2015 JEEP GRAND CHEROKEE wheel size

On the other hand, depending on the type and location of
impact, Advanced Front Air Bags may deploy in crashes
with little vehicle front-end damage but that produce a
severe initial deceleration.
Because air bag sensors measure vehicle deceleration
over time, vehicle speed and damage by themselves are
not good indicators of whether or not an air bag should
have deployed.
Seat belts are necessary for your protection in all colli-
sions, and also are needed to help keep you in position,
away from an inflating air bag.
When the ORC detects a collision requiring the Ad-
vanced Front Air Bags, it signals the inflator units. A large
quantity of non-toxic gas is generated to inflate the
Advanced Front Air Bags.
The steering wheel hub trim cover and the upper right
side of the instrument panel separate and fold out of the
way as the air bags inflate to their full size. The Advanced
Front Air Bags fully inflate in less time than it takes to
blink your eyes. The air bags then quickly deflate while
helping to restrain the driver and front passenger.
Knee Impact Bolsters
The Knee Impact Bolsters help protect the knees of the
driver and front passenger, and position the front occu-
pants for improved interaction with the Advanced Front
Air Bags.
WARNING!
•Do not drill, cut, or tamper with the knee impact
bolsters in any way.
•Do not mount any accessories to the knee impact
bolsters such as alarm lights, stereos, citizen band
radios, etc.
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THINGS TO KNOW BEFORE STARTING YOUR VEHICLE 71

NOTE:Any chassis/suspension or tire size modifications
to the vehicle will effect the performance of the Adaptive
Cruise Control and Forward Collision Warning System.
Activating Adaptive Cruise Control (ACC)
You can only engage ACC if the vehicle speed is above
0 mph (0 km/h).
The minimum Set Speed for the ACC system is 20 mph
(32 km/h).
When the system is turned on and in the READY state,
the Driver Information Display (DID) displays “ACC
Ready.”
When the system is OFF, the DID displays “Adaptive
Cruise Control (ACC) Off.”
NOTE:You cannot engage ACC under the following
conditions:
•When in Four-Wheel Drive Low.
•When you apply the brakes.
•When the parking brake is set.
•When the automatic transmission is in PARK, RE-
VERSE or NEUTRAL.
•When the Vehicle speed is outside of the speed range.
•When the brakes are overheated.
•When the driver door is open.
•When the driver seat belt is unbuckled.
To Activate/Deactivate
Push and release the Adaptive Cruise Control (ACC)
ON/OFF button. The ACC menu in the DID displays
“ACC Ready.”
196 UNDERSTANDING THE FEATURES OF YOUR VEHICLE

Your vehicle has also been equipped with a TPMS
malfunction indicator to indicate when the system is not
operating properly. The TPMS malfunction indicator is
combined with the low tire pressure telltale. When the
system detects a malfunction, the telltale will flash for
approximately one minute and then remain continuously
illuminated. This sequence will continue upon subse-
quent vehicle start-ups as long as the malfunction exists.
When the malfunction indicator is illuminated, the sys-
tem may not be able to detect or signal low tire pressure
as intended. TPMS malfunctions may occur for a variety
of reasons, including the installation of replacement or
alternate tires or wheels on the vehicle that prevent the
TPMS from functioning properly. Always check the
TPMS malfunction telltale after replacing one or more
tires or wheels on your vehicle, to ensure that the
replacement or alternate tires and wheels allow the TPMS
to continue to function properly.
CAUTION!
The TPMS has been optimized for the original
equipment tires and wheels. TPMS pressures and
warning have been established for the tire size
equipped on your vehicle. Undesirable system opera-
tion or sensor damage may result when using re-
placement equipment that is not of the same size,
type, and/or style. Aftermarket wheels can cause
sensor damage. Do not use tire sealant from a can or
balance beads if your vehicle is equipped with a
TPMS, as damage to the sensors may result.
15. Driver Information Display (DID)
The odometer display shows the total distance the ve-
hicle has been driven.
U.S. Federal regulations require that upon transfer of
vehicle ownership, the seller certify to the purchaser the
correct mileage that the vehicle has been driven. If your
298 UNDERSTANDING YOUR INSTRUMENT PANEL

the same speed. The 4WD LOW position is intended for
loose, slippery road surfaces only. Driving in the 4WD
LOW position on dry, hard-surfaced roads may cause
increased tire wear and damage to driveline components.
When operating your vehicle in 4WD LOW, the engine
speed is approximately three times that of the 4WD HI
position at a given road speed. Take care not to overspeed
the engine and do not exceed 25 mph (40 km/h).
Proper operation of four-wheel drive vehicles depends
on tires of equal size, type, and circumference on each
wheel. Any difference will adversely affect shifting and
cause damage to the transfer case.
Because four-wheel drive provides improved traction,
there is a tendency to exceed safe turning and stopping
speeds. Do not go faster than road conditions permit.
WARNING!
You or others could be injured or killed if you leave
the vehicle unattended with the transfer case in the
NEUTRAL position without first fully engaging the
parking brake. The transfer case NEUTRAL position
disengages both the front and rear drive shafts from
the powertrain and will allow the vehicle to roll,
even if the transmission is in PARK. The parking
brake should always be applied when the driver is
not in the vehicle.
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In the event power assist is lost for any reason (i.e.,
repeated brake applications with the engine off) the
brakes will still function. However, the effort required to
brake the vehicle will be much greater than that required
with the power system operating.
ELECTRONIC BRAKE CONTROL SYSTEM
Your vehicle is equipped with an advanced electronic
brake control system that includes the Anti-Lock Brake
System (ABS), Traction Control System (TCS), Brake
Assist System (BAS), Electronic Roll Mitigation (ERM),
and Electronic Stability Control (ESC). All five of these
systems work together to enhance vehicle stability and
control in various driving conditions.
Also, your vehicle may be equipped with Trailer Sway
Control (TSC), Hill Start Assist (HSA), Ready Alert
Braking (RAB), Rain Brake Support (RBS) and, if it has
four-wheel drive with the MP 3023 two-speed transfer
case, Hill Descent Control (HDC), Selec Speed Control
(SSC).
Anti-Lock Brake System (ABS)
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.
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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.
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 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.
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equipment tire and wheel found on the front or rear axle
of your vehicle. This spare tire may be used in the tire
rotation for your vehicle. If your vehicle has this option,
refer to an authorized tire dealer for the recommended
tire rotation pattern.
Compact Spare Tire — If Equipped
The compact spare is for temporary emergency use only.
You can identify if your vehicle is equipped with a
compact spare by looking at the spare tire description on
the Tire and Loading Information Placard located on the
driver ’s side door opening or on the sidewall of the tire.
Compact spare tire descriptions begin with the letter “T”
or “S” preceding the size designation. Example: T145/
80D18 103M.
T, S = Temporary Spare Tire
Since this tire has limited tread life, the original equip-
ment tire should be repaired (or replaced) and reinstalled
on your vehicle at the first opportunity.
Do not install a wheel cover or attempt to mount a
conventional tire on the compact spare wheel, since the
wheel is designed specifically for the compact spare tire.
Do not install more than one compact spare tire and
wheel on the vehicle at any given time.
WARNING!
Compact spares are for temporary emergency use
only. With these spares, do not drive more than
50 mph (80 km/h). Temporary use spares have limited
tread life. When the tread is worn to the tread wear
indicators, the temporary use spare tire needs to be
replaced. Be sure to follow the warnings, which
apply to your spare. Failure to do so could result in
spare tire failure and loss of vehicle control.
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Full Size Spare — If Equipped
The full size spare is for temporary emergency use only.
This tire may look like the originally equipped tire on the
front or rear axle of your vehicle, but it is not. This spare
tire may have limited tread life. When the tread is worn
to the tread wear indicators, the temporary use full size
spare tire needs to be replaced. Since it is not the same as
your original equipment tire, replace (or repair) the
original equipment tire and reinstall on the vehicle at the
first opportunity.
Limited-Use Spare — If Equipped
The limited-use spare tire is for temporary emergency
use only. This tire is identified by a label located on the
limited-use spare wheel. This label contains the driving
limitations for this spare. This tire may look like the
original equipped tire on the front or rear axle of your
vehicle, but it is not. Installation of this limited-use spare
tire affects vehicle handling. Since it is not the same as
your original equipment tire, replace (or repair) the
original equipment tire and reinstall on the vehicle at the
first opportunity.
WARNING!
Limited-use spares are for emergency use only. In-
stallation of this limited-use spare tire affects vehicle
handling. With this tire, do not drive more than the
speed listed on the limit-use spare wheel. Keep
inflated to the cold tire inflation pressures listed on
your Tire and Loading Information Placard located
on the driver ’s side B-Pillar or the rear edge of the
driver ’s side door. Replace (or repair) the original
equipment tire at the first opportunity and reinstall it
on your vehicle. Failure to do so could result in loss
of vehicle control.
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