Jeep Wrangler Unlimited (2012 year). Instruction

WARNING!

• Never use the PARK position on an automatic

transmission as a substitute for the parking brake.
Always apply the parking brake fully when
parked to guard against vehicle movement and
possible injury or damage.

• When leaving the vehicle, always remove the key

fob from the ignition and lock your vehicle.

• Never leave children alone in a vehicle, or with

access to an unlocked vehicle. Allowing children
to be in a vehicle unattended is dangerous for a
number of reasons. A child or others could be
seriously or fatally injured. Children should be
warned not to touch the parking brake, brake
pedal or the shift lever.

(Continued)

WARNING! (Continued)

• Do not leave the key in or near the vehicle. A child

could operate power windows, other controls, or
move the vehicle.

• Be sure the parking brake is fully disengaged

before driving; failure to do so can lead to brake
failure and a collision.

• Always fully apply the parking brake when leav-

ing your vehicle or it may roll and cause damage or
injury. Also, be certain to leave an automatic
transmission in PARK, a manual transmission in
REVERSE or first gear. Failure to do so may cause
the vehicle to roll and cause damage or injury.

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CAUTION!

If the “Brake Warning Light” remains on with the
parking brake released, a brake system malfunction
is indicated. Have the brake system serviced by an
authorized dealer immediately.

ANTI-LOCK BRAKE SYSTEM
The Anti-Lock Brake System (ABS) is designed to aid the
driver in maintaining vehicle control under adverse
braking conditions. The system operates with a separate
computer to modulate hydraulic pressure to prevent
wheel lock-up and help avoid skidding on slippery
surfaces.

All vehicle wheels and tires must be the same size and
type, and tires must be properly inflated to produce
accurate signals for the computer.

WARNING!

Significant over or under-inflation of tires, or mixing
sizes of tires or wheels on the vehicle can lead to loss
of braking effectiveness.

The Anti-Lock Brake System conducts a low speed self-
test at about 12 mph (20 km/h). If for any reason your
foot is on the brake when the vehicle reaches 12 mph
(20 km/h), this check will be delayed until 25 mph
(40 km/h).

The Anti-Lock Brake System pump motor runs during
the self-test, and during an ABS stop, to provide the
regulated hydraulic pressure. The motor pump makes a
low humming noise during operation; this is normal.

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WARNING!

• 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 Anti-Lock Brake System (ABS) cannot prevent

the natural laws of physics from acting on the
vehicle, nor can they increase braking or steering
efficiency 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 hydro-
planing.

(Continued)

WARNING! (Continued)

• The capabilities of an ABS-equipped vehicle must

never be exploited in a reckless or dangerous
manner which could jeopardize the user’s safety
or the safety of others.

CAUTION!

The Anti-Lock Brake System is subject to possible
detrimental effects of electronic interference caused
by improperly installed aftermarket radios or tele-
phones.

NOTE:

During severe braking conditions, a pulsing

sensation may occur and a clicking noise will be heard.
This is normal, indicating that the Anti-Lock Brake
System is functioning.

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ELECTRONIC BRAKE CONTROL SYSTEM
Your vehicle is equipped with an advanced electronic
brake control system that includes Anti-Lock Brake Sys-
tem (ABS), Traction Control System (TCS), Brake Assist
System (BAS), Hill Start Assist (HSA), Electronic Roll
Mitigation (ERM), Electronic Stability Control (ESC),
Trailer Sway Control (TSC), and Hill Descent Control
(HDC). All of these systems work together to enhance
vehicle stability and control in various driving condi-
tions, and are commonly referred to as ESC.

WARNING!

The Anti-Lock Brake System (ABS) cannot prevent
the natural laws of physics from acting on the ve-
hicle, nor can they increase the traction afforded by
prevailing road conditions. The ABS cannot prevent
collisions, including those resulting from excessive
speed in turns, driving on very slippery surfaces, or
hydroplaning. The capabilities of an ABS-equipped
vehicle must never be exploited in a reckless or
dangerous manner which could jeopardize the user’s
safety or the safety of others.

Traction Control System (TCS)

This system monitors the amount of wheel spin of each of
the driven wheels. If wheel spin is detected, brake
pressure is applied to the slipping wheel(s) to provide
enhanced acceleration and stability. A feature of the TCS
system functions similar to a limited slip differential and

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419

controls 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. This feature remains active even if
TCS and ESC are in either the “Partial Off” or “Full Off”
modes. Refer to “Electronic Stability Control (ESC)” in
this section for further information.

Brake Assist System (BAS)
The BAS is designed to optimize the vehicle’s braking
capability during emergency braking maneuvers. The
system detects an emergency braking situation by sens-
ing 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 results in the best BAS assistance. To receive the
benefit of the system, you must apply continuous brak-
ing pressure during the stopping sequence. 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. The BAS cannot prevent collisions,
including those resulting from excessive speed in
turns, driving on very slippery surfaces, or hydro-
planing. 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.

Hill Start Assist (HSA)
The HSA system is designed to assist the driver when
starting a vehicle from a stop on a hill. HSA will maintain

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the level of brake pressure the driver applied for a short
period of time after the driver takes their foot off of the
brake pedal. If the driver does not apply the throttle
during this short period of time, the system will release
brake pressure and the vehicle will roll down the hill. The
system will release brake pressure in proportion to
amount of throttle applied as the vehicle starts to move in
the intended direction of travel.

WARNING!

If the clutch pedal (manual transmission only) re-
mains pressed during the application of the throttle,
the HSA will disengage allowing the vehicle to roll
down the incline. This could cause a collision with
another vehicle or object. To avoid this, do not apply
throttle while pressing the clutch pedal until you are
ready to release the clutch. Always remember the
driver is responsible for braking the vehicle.

HSA Activation Criteria
The following criteria must be met in order for HSA to
activate:

• Vehicle must be stopped
• Vehicle must be on an 8% or greater incline (3% for

manual transmission equipped vehicles)

• Gear selection matches vehicle uphill direction (i.e.,

vehicle facing uphill is in forward gear; vehicle back-
ing uphill is in REVERSE gear).

WARNING!

There may be situations on minor hills (i.e., less than
8%), with a loaded vehicle, or while pulling a trailer
where the system will not activate and slight rolling
may occur, which could cause a collision with an-
other vehicle or object. Always remember the driver
is responsible for braking the vehicle.

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421

The system will only work if the intended direction of the
vehicle and vehicle gear match. For example, if the
intended direction is forward up a hill and the vehicle is
in DRIVE (automatic transmission equipped vehicle),
and the activation criteria are met, HSA will activate.

HSA On Automatic Transmission Vehicles
The system will work in REVERSE, and all forward gears
on vehicles equipped with an automatic transmission.
The system will not activate if the vehicle is placed in
NEUTRAL.

HSA On Manual Transmission Vehicles
The system will work in REVERSE, forward gears, and
NEUTRAL on manual transmission equipped vehicles.
The system does not recognize NEUTRAL on manual
vehicles, thus it will hold the vehicle on an incline for a
short period while in NEUTRAL, regardless of clutch
position. To prevent this, do not attempt to roll down a
hill simply by putting the transmission in NEUTRAL and
letting gravity act on the vehicle, as the HSA will prevent
the vehicle from rolling. Instead, use the appropriate gear
for moving in the desired direction.

Towing With HSA
HSA will provide assistance when starting on a grade
when pulling a trailer.

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WARNING!

• If you use a trailer brake controller with your

trailer, your trailer brakes may be activated and
deactivated with the brake switch. If so, when the
brake pedal is released there may not be enough
brake pressure to hold the vehicle and trailer on a
hill and this could cause a collision with another
vehicle or object behind you. In order to avoid
rolling down the hill while resuming acceleration,
manually activate the trailer brake prior to releas-
ing the brake pedal. Always remember the driver
is responsible for braking the vehicle.

• HSA is not a parking brake. Always apply the

parking brake fully when leaving your vehicle.
Also, be certain to leave the transmission in PARK.

(Continued)

WARNING! (Continued)

• Failure to follow these warnings may cause the

vehicle to roll down the incline and could collide
with another vehicle, object or person, and cause
serious or fatal injury. Always remember to use the
parking brake while parking on a hill and that the
driver is responsible for braking the vehicle.

NOTE:

The HSA system may also be turned on and off

if the vehicle is equipped with the Electronic Vehicle
Information Center (EVIC). Refer to Electronic Vehicle
Information Center (EVIC) in “Understanding Your In-
strument Panel” for further information.

HSA Off
If you wish to turn off the HSA system, follow this
procedure:

1. Start with the engine off and vehicle in PARK (auto-
matic transmission) or NEUTRAL with clutch out

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423

(manual transmission) with wheels straight. Apply park-
ing brake on manual transmission vehicle.

2. Start the engine.

3. With the engine running, the brake applied, and the
clutch out, rotate the steering wheel 180° counterclock-
wise from center.

4. Press the ESC OFF switch four times within twenty
seconds.

5. Rotate the steering wheel 360° clockwise (180° clock-
wise from center).

6. Cycle ignition switch OFF then ON.

7. If the sequence was completed properly, the “ESC
Activation/Malfunction Indicator Light” will blink sev-
eral times to confirm HSA is off.

Steps 1-7 must be completed within 90 seconds to turn off
HSA. Repeat steps 1-7 to re-enable HSA functionality.

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 vehicle’s speed are
sufficient to potentially cause wheel lift, it applies the
appropriate brake and may reduce engine power to lessen
the chance that wheel lift will occur. ERM will only inter-
vene during very severe or evasive driving maneuvers.

Electronic Roll Mitigation (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 road-
way or striking objects or other vehicles.

NOTE:

Anytime the ESC system is in the “Full Off”

mode, ERM is disabled. Refer to Electronic Stability
Control (ESC) for a complete explanation of the available
ESC modes.

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WARNING!

Many factors, such as vehicle loading, road conditions
and driving conditions, influence the chance that
wheel lift or rollover may occur. Electronic Roll Miti-
gation (ERM) cannot prevent all wheel lift or rollovers,
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.

Electronic Stability Control (ESC)

This system enhances directional control and stability of
the vehicle under various driving conditions. The ESC
corrects for over/under steering of the vehicle by apply-
ing the brake of the appropriate wheel to assist in
counteracting the over/under steer 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 appro-
priate 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” (lo-
cated in the instrument cluster), starts to flash as soon as
the tires lose traction 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 ac-
celeration, 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.

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WARNING!

Electronic Stability Control (ESC) cannot prevent the
natural laws of physics from acting on the vehicle,
nor can it increase the traction afforded by prevailing
road conditions. ESC cannot prevent accidents, in-
cluding those resulting from excessive speed in
turns, driving on very slippery surfaces, or hydro-
planing. ESC also cannot prevent accidents resulting
from loss of vehicle control due to inappropriate
driver input for the conditions. Only a safe, attentive,
and skillful driver can prevent accidents. The capa-
bilities of an ESC equipped vehicle must never be
exploited in a reckless or dangerous manner which
could jeopardize the user’s safety or the safety of
others.

The ESC system has three available operating modes in
4H range. The system has one operating mode in 4L
range. Two-wheel drive vehicles and four-wheel drive
vehicles in 2H range have two operating modes.

4H Range (4WD Models) Or 2WD Models

On
This is the normal operating mode for ESC in 4H and
2WD vehicles.

Partial Off
This mode is entered by momentarily pressing the ESC
OFF switch.

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When in

⬙Partial Off⬙ mode, the TCS portion of ESC has

been disabled and the “ESC Activation/Malfunction
Indicator Light” will be illuminated.

All other stability features of ESC function normally. This
mode is intended to be used if the vehicle is in deep
snow, sand, or gravel conditions and more wheel spin
than ESC would normally allow is required to gain
traction. To turn ESC on again, momentarily press the
ESC OFF switch. This will restore the normal “ESC On”
mode of operation.

NOTE:

To improve the vehicle’s traction when driving

with snow chains, or starting off in deep snow, sand, or
gravel, it may be desirable to switch to the “Partial Off”
mode by pressing the ESC OFF switch. Once the situation
requiring ESC to be switched to the “Partial Off” mode is
overcome, turn ESC back on by momentarily pressing the
ESC OFF switch. This may be done while the vehicle is in
motion.

ESC OFF Switch

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WARNING!

With the ESC switched off, the enhanced vehicle
stability offered by ESC and ERM are unavailable. In
an emergency evasive maneuver, the ESC and ERM
systems will not engage to assist in maintaining
stability. The “Full Off” ESC mode is intended for
off-road use only.

4L Range (4WD Models)

ESC Off
This is the normal operating mode for ESC in 4L range.
Whenever the vehicle is started in 4L range, or the
transfer case (if equipped) is shifted from 4H range or
NEUTRAL to 4L range, the ESC system will be in this
mode. In 4L range, ESC and TCS, except for the “limited

slip” feature described in the TCS section, are turned off
until the vehicle reaches a speed of 40 mph (64 km/h). At
40 mph (64 km/h), the normal ESC stability function
returns but TCS remains off. When the vehicle speed
drops below 35 mph (56 km/h), the ESC system shuts off.
The ESC is off at low vehicle speeds in 4L range so that it
will not interfere with off-road driving, but the ESC
function returns to provide the stability feature at speeds
above 40 mph (64 km/h). The “ESC Activation/
Malfunction Indicator Light” will always be illuminated
in 4L range when ESC is off.

NOTE:

The “ESC OFF” message will display and the

audible chime will sound when the shift lever is placed in
the PARK position from any position other than PARK,
and then moved out of the PARK position. This will
occur even if the message was previously cleared.

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WARNING!

ESC Activation/Malfunction Indicator Light And
ESC OFF Indicator Light

The “ESC Activation/Malfunction Indicator
Light” in the instrument cluster will come on
when the ignition switch is turned to the ON
position. It should go out with the engine

running. If the “ESC Activation/Malfunction Indicator
Light” comes on continuously with the engine running, a
malfunction has been detected in the ESC system. If this
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 your autho-
rized dealer as soon as possible to have the problem
diagnosed and corrected.

The “ESC Activation/Malfunction Indicator Light” (lo-
cated in the instrument cluster) starts to flash as soon as
the tires lose traction 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 ac-
celeration, 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 Indicator Light”

and the “ESC OFF Indicator Light” come on momen-
tarily each time the ignition switch is turned ON.

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• 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
Electronic Stability Control (ESC) is off.

Trailer Sway Control (TSC)
TSC uses sensors in the vehicle to recognize an exces-
sively swaying trailer and will take the appropriate
actions to attempt to stop the sway. The system may
reduce engine power and apply the brake of the appro-
priate wheel(s) to counteract the sway of the trailer. TSC
will become active automatically once an excessively

swaying trailer is recognized. No driver action is re-
quired. Note that TSC cannot stop all trailers from
swaying. Always use caution when towing a trailer and
follow the tongue weight recommendations. Refer to
“Trailer Towing” in “Starting and Operating” for further
information. When TSC is functioning, the “ESC
Activation/Malfunction Indicator Light” will flash, the
engine power may be reduced and you may feel the
brakes being applied to individual wheels to attempt to
stop the trailer from swaying. TSC is disabled when the
ESP system is in the “Partial Off” or “Full Off” modes.

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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Hill Descent Control (HDC) – If Equipped
HDC is only intended for low speed off-road driving.
HDC maintains vehicle speed while descending hills in
off-road driving conditions by applying the brakes when
necessary.

The symbol indicates the status of the Hill
Descent Control (HDC) feature. The lamp will
be on solid when HDC is armed. HDC can only
be armed when the transfer case is in the “4WD

LOW” position and the vehicle speed is less then 30 mph
(48 km/h). If these conditions are not met while attempt-
ing to use the HDC feature, the HDC indicator light will
flash on/off.

When enabled, HDC senses the terrain and activates
when the vehicle is descending a hill. HDC speed may be
adjusted by the driver to suit the driving conditions. The
speed corresponds to the transmission gear selected.

Gear

Approximate HDC Set
Speed

1st

1 mph (1.5 km/h)

2nd

2.5 mph (4 km/h)

3rd

4 mph (6.5 km/h)

4th

5.5 mph (9 km/h)

DRIVE

7.5 mph (12 km/h)

REVERSE

1 mph (1.5 km/h)

However, the driver can override HDC operation by
applying the brake to slow the vehicle down below the
HDC control speed. If more speed is desired during HDC
control, the accelerator pedal will increase vehicle speed
in the usual manner. When either the brake or the
accelerator is released, HDC will control the vehicle at the
original set speed.

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Jeep Wrangler Unlimited (2012 year). Instruction - part 27