Brake JEEP WRANGLER 2012 JK / 3.G Service Manual

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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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 notreduce 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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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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(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.5
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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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Inflation Pressure
This is the cold tire inflation pressure for your vehicle for
all loading conditions up to full GAWR.
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 conditions, 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 commer-
cial scale to ensure that the GVWR has not been ex-
ceeded. 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 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 affect
on the way your vehicle steers and handles, and the way
the brakes operate.
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Weight-Carrying Hitch
A weight-carrying hitch supports the trailer tongue
weight, just as if it were luggage located at a hitch ball or
some other connecting point of the vehicle. This kind of
hitch is the most popular on the market today and is
commonly used to tow small and medium-sized trailers.
Weight-Distributing Hitch
A weight-distributing hitch system works by applying
leverage through spring (load) bars. It is typically used
for heavier loads, to distribute trailer tongue weight to
the tow vehicle’s front axle and the trailer axle(s). When
used in accordance with the manufacturers’ directions, it
provides for a more level ride, offering more consistent
steering and brake control thereby enhancing towing
safety. The addition of a friction/hydraulic sway control
also dampens sway caused by traffic and crosswinds,
and contributes positively to tow vehicle and trailerstability. Trailer sway control and a weight-distributing
(load-equalizing) hitch are recommended for heavier
tongue weights (TW) and may be required depending on
vehicle and trailer configuration/loading to comply with
Gross Axle Weight Rating (GAWR) requirements.
WARNING!
•An improperly adjusted weight-distributing hitch
system may reduce handling, stability, braking
performance, and could result in a collision.
•Weight-Distributing Hitch Systems may not be
compatible with Surge Brake Couplers. Consult
with your hitch and trailer manufacturer or a
reputable Recreational Vehicle dealer for addi-
tional information.
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