvement. It is always the
driver’s responsibility to be attentive to
distance to other vehicles, people, and
objects, and most importantly brake
operation to ensure safe operation of the
vehicle under all road conditions. Your
complete attention is always required
while driving to maintain safe control of
your vehicle. Failure to follow these
warnings can result in a collision or serious
personal injury.
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SAFETY
86
Towing With HSA
HSA will also provide assistance to mitigate
roll back while towing a trailer.
Ready Alert Braking (RAB)
Ready Alert Braking (RAB) may reduce the
time required to reach full braking during
emergency braking situations. It anticipates
when an emergency braking situation may
occur by monitoring how fast the throttle is
released by the driver. The Electronic Brake
Control (EBC) system will prepare the brake
system for a panic stop.
Rain Brake Support (RBS)
Rain Brake Support (RBS) may improve
braking performance in wet conditions. It
will periodically apply a small amount of
brake pressure to remove any water buildup
on the front brake rotors. It functions when
the windshield wipers are in LO or HI speed.
When RBS is active, there is no notification
to the driver and no driver interaction is
required.
Trailer Sway Control (TSC)
Trailer Sway Control (TSC) uses sensors in
the vehicle to recognize an excessively
swaying trailer and will take the appropriate
actions to attempt to stop the sway. TSC will
become active automatically once an exces-
sively swaying trailer is recognized.

NOTE:
TSC cannot stop all trailers from swaying.
Always use caution when towing a trailer and
follow the trailer tongue weight recommenda-
tions. Refer to “Trailer Towing” in “Starting
And Operating” for further information.

When TSC is functioning, the “ESC Activa -
tion/Malfunction Indicator Light” will flash,
the engine power may be reduced and you
may feel the brakes being applied to indi -
vidual wheels to attempt to stop the trailer
from swaying. TSC is disabled when the ESC
system is in the “Partial Off” or “Full Off”
modes.
WARNING!
If you use a trailer brake controller with
your trailer, the trailer brakes may be
activated and deactivated with the brake
switch. If so, there may not be enough
brake pressure to hold both the vehicle
and the trailer on a hill when the brake
pedal is released. In order to avoid
rolling down an incline while resuming
acceleration, manually activate the
trailer brake or apply more vehicle brake
pressure prior to releasing the brake
pedal.
HSA is not a parking brake. Always apply
the parking brake fully when exiting your
vehicle. Also, be certain to place the
transmission in PARK (P).
Failure to follow these warnings can
result in a collision or serious personal
injury. WARNING!
If TSC activates while driving, slow the
vehicle down, stop at the nearest safe
location, and adjust the trailer load to
eliminate trailer sway.
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SAFETY
90
system determines that a forward collision is
probable, the driver will be provided with
audible and visual warnings as well as a
possible haptic warning in the form of a
brake jerk.
If the driver does not take action based upon
these progressive warnings, then the system
will provide a limited level of active braking
to help slow the vehicle and mitigate the
potential forward collision. If the driver
reacts to the warnings by braking and the
system determines that the driver intends to
avoid the collision by braking but has not
applied sufficient brake force, the system
will compensate and provide additional
brake force as required.
If a FCW with Mitigation event begins at a
speed below 32 mph (52 km/h), the system
may provide the maximum braking possible
to mitigate the potential forward collision. If
the Forward Collision Warning with Mitiga-
tion event stops the vehicle completely, the
system will hold the vehicle at standstill for
two seconds and then release the brakes. FCW Message

When the system determines a collision with
the vehicle in front of you is no longer probable,
the warning message will be deactivated.

NOTE:
The minimum speed for FCW activation is
3 mph (5 km/h).

The FCW alerts may be triggered on objects
other than vehicles such as guard rails or sign
posts based on the course prediction. This is
expected and is a part of normal FCW activa-
tion and functionality.

It is unsafe to test the FCW system. To prevent
such misuse of the system, after four Active
Braking events within a key cycle, the Active Braking portion of FCW will be deactivated
until the next Key Cycle.

The FCW system is intended for on-road
use only. If the vehicle is taken off-road,
the FCW system should be deactivated to
prevent unnecessary warnings to the
surroundings.
FCW may not react to irrelevant objects
such as overhead objects, ground reflec-
tions, objects not in the path of the
vehicle, stationary objects that are far
away, oncoming traffic, or leading vehicles
with the same or higher rate of speed.
FCW will be disabled like ACC, with the
unavailable screens.
WARNING!
Forward Collision Warning (FCW) is not
intended to avoid a collision on its own,
nor can FCW detect every type of potential
collision. The driver has the responsibility
to avoid a collision by controlling the
vehicle via braking and steering. Failure to
follow this warning could lead to serious
injury or death.
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STARTING AND OPERATING
144
(Continued)
Ignition Park Interlock
This vehicle is equipped with an Ignition
Park Interlock which requires the transmis-
sion to be in PARK before the ignition can be
turned to the OFF mode. This helps the
driver avoid inadvertently leaving the vehicle
without placing the transmission in PARK.
This system also locks the transmission in
PARK whenever the ignition is in the OFF
mode. NOTE:
The transmission is NOT locked in PARK
when the ignition is in the ACC mode (even
though the engine will be off). Ensure that
the transmission is in PARK, and the ignition
is
OFF (not in ACC mode) before exiting the
vehicle.
Brake/Transmission Shift Interlock
System
This vehicle is equipped with a Brake Trans -
mission Shift Interlock system (BTSI) that
holds the transmission gear selector in PARK
unless the brakes are applied. To shift the
transmission out of PARK, the engine must
be running and the brake pedal must be
pressed. The brake pedal must also be
pressed to shift from NEUTRAL into DRIVE
or REVERSE when the vehicle is stopped or
moving at low speeds.
It is dangerous to shift out of PARK or
NEUTRAL if the engine speed is higher
than idle speed. If your foot is not firmly
pressing the brake pedal, the vehicle
could accelerate quickly forward or in
reverse. You could lose control of the
vehicle and hit someone or something.
Only shift into gear when the engine is
idling normally and your foot is firmly
pressing the brake pedal.
Unintended movement of a vehicle could
injure those in or near the vehicle. As
with all vehicles, you should never exit a
vehicle while the engine is running.
Before exiting a vehicle, always come to
a complete stop, then apply the parking
brake, shift the transmission into PARK,
and turn the ignition OFF. When the igni -
tion is in the OFF mode, the transmis-
sion is locked in PARK, securing the
vehicle against unwanted movement.
When exiting the vehicle, always make
sure the ignition is in the OFF mode,
remove the key fob from the vehicle, and
lock the vehicle.
WARNING! (Continued)
Never leave children alone in a vehicle,
or with access to an unlocked vehicle.
Allowing children to be in a vehicle unat -
tended is dangerous for a number of
reasons. A child or others could be seri -
ously or fatally injured. Children should
be warned not to touch the parking
brake, brake pedal or the transmission
gear selector.
Do not leave the key fob in or near the
vehicle (or in a location accessible to
children), and do not leave the ignition
in the ACC or ON/RUN mode. A child
could operate power windows, other
controls, or move the vehicle.
WARNING! (Continued)
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159
To Set A Desired ACC Speed
When the vehicle reaches the speed desired,
push the SET (+) button or the SET (-) button
and release. The instrument cluster display
will display the set speed.
If the system is set when the vehicle speed is
below 19 mph (30 km/h), the set speed shall be defaulted to 19 mph (30 km/h). If the
system is set when the vehicle speed is
above 19 mph (30 km/h), the set speed shall
be the current speed of the vehicle.
NOTE:
ACC cannot be set if there is a stationary
vehicle in front of your vehicle in close prox -
imity.
Remove your foot from the accelerator pedal.
If you do not, the vehicle may continue to
accelerate beyond the set speed. If this
occurs:
The message “DRIVER OVERRIDE” will
display in the instrument cluster display.
The system will not be controlling the
distance between your vehicle and the
vehicle ahead. The vehicle speed will only
be determined by the position of the
accelerator pedal.
To Resume
If there is a set speed in memory push the
RES (resume) button and then remove your
foot from the accelerator pedal. The instru -
ment cluster display will display the last set
speed.
NOTE:
If your vehicle stays at standstill for longer
than two seconds, then the system will
cancel and the brake force will be
ramped-out. The driver will have to apply
the brakes to keep the vehicle at a stand -
still.
ACC cannot be resumed if there is a
stationary vehicle in-front of your vehicle
in close proximity.
To Vary The Speed Setting
To Increase Speed
While ACC is set, you can increase the set
speed by pushing the SET (+) button.
The driver's preferred units can be selected
through the instrument panel settings. Refer
to “Getting To Know Your Instrument Panel”
in the Owner’s Manual for more information.
The speed increment shown is dependent on
the chosen speed unit of U.S. (mph) or
Metric (km/h):
U.S. Speed (mph)
Pushing the SET (+) button once will
result in a 1 mph increase in set speed.
Each subsequent tap of the button results
in an increase of 1 mph.
If the button is continually pushed, the set
speed will continue to increase in 5 mph
increments until the button is released.
The increase in set speed is reflected in
the instrument cluster display. WARNING!
The Resume function should only be used
if traffic and road conditions permit.
Resuming a set speed that is too high or
too low for prevailing traffic and road
conditions could cause the vehicle to
accelerate or decelerate too sharply for
safe operation. Failure to follow these
warnings can result in a collision and
death or serious personal injury.
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STARTING AND OPERATING
160
Metric Speed (km/h)
Pushing the SET (+) button once will
result in a 1 km/h increase in set speed.
Each subsequent tap of the button results
in an increase of 1 km/h.
If the button is continually pushed, the set
speed will continue to increase in 10 km/
h increments until the button is released.
The increase in set speed is reflected in
the instrument cluster display.
To Decrease Speed
While ACC is set, the set speed can be
decreased by pushing the SET (-) button.
The driver's preferred units can be selected
through the instrument panel settings. Refer
to “Getting To Know Your Instrument Panel”
in the Owner’s Manual for more information.
The speed increment shown is dependent on
the chosen speed unit of U.S. (mph) or
Metric (km/h):
U.S. Speed (mph)
Pushing the SET (-) button once will result
in a 1 mph decrease in set speed. Each
subsequent tap of the button results in a
decrease of 1 mph.
If the button is continually pushed, the set
speed will continue to decrease in 5 mph
decrements until the button is released.
The decrease in set speed is reflected in
the instrument cluster display.
Metric Speed (km/h)
Pushing the SET (-) button once will result
in a 1 km/h decrease in set speed. Each
subsequent tap of the button results in a
decrease of 1 km/h.
If the button is continually pushed, the set
speed will continue to decrease in 10 km/
h decrements until the button is released.
The decrease in set speed is reflected in
the instrument cluster display.
NOTE:
When you override and push the SET (+)
button or SET (-) buttons, the new set
speed will be the current speed of the
vehicle.
When you use the SET (-) button to decel -
erate, if the engine’s braking power does
not slow the vehicle sufficiently to reach
the set speed, the brake system will auto-
matically slow the vehicle.
The ACC system applies the brake down to
a full stop when following a target vehicle.
If an ACC host vehicle follows a target
vehicle to a standstill, the host vehicle will
release the vehicle brakes two seconds
after coming to a full stop.
The ACC system maintains set speed when
driving uphill and downhill. However, a
slight speed change on moderate hills is
normal. In addition, downshifting may
occur while climbing uphill or descending
downhill. This is normal operation and
necessary to maintain set speed. When
driving uphill and downhill, the ACC
system will cancel if the braking tempera-
ture exceeds normal range (overheated).
Setting The Following Distance In ACC
The specified following distance for ACC can
be set by varying the distance setting
between four bars (longest), three bars
(long), two bars (medium) and one bar
(short). Using this distance setting and the
vehicle speed, ACC calculates and sets the
distance to the vehicle ahead. This distance
setting displays in the instrument cluster
display.
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175
Curb Weight
The curb weight of a vehicle is defined as the
total weight of the vehicle with all fluids,
including vehicle fuel, at full capacity condi-
tions, and with no occupants or cargo loaded
into the vehicle. The front and rear curb
weight values are determined by weighing
your vehicle on a commercial scale before
any occupants or cargo are added.
Loading
The actual total weight and the weight of the
front and rear of your vehicle at the ground
can best be determined by weighing it when
it is loaded and ready for operation. The entire vehicle should first be weighed on
a commercial scale to ensure that the GVWR
has not been exceeded. The weight on the
front and rear of the vehicle should then be
determined separately to be sure that the
load is properly distributed over the front and
rear axle. Weighing the vehicle may show
that the GAWR of either the front or rear
axles has been exceeded but the total load is
within the specified GVWR. If so, weight
must be shifted from front to rear or rear to
front as appropriate until the specified
weight limitations are met. Store the heavier
items down low and be sure that the weight
is distributed equally. Stow all loose items
securely before driving.Improper weight distributions can have an
adverse effect on the way your vehicle steers
and handles and the way the brakes operate.
TRAILER TOWING
Trailer Towing Weights (Maximum Trailer Weight Ratings)
CAUTION!
Do not load your vehicle any heavier than
the GVWR or the maximum front and rear
GAWR. If you do, parts on your vehicle can
break, or it can change the way your
vehicle handles. This could cause you to
lose control. Also overloading can shorten
the life of your vehicle.
Model
Frontal AreaMax. GTW (Gross Trailer
Wt.) With Trailer Brakes Max. Trailer Tongue Wt. (See Note)
Two–Door
20 ft2 (1.86 m2)3,300 lb (1,497 kg)
165 lb (75 kg)
Four–Door 30 ft
2 (2.79 m2)5,500 lbs (2,495 kg)
275 lbs (125 kg)
When towing a trailer, the technically permissible laden weight may be exceeded by not more than 10% or 220 lbs (100 kg), whichever is
lower provided the operating speed is restricted to 62 mph (100 km/h) or less. Trailer sway control device is recommended when towing
more than 1,000 lbs (454 kg).
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