2012 JEEP GRAND CHEROKEE temperature

CAUTION!
After inspecting or adjusting the tire pressure, al-
ways reinstall the valve stem cap. This will prevent
moisture and dirt from entering the valve stem,
which could damage it.
Inflation pressures specified on the placard are always
cold tire inflation pressure. Cold tire inflation pressure is
defined as the tire pressure after the vehicle has not been
driven for at least three hours, or driven less than 1 mile
(1.6 km) after a three-hour period. The cold tire inflation
pressure must not exceed the maximum inflation pres-
sure molded into the tire sidewall.
Check tire pressures more often if subject to a wide range
of outdoor temperatures, as tire pressures vary with
temperature changes. Tire pressures change by approximately 1 psi (7 kPa) per
12°F (7°C) of air temperature change. Keep this in mind
when checking tire pressure inside a garage, especially in
the winter.
Example: If garage temperature = 68°F (20°C) and the
outside temperature = 32°F (0°C) then the cold tire
inflation pressure should be increased by 3 psi (21 kPa),
which equals 1 psi (7 kPa) for every 12°F (7°C) for this
outside temperature condition.
Tire pressure may increase from 2 to 6 psi (13 to 40 kPa)
during operation. DO NOT reduce this normal pressure
build-up, or your tire pressure will be too low.
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These effects can be reduced by timely rotation of tires.
The benefits of rotation are especially worthwhile with
aggressive tread designs such as those on On/Off-Road
type tires. Rotation will increase tread life, help to main-
tain mud, snow, and wet traction levels, and contribute to
a smooth, quiet ride.
Refer to the “Maintenance Schedule” for the proper
maintenance intervals. More frequent rotation is permis-
sible if desired. The reasons for any rapid or unusual
wear should be corrected prior to rotation being per-
formed.
NOTE:The premium Tire Pressure Monitor System will
automatically locate the pressure values displayed in the
correct vehicle position following a tire rotation.
The suggested rotation method is the “forward-cross”
shown in the following diagram.
TIRE PRESSURE MONITOR SYSTEM (TPMS)
The Tire Pressure Monitoring System (TPMS) will warn
the driver of a low tire pressure based on the vehicle
recommended cold tire placard pressure.
The tire pressure will vary with temperature by about
1 psi (7 kPa) for every 12°F (6.5°C). This means that when
Tire Rotation
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the outside temperature decreases, the tire pressure will
decrease. Tire pressure should always be set based on
cold inflation tire pressure. This is defined as the tire
pressure after the vehicle has not been driven for at least
three hours, or driven less than 1 mile (1.6 km) after a
three-hour period.Refer to “Tires – General Informa-
tion” in “Starting and Operating” for information on
how to properly inflate the vehicle’s tires. The tire
pressure will also increase as the vehicle is driven - this is
normal and there should be no adjustment for this
increased pressure.
The TPMS will warn the driver of a low tire pressure if
the tire pressure falls below the low pressure warning
threshold for any reason, including low temperature
effects, or natural pressure loss through the tire.
The TPMS will continue to warn the driver of low tire
pressure as long as the condition exists, and will not turn
off until the tire pressure is at or above recommended cold tire placard pressure. Once the low tire pressure
warning has been illuminated, the tire pressure must be
increased to the recommended cold tire pressure in order
for the Tire Pressure Monitoring Telltale Light to be
turned off. The system will automatically update and the
Tire Pressure Monitoring Telltale Light will extinguish
once the updated tire pressures have been received. The
vehicle may need to be driven for up to 20 minutes above
15 mph (24 km/h) to receive this information.
For example, your vehicle has a recommended cold
(parked for more than three hours) tire placard pressure
of 33 psi (227 kPa). If the ambient temperature is 68°F
(20°C) and the measured tire pressure is 28 psi (193 kPa),
a temperature drop to 20°F (-7°C) will decrease the tire
pressure to approximately 24 psi (165 kPa). This tire
pressure is sufficiently low enough to turn ON the Tire
Pressure Monitoring Telltale Light. Driving the vehicle
may cause the tire pressure to rise to approximately
28 psi (193 kPa), but the Tire Pressure Monitoring Telltale
500 STARTING AND OPERATING

•The TPMS is not a substitute for proper tire mainte-
nance, and it is the driver ’s responsibility to maintain
correct tire pressure using an accurate tire gauge, even
if under-inflation has not reached the level to trigger
illumination of the Tire Pressure Monitoring Telltale
Light.
•Seasonal temperature changes will affect tire pressure,
and the TPMS will monitor the actual tire pressure in
the tire.
Base System
The Tire Pressure Monitor System (TPMS) uses wireless
technology with wheel rim-mounted electronic sensors to
monitor tire pressure levels. Sensors, mounted to each
wheel as part of the valve stem, transmit tire pressure
readings to the Receiver Module.
NOTE:It is particularly important, for you to regularly
check the tire pressure in all of your tires, and to maintain
the proper pressure. The TPMS consists of the following components:
•Receiver Module
•Four Tire Pressure Monitoring Sensors
•Tire Pressure Monitoring Telltale Light
A low spare tire will not cause the Tire Pressure Moni-
toring Telltale Light to illuminate, a warning message to
appear, or the chime to sound. The Tire Pressure Monitoring Telltale Light will
illuminate in the instrument cluster, a “LOW TIRE
PRESSURE” message will display in the instru-
ment cluster for 5 seconds, and an audible chime will be
activated, when one or more of the four active road tire
pressures are low. Should this occur, you should stop as
soon as possible, check the inflation pressure of each tire
on your vehicle, and inflate each tire to the vehicle’s
recommended cold placard pressure value. The system
502 STARTING AND OPERATING

Ethanol Fuel (E-85)
E-85 is a mixture of approximately 85% fuel ethanol and
15% unleaded gasoline.
WARNING!
Ethanol vapors are extremely flammable and could
cause serious personal injury. Never have any smok-
ing materials lit in or near the vehicle when remov-
ing the fuel filler tube cap (gas cap) or filling the
tank. Do not use E-85 as a cleaning agent and never
use it near an open flame.
Fuel Requirements
Your vehicle will operate on both unleaded gasoline with
an octane rating of 87, or E-85 fuel, or any mixture of
these two. For best results, a refueling pattern that
alternates between E-85 and unleaded gasoline should be
avoided.When you do switch fuel types it is recommended that:
•you do not switch when the fuel gauge indicates less
than 1/4 full
•you do not add less than 5 gallons (19 Liters) when
refueling
•you operate the vehicle immediately after refueling for
a period of at least 5 minutes
Observing these precautions will avoid possible hard
starting and/or significant deterioration in driveability
during warm up.
NOTE:
•When the ambient temperature is above 90° F (32° C),
you may experience hard starting and rough idle
following start up even if the above recommendations
are followed.
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STARTING AND OPERATING 515

•Some additives used in regular gasoline are not fully
compatible with E-85 and may form deposits in your
engine. To eliminate driveability issues that may be
caused by these deposits, a supplemental gasoline
additive, such as MOPARInjector Cleanup or
Techron may be used.
Selection Of Engine Oil For Flexible Fuel Vehicles
(E-85) And Gasoline Vehicles
FFV vehicles operated on E-85 require specially formu-
lated engine oils. These special requirements are included
in MOPAR engine oils, and in equivalent oils meeting
Chrysler Specification MS-6395. The manufacturer re-
quires engine oils that are API Certified and meet the
requirements of Material Standard MS-6395. MS-6395
contains additional requirements, developed during ex-
tensive fleet testing, to provide additional protection to Chrysler Group LLC engines. Use MOPAR
or an
equivalent oil meeting the specification MS-6395.
Starting
The characteristics of E-85 fuel make it unsuitable for use
when ambient temperatures fall below 0°F (-18°C). In the
range of 0°F (-18°C) to 32°F (0°C), you may experience an
increase in the time it takes for your engine to start, and
a deterioration in driveability (sags and/or hesitations)
until the engine is fully warmed up.
NOTE: Use of the engine block heater (if equipped) is
beneficial for E-85 startability when the ambient tempera-
ture is less than 32°F (0°C).
516 STARTING AND OPERATING

HAZARD WARNING FLASHERS
The Hazard Warning flasher switch is located on the
switch bank just above the climate controls.Press the switch to turn on the Hazard Warning
flasher. When the switch is activated, all directional
turn signals will flash on and off to warn oncoming
traffic of an emergency. Press the switch a second time to
turn off the Hazard Warning flashers.
This is an emergency warning system and it should not
be used when the vehicle is in motion. Use it when your
vehicle is disabled and it is creating a safety hazard for
other motorists.
When you must leave the vehicle to seek assistance, the
Hazard Warning flashers will continue to operate even
though the ignition is placed in the OFF position.
NOTE: With extended use the Hazard Warning flashers
may wear down your battery.
IF YOUR ENGINE OVERHEATS
In any of the following situations, you can reduce the
potential for overheating by taking the appropriate action.
•On the highways — slow down.
•In city traffic — while stopped, place the transmission
in NEUTRAL, but do not increase the engine idle
speed.
NOTE: There are steps that you can take to slow down
an impending overheat condition:
•If your air conditioner (A/C) is on, turn it off. The A/C
system adds heat to the engine cooling system and
turning the A/C off can help remove this heat.
•You can also turn the temperature control to maximum
heat, the mode control to floor and the blower control
to high. This allows the heater core to act as a
supplement to the radiator and aids in removing heat
from the engine cooling system.
548 WHAT TO DO IN EMERGENCIES

CAUTION!
Driving with a hot cooling system could damage
your vehicle. If the temperature gauge reads HOT
(H), pull over and stop the vehicle. Idle the vehicle
with the air conditioner turned off until the pointer
drops back into the normal range. If the pointer
remains on HOT (H), and you hear continuous
chimes, turn the engine off immediately and call for
service.
WARNING!
You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never try to open a cooling system pressure
cap when the radiator or coolant bottle is hot.
JACKING AND TIRE CHANGING
WARNING!
•Do not attempt to change a tire on the side of the
vehicle close to moving traffic. Pull far enough off
the road to avoid the danger of being hit when
operating the jack or changing the wheel.
•Being under a jacked-up vehicle is dangerous. The
vehicle could slip off the jack and fall on you. You
could be crushed. Never put any part of your body
under a vehicle that is on a jack. If you need to get
under a raised vehicle, take it to a service center
where it can be raised on a lift.
•Never start or run the engine while the vehicle is
on a jack.(Continued)
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