2018 JEEP GRAND CHEROKEE LIMITED Owners Manual

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
an authorized dealer for service as soon as possible.

WARNING!(Continued)
vehicle control could occur that may result in an
accident involving serious injury or death.
• Access, or allow others to access, information
stored in your vehicle systems, including personal
information.
For further information, refer to “Cybersecurity” in “Mul-
timedia”.
EMISSIONS INSPECTION AND MAINTENANCE
PROGRAMS
In some localities, it may be a legal requirement to pass an
inspection of your vehicle’s emissions control system.
Failure to pass could prevent vehicle registration. For states that require an Inspection and Main-
tenance (I/M), this check verifies the “Malfunc-
tion Indicator Light (MIL)” is functioning and is
not on when the engine is running, and that the
OBD II system is ready for testing.
Normally, the OBD II system will be ready. The OBD II
system may notbe ready if your vehicle was recently
serviced, recently had a dead battery or a battery replace- ment. If the OBD II system should be determined not ready
for the I/M test, your vehicle may fail the test.
Your vehicle has a simple ignition actuated test, which you
can use prior to going to the test station. To check if your
vehicle’s OBD II system is ready, you must do the follow-
ing:
1. Cycle the ignition switch to the ON position, but do not
crank or start the engine.
NOTE: If you crank or start the engine, you will have to
start this test over.
2. As soon as you cycle the ignition switch to the ON position, you will see the “Malfunction Indicator Light
(MIL)” symbol come on as part of a normal bulb check.
3. Approximately 15 seconds later, one of two things will happen:
• The MIL will flash for about ten seconds and then return
to being fully illuminated until you turn OFF the igni-
tion or start the engine. This means that your vehicle’s
OBD II system is not readyand you should notproceed
to the I/M station.
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GETTING TO KNOW YOUR INSTRUMENT PANEL 161

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 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!(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 “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 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 165

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.