2018 JEEP WRANGLER UNLIMITED brake light

air bag has been detected, it will stay on until
the fault is cleared. If the light is either not on
during startup, stays on, or turns on while
driving, have the system inspected at an
authorized dealer as soon as possible.
— Brake Warning Light
This warning light monitors various brake
functions, including brake fluid level and
parking brake application. If the brake light
turns on it may indicate that the parking
brake is applied, that the brake fluid level is
low, or that there is a problem with the
anti-lock brake system.
If the light remains on when the parking
brake has been disengaged, and the fluid
level is at the full mark on the master cylinder
reservoir, it indicates a possible brake hy-
draulic system malfunction or that a problem
with the Brake Booster has been detected by
the Anti-Lock Brake System (ABS) / Elec-
tronic Stability Control (ESC) system. In this
case, the light will remain on until the condi-
tion has been corrected. If the problem is
related to the brake booster, the ABS pump
will run when applying the brake, and a brake
pedal pulsation may be felt during each stop.
The dual brake system provides a reserve brak-
ing capacity in the event of a failure to a portion
of the hydraulic system. A leak in either half of
the dual brake system is indicated by the Brake
Warning Light, which will turn on when the
brake fluid level in the master cylinder has
dropped below a specified level.
The light will remain on until the cause is
corrected.
NOTE:
The light may flash momentarily during sharp
cornering maneuvers, which change fluid
level conditions. The vehicle should have
service performed, and the brake fluid level
checked.
If brake failure is indicated, immediate repair
is necessary.
WARNING!
Driving a vehicle with the red brake light
on is dangerous. Part of the brake system
may have failed. It will take longer to stop
the vehicle. You could have a collision.
Have the vehicle checked immediately.Vehicles equipped with the Anti-Lock Brake
System (ABS) are also equipped with Elec-
tronic Brake Force Distribution (EBD). In the
event of an EBD failure, the Brake Warning
Light will turn on along with the ABS Light.
Immediate repair to the ABS system is re-
quired.
Operation of the Brake Warning Light can be
checked by turning the ignition switch from
the OFF position to the ON/RUN position.
The light should illuminate for approximately
four seconds. The light should then turn off
unless the parking brake is applied or a brake
fault is detected. If the light does not illumi-
nate, have the light inspected by an autho-
rized dealer.
The light also will turn on when the parking
brake is applied with the ignition switch in
the ON/RUN position.
NOTE:
This light shows only that the parking brake is
applied. It does not show the degree of brake
application.
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— Battery Charge Warning Light
This warning light will illuminate when the
battery is not charging properly. If it stays on
while the engine is running, there may be a
malfunction with the charging system. Con-
tact an authorized dealer as soon as possible.
This indicates a possible problem with the
electrical system or a related component.
— Door Open Warning Light
This indicator will illuminate when a door is
ajar/open and not fully closed.
NOTE:
If the vehicle is moving, there will also be a
single chime.
— Electric Power Steering Fault
Warning Light
This warning light will turn on when there's a
fault with the EPS (Electric Power Steering)
system. Refer to “Power Steering” in “Start-
ing And Operating” in the Owner’s Manual for
further information.
WARNING!
Continued operation with reduced assist
could pose a safety risk to yourself and
others. Service should be obtained as soon
as possible.
— Electronic Throttle Control (ETC)
Warning Light
This warning light will illuminate to indicate
a problem with the Electronic Throttle Con-
trol (ETC) system. If a problem is detected
while the vehicle is running, the light will
either stay on or flash depending on the
nature of the problem. Cycle the ignition
when the vehicle is safely and completely
stopped and the transmission is placed in the
PARK position. The light should turn off. If
the light remains on with the vehicle running,
your vehicle will usually be drivable; however,
see an authorized dealer for service as soon
as possible.
NOTE:
This light may turn on if the accelerator and
brake pedals are pressed at the same time.If the light continues to flash when the ve-
hicle is running, immediate service is re-
quired and you may experience reduced per-
formance, an elevated/rough idle, or engine
stall and your vehicle may require towing.
The light will come on when the ignition is
placed in the ON/RUN or ACC/ON/RUN posi-
tion and remain on briefly as a bulb check. If
the light does not come on during starting,
have the system checked by an authorized
dealer.
— Engine Coolant Temperature Warn-
ing Light
This warning light warns of an overheated
engine condition. If the engine coolant tem-
perature is too high, this indicator will illumi-
nate and a single chime will sound. If the
temperature reaches the upper limit, a con-
tinuous chime will sound for four minutes or
until the engine is able to cool: whichever
comes first.
If the light turns on while driving, safely pull
over and stop the vehicle. If the A/C system is
on, turn it off. Also, shift the transmission
GETTING TO KNOW YOUR INSTRUMENT PANEL
68

vehicle and run the engine at idle or slightly
faster, with the transmission in PARK or
NEUTRAL, until the light turns off. Once the
light turns off, you may continue to drive
normally.
WARNING!
If you continue operating the vehicle when
the Transmission Temperature Warning
Light is illuminated you could cause the
fluid to boil over, come in contact with hot
engine or exhaust components and cause
a fire.
CAUTION!
Continuous driving with the Transmission
Temperature Warning Light illuminated
will eventually cause severe transmission
damage or transmission failure.
— Vehicle Security Warning Light — If
Equipped
This light will flash at a fast rate for approxi-
mately 15 seconds when the vehicle security
alarm is arming, and then will flash slowly
until the vehicle is disarmed.
Yellow Warning Lights
— Anti-Lock Brake (ABS) Warning
Light
This warning light monitors the Anti-Lock
Brake System (ABS). The light will turn on
when the ignition is placed in the ON/RUN or
ACC/ON/RUN position and may stay on for as
long as four seconds.
If the ABS light remains on or turns on while
driving, then the Anti-Lock portion of the
brake system is not functioning and service is
required as soon as possible. However, the
conventional brake system will continue to
operate normally, assuming the Brake Warn-
ing Light is not also on.If the ABS light does not turn on when the
ignition is placed in the ON/RUN or ACC/ON/
RUN position, have the brake system in-
spected by an authorized dealer.
— Electronic Stability Control (ESC)
Active Warning Light — If Equipped
This warning light will indicate when the
Electronic Stability Control system is Active.
The “ESC Indicator Light” in the instrument
cluster will come on when the ignition is
placed in the ON/RUN or ACC/ON/RUN posi-
tion, and when ESC is activated. It should go
out with the engine running. If the “ESC
Indicator Light” comes on continuously with
the engine running, a malfunction has been
detected in the ESC system. If this warning
light remains on after several ignition cycles,
and the vehicle has been driven several miles
(kilometers) at speeds greater than 30 mph
(48 km/h), see an authorized dealer as soon
as possible to have the problem diagnosed
and corrected.
• The “ESC Off Indicator Light” and the
“ESC Indicator Light” come on momen-
tarily each time the ignition is placed in the
ON/RUN or ACC/ON/RUN position.
GETTING TO KNOW YOUR INSTRUMENT PANEL
70

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 en-
sure 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.
WARNING!
• The ABS contains sophisticated elec-
tronic equipment that may be suscep-
tible to interference caused by improp-
erly installed or high output radio
transmitting equipment. This interfer-
ence 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
efficiency beyond that afforded by the
WARNING!
condition of the vehicle brakes and tires
or the traction afforded.
• The ABS cannot prevent collisions, in-
cluding 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.
ABS is designed to function with the OEM
tires. Modification may result in degraded
ABS performance.
Anti-Lock Brake Warning Light
The yellow “Anti-Lock Brake Warning Light”
will turn on when the ignition is turned to the
ON/RUN mode and may stay on for as long as
four seconds.
If the “Anti-Lock Brake Warning Light” re-
mains 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
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82

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
turned to the ON/RUN mode, have the light
repaired as soon as possible.
Electronic Brake Control System
Your vehicle is equipped with an advanced
Electronic Brake Control system (EBC). This
system includes Electronic Brake Force Dis-
tribution (EBD), Anti-Lock Brake System
(ABS), Brake Assist System (BAS), Hill Start
Assist (HSA), Traction Control System (TCS),
Electronic Stability Control (ESC), and Elec-
tronic Roll Mitigation (ERM). These systems
work together to enhance both vehicle stabil-
ity and control in various driving conditions.Your vehicle may also be equipped with
Trailer Sway Control (TSC), Ready Alert Brak-
ing (RAB), Rain Brake Support (RBS), Dy-
namic Steering Torque (DST), and Hill De-
scent Control (HDC).
Electronic Brake Force Distribution (EBD)
This function manages the distribution of the
braking torque between the front and rear
axles by limiting braking pressure to the rear
axle. This is done to prevent overslip of the
rear wheels to avoid vehicle instability, and to
prevent the rear axle from entering ABS be-
fore the front axle.
Brake System Warning Light
The red “Brake System Warning Light” will
turn on when the ignition is turned to 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 indicates that
the brake system is not functioning properly
and that immediate service is required. If the“Brake System Warning Light” does not
come on when the ignition is turned to the
ON/RUN mode, have the light repaired as
soon as possible.
Brake Assist System (BAS)
The BAS is designed to optimize the vehicle’s
braking capability during emergency braking
maneuvers. The system detects an emer-
gency braking situation by sensing the rate
and amount of brake application and then
applies optimum pressure to the brakes. This
can help reduce braking distances. The BAS
complements the anti-lock brake system
(ABS). Applying the brakes very quickly re-
sults in the best BAS assistance. To receive
the benefit of the system, you must apply
continuous braking pressure during the stop-
ping 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
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WARNING!
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 man-
ner, which could jeopardize the user's
safety or the safety of others.
Hill Start Assist (HSA)
The HSA system is designed to mitigate roll
back from a complete stop while on an in-
cline. 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 up-
hill direction (i.e., vehicle facing uphill is in
forward gear; vehicle backing uphill is in
REVERSE gear).
• HSA will work in REVERSE gear and all
forward gears. The system will not activate
if the transmission is in PARK or NEU-
TRAL. For vehicles equipped with a manual
transmission, if the clutch is pressed, HSA
will remain active.
WARNING!
There may be situations where the Hill
Start Assist (HSA) will not activate and
WARNING!
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 op-
eration 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 warn-
ings can result in a collision or serious
personal injury.
Disabling And Enabling HSA
This feature can be turned on or turned off.
To change the current setting, refer to “In-
strument Cluster Display” in “Getting To
Know Your Instrument Panel” for further in-
formation.
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84

Towing With HSA
HSA will also provide assistance to mitigate
roll back while towing a trailer.
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 roll-
ing down an incline while resuming ac-
celeration, manually activate the trailer
brake or apply more vehicle brake pres-
sure 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.
• Failure to follow these warnings can re-
sult in a collision or serious personal
injury.
Traction Control System (TCS)
This system monitors the amount of wheel
spin of each of the driven wheels. If wheel
spin is detected, the TCS may apply brake
pressure to the spinning wheel(s) and/or re-
duce engine power to provide enhanced ac-
celeration and stability. A feature of the TCS,
Brake Limited Differential (BLD), functions
similar to a limited slip differential and con-
trols the wheel spin across a driven axle. If
one wheel on a driven axle is spinning faster
than the other, the system will apply the
brake of the spinning wheel. This will allow
more engine torque to be applied to the wheel
that is not spinning. BLD may remain en-
abled even if TCS and ESC are in a reduced
mode.
Electronic Stability Control (ESC)
This system enhances directional control and
stability of the vehicle under various driving
conditions. ESC corrects for oversteering or
understeering of the vehicle by applying the
brake of the appropriate wheel(s) to assist in
counteracting the oversteer or understeer
condition. Engine power may also be reduced
to help the vehicle maintain the desired path.ESC uses sensors in the vehicle to determine
the vehicle path intended by the driver and
compares it to the actual path of the vehicle.
When the actual path does not match the
intended path, ESC applies the brake of the
appropriate wheel to assist in counteracting
the oversteer or understeer condition.
• Oversteer — when the vehicle is turning
more than appropriate for the steering
wheel position.
• Understeer — when the vehicle is turning
less than appropriate for the steering wheel
position.
The “ESC Activation/Malfunction Indicator
Light” located in the instrument cluster will
start to flash as soon as the ESC system
becomes active. The “ESC Activation/
Malfunction Indicator Light” also flashes
when the TCS is active. If the “ESC
Activation/Malfunction Indicator Light” be-
gins 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.
85

(kilometers) at speeds greater than 30 mph
(48 km/h), see an authorized dealer as soon
as possible to have the problem diagnosed
and corrected.
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 con-
ditions.
NOTE:
• The “ESC Activation/Malfunction Indicator
Light” and the “ESC OFF Indicator Light”
come on momentarily each time the igni-
tion 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 click-
ing 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” indi-
cates the customer has elected to
have the Electronic Stability Control
(ESC) in a reduced mode.
Electronic Roll Mitigation (ERM)
This system anticipates the potential for
wheel lift by monitoring the driver’s steering
wheel input and the speed of the vehicle.
When ERM determines that the rate of
change of the steering wheel angle and vehi-
cle’s speed are sufficient to potentially cause
wheel lift, it then applies the appropriate
brake and may also reduce engine power to
lessen the chance that wheel lift will occur.
ERM can only reduce the chance of wheel lift
occurring during severe or evasive driving
maneuvers; it cannot prevent wheel lift due
to other factors, such as road conditions,
leaving the roadway, or striking objects or
other vehicles.NOTE:
ERM is disabled anytime the ESC is in “Full
Off” mode (if equipped). Refer to “Electronic
Stability Control (ESC)” in this section for a
complete explanation of the available ESC
modes.
WARNING!
Many factors, such as vehicle loading,
road conditions and driving conditions,
influence the chance that wheel lift or
rollover may occur. ERM cannot prevent
all wheel lift or roll overs, especially those
that involve leaving the roadway or striking
objects or other vehicles. The capabilities
of an ERM-equipped vehicle must never
be exploited in a reckless or dangerous
manner which could jeopardize the user's
safety or the safety of others.
SAFETY
88