light JEEP GRAND CHEROKEE TRAILHAWK 2017 User Guide

ONBOARD DIAGNOSTIC SYSTEM — OBD II
Your vehicle is equipped with a sophisticated Onboard
Diagnostic system called OBD II. This system monitors the
performance of the emissions, engine, and transmission
control systems. When these systems are operating prop-
erly, your vehicle will provide excellent performance and
fuel economy, as well as engine emissions well within
current government regulations.
If any of these systems require service, the OBD II system
will turn on the Malfunction Indicator Light (MIL). It will
also store diagnostic codes and other information to assist
your service technician in making repairs. Although your
vehicle will usually be drivable and not need towing, see
your authorized dealer for service as soon as possible.

SAFETY FEATURES
Anti-Lock Brake System (ABS)
The Anti-Lock Brake System (ABS) provides increased
vehicle stability and brake performance under most brak-
ing 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 activa-
tion(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!(Continued)
•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. Modifica-
tion 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” remains on or
comes on while driving, it indicates that the anti-lock
portion of the brake system is not functioning and that
service is required. However, the conventional brake sys-
tem will continue to operate normally if the “Brake System
Warning Light” is not 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 Elec-
tronic Brake Force Distribution (EBD), Anti-Lock Brake
System (ABS), Brake Assist System (BAS), Hill Start Assist
(HSA), Traction Control System (TCS), Electronic 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), Dynamic Steering Torque (DST), Hill De-
scent Control (HDC), and Selec-Speed Control (SSC).
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 before 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.
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SAFETY 179

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 re-
quired. 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 sys-
tem detects an emergency 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
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.

4. Start the engine.
5. Rotate the steering wheel slightly more than one-halfturn to the left.
6. Push the “ESC Off” button located in the lower switch bank below the climate control four times within 20
seconds. The “ESC Off Indicator Light” should turn on
and turn off two times.
7. Rotate the steering wheel back to center and then an additional slightly more than one-half turn to the right.
8. Turn the ignition to the OFF mode and then back to ON. If the sequence was completed properly, the “ESC Off
Indicator Light” will blink several times to confirm HSA
is disabled.
9. Repeat these steps if you want to return this feature to its previous setting.
Towing With HSA
HSA will also provide assistance to mitigate roll back while
towing a trailer.

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 enabled 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 apply-
ing the brake of the appropriate wheel(s) to assist in
counteracting the oversteer or understeer condition. En-
gine 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” 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.

WARNING!(Continued)
•Vehicle modifications, or failure to properly main-
tain your vehicle, may change the handling charac-
teristics of your vehicle, and may negatively affect
the performance of the ESC system. Changes to the
steering system, suspension, braking system, tire
type and size or wheel size may adversely affect ESC
performance. Improperly inflated and unevenly
worn tires may also degrade ESC performance. Any
vehicle modification or poor vehicle maintenance
that reduces the effectiveness of the ESC system can
increase the risk of loss of vehicle control, vehicle
rollover, personal injury and death.
ESC Operating Modes
NOTE: Depending upon model and mode of operation, the
ESC system may have multiple operating modes.
ESC On
This is the normal operating mode for the ESC. Whenever
the vehicle is started, the ESC system will be in this mode.
This mode should be used for most driving conditions.
Alternate ESC modes should only be used for specific
reasons as noted in the following paragraphs. Partial Off
The “Partial Off” mode is intended for times when a more
spirited driving experience is desired. This mode may
modify TCS and ESC thresholds for activation, which
allows for more wheel spin than normally allowed. This
mode may be useful if the vehicle becomes stuck.
To enter the “Partial Off” mode, momentarily push the
“ESC Off” switch and the “ESC Off Indicator Light” will
illuminate. To turn the ESC on again, momentarily push
the “ESC Off” switch and the “ESC Off Indicator Light”
will turn off.
NOTE:
For vehicles with multiple partial ESC modes a
momentary button push will toggle the ESC mode. Mul-
tiple momentary button pushed may be required to return
to ESC On.

WARNING!(Continued)
feature of TCS is disabled, and the enhanced vehicle
stability offered by the ESC system is reduced.
• Trailer Sway control (TSC) is disabled when the ESC
system is in the “Partial Off” mode.
Full Off — If Equipped
This mode is intended for off-highway or off-road use only
and should not be used on any public roadways. In this
mode, TCS and ESC features are turned OFF. To enter the
“Full Off” mode, push and hold the “ESC Off” switch for five
seconds while the vehicle is stopped with the engine run-
ning. After five seconds, a chime will sound, the “ESC Off
Indicator Light” will illuminate, and the “ESC OFF” message
will display in the instrument cluster. To turn ESC ON again,
momentarily push the “ESC Off” switch.
NOTE: System may switch from ESC “Full Off” to “Partial
Off” mode when vehicle exceeds a predetermined speed.
When the vehicle speed slows below the predetermined
speed the system will return to ESC “Full Off”.
“Full Off” can only be achieved in Track Mode if so
equipped.
ESC modes may also be affected by drive modes if so
equipped.

Enhanced Accident Response System
In the event of an impact, if the communication network
remains intact, and the power remains intact, depending
on the nature of the event, the ORC will determine whether
to have the Enhanced Accident Response System perform
the following functions:
•Cut off fuel to the engine.
• Flash hazard lights as long as the battery has power or
until the hazard light button is pressed. The hazard
lights can be deactivated by pressing the hazard light
button.
• Turn on the interior lights, which remain on as long as
the battery has power.
• Unlock the power door locks.
Enhanced Accident Response System Reset
Procedure
In order to reset the Enhanced Accident Response System
functions after an event, the ignition switch must be
changed from ignition START or ON/RUN to ignition OFF.
Carefully check the vehicle for fuel leaks in the engine
compartment and on the ground near the engine compart-
ment and fuel tank before resetting the system and starting
the engine.
Maintaining Your Air Bag System

have the system inspected at an authorized dealer as
soon as possible. This light will illuminate with a single
chime when a fault with the Air Bag Warning Light has
been detected, it will stay on until the fault is cleared. If
the light comes on intermittently or remains on while
driving, have an authorized dealer service the vehicle
immediately. Refer to “Occupant Restraint Systems” in
“Safety” for further information.
Defroster
Check operation by selecting the defrost mode and place
the blower control on high speed. You should be able to
feel the air directed against the windshield. See your
authorized dealer for service if your defroster is inoper-
able.
Floor Mat Safety Information
Always use floor mats designed to fit your vehicle. Only
use a floor mat that does not interfere with the operation of
the pedal assemblies. Only use a floor mat that is securely
attached using the floor mat fasteners so it cannot slip out
of position and interfere with the pedal assemblies or
impair safe operation of your vehicle in other ways.