2012 JEEP GRAND CHEROKEE operating temp

DRIVE
This range should be used for most city and highway
driving. It provides the smoothest upshifts and down-
shifts, and the best fuel economy. The transmission
automatically upshifts through underdrive first and sec-
ond gears, direct third gear and overdrive fourth and
fifth gears. The DRIVE position provides optimum driv-
ing characteristics under all normal operating conditions.
To access all six available gears, you must use the
Electronic Range Select (ERS) feature (refer to “Electronic
Range Select (ERS)” in this section).
When frequent transmission shifting occurs (such as
when operating the vehicle under heavy loading condi-
tions, in hilly terrain, traveling into strong head winds, or
while towing heavy trailers), use the Electronic Range
Select (ERS) feature (refer to “Electronic Range Select
(ERS)” in this section) to select a lower gear range. Underthese conditions, using a lower gear range will improve
performance and extend transmission life by reducing
excessive shifting and heat buildup.
If the transmission operating temperature exceeds nor-
mal operating limits, the powertrain controller will
modify the transmission shift schedule and expand the
range of torque converter clutch engagement. This is
done to prevent transmission damage due to overheat-
ing.
If the transmission becomes extremely hot, the “Trans-
mission Temperature Warning Light” may illuminate and
the transmission may downshift out of Overdrive until
the transmission cools down.
NOTE:
Use caution when operating a heavily loaded
vehicle at low speeds (such as towing a trailer up a steep
grade, or in stop-and-go traffic) during hot weather. In
these conditions, torque converter slip can impose a
significant additional heat load on the cooling system.
5
STARTING AND OPERATING 435

Downshifting the transmission to the lowest possible
gear (when climbing a grade), or shifting to NEUTRAL
(when stopped in heavy traffic) can help to reduce this
excess heat generation.
During cold temperatures, transmission operation may
be modified depending on engine and transmission
temperature as well as vehicle speed. This feature im-
proves warm up time of the engine and transmission to
achieve maximum efficiency. Engagement of both the
torque converter clutch and the top overdrive gear are
inhibited until the transmission fluid is warm (refer to the
“Note” under “Torque Converter Clutch” in this section).
During extremely cold temperatures (-16°F [-27°C] or
below), operation may briefly be limited to first and
direct gears only. Normal operation will resume once the
transmission temperature has risen to a suitable level.Transmission Limp Home Mode
Transmission function is monitored electronically for
abnormal conditions. If a condition is detected that could
result in transmission damage, Transmission Limp Home
Mode is activated. In this mode, the transmission remains
in third gear regardless of which forward gear is selected.
PARK, REVERSE, and NEUTRAL will continue to oper-
ate. The Malfunction Indicator Light (MIL) may be illu-
minated. Limp Home Mode allows the vehicle to be
driven to an authorized dealer for service without dam-
aging the transmission.
In the event of a momentary problem, the transmission
can be reset to regain all forward gears by performing the
following steps:
1. Stop the vehicle.
2. Shift the transmission into PARK.
3. Turn the ignition switch to the LOCK/OFF position.
436 STARTING AND OPERATING

gear as the top available gear. Once in ERS mode, tapping
the shift lever to the left (-) or right (+) will change the top
available gear.
To exit ERS mode, simply press and hold the shift lever to
the right (+) until “D” is once again displayed in the shift
lever position indicator in the instrument cluster.
WARNING!
Do not downshift for additional engine braking on a
slippery surface. The drive wheels could lose their
grip and the vehicle could skid, causing an accident
or personal injury.
Screen
Display123456D
Actual Gear(s)
Allowed 1 1-2 1-3 1,2,4 1,2,
4,51,2,
4-6 1-5 NOTE:
To select the proper gear position for maximum
deceleration (engine braking), simply press and hold the
shift lever to the left (-). The transmission will shift to the
range from which the vehicle can best be slowed down.
Overdrive Operation
The automatic transmission includes an electronically
controlled Overdrive (fourth and fifth gears). The trans-
mission will automatically shift into the Overdrive gear if
the following conditions are present:
•the shift lever is in the DRIVE position,
•the transmission fluid has reached an adequate tem-
perature,
•the engine coolant has reached an adequate temperature,
•vehicle speed is sufficiently high,
•the driver is not heavily pressing the accelerator, and
•the TOW/HAUL switch has not been activated.
438 STARTING AND OPERATING

Shifting Procedures
4WDHITo4WDLOW
With the vehicle at speeds of 0 to 3 mph (0 to 5 km/h), the
ignition switch in the ON position or the engine running,
shift the transmission into NEUTRAL, and press the
“4WD LOW” button once on the transfer case switch. The
“4WD LOW” indicator light in the instrument cluster
will begin to flash and remain on solid when the shift is
complete.NOTE:
If shift conditions/interlocks are not met, or a
transfer case motor temperature protection condition ex-
ists, a “For 4x4 Low Slow Below 3 MPH or 5 KPH Put
Trans in N Press 4 Low” message will flash from the
Electronic Vehicle Information Center (EVIC). Refer to
“Electronic Vehicle Information Center (EVIC)” in “Under-
standing Your Instrument Panel” for further information.
Transfer Case Switch
5
STARTING AND OPERATING 443

4WD LOW To 4WD HI
With the vehicle at speeds of 0 to 3 mph (0 to 5 km/h), the
ignition switch in the ON position or the engine running,
shift the transmission into NEUTRAL, and press the
“4WD LOW” button once on the transfer case switch. The
“4WD LOW” indicator light in the instrument cluster
will flash and go out when the shift is complete.
NOTE:
•If shift conditions/interlocks are not met, or a transfer
case motor temperature protection condition exists, a
“For 4x4 High Slow Below 3 MPH or 5 KPH Put Trans
in N Press 4 Low” message will flash from the
Electronic Vehicle Information Center (EVIC). Refer to
“Electronic Vehicle Information Center (EVIC)” in
“Understanding Your Instrument Panel” for further
information.
•Shifting into or out of 4WD LOW is possible with the
vehicle completely stopped; however, difficulty mayoccur due to the mating clutch teeth not being prop-
erly aligned. Several attempts may be required for
clutch teeth alignment and shift completion to occur.
The preferred method is with the vehicle rolling 0 to
3 mph (0 to 5 km/h). If the vehicle is moving faster
than 3 mph (5 km/h), the transfer case will not allow
the shift.
NEUTRAL Shift Procedure
1. Turn the ignition switch to the ON position, engine off.
2. Vehicle stopped, with foot on brake.
3. Place the transmission into NEUTRAL.
4. Hold down the NEUTRAL “pin” switch (with a pen,
etc.) for four seconds until the LED light by the switch
starts to blink indicating shift in progress. The light will
stop blinking (stay on solid) when the NEUTRAL shift is
complete.
444 STARTING AND OPERATING

and/or the flow rate is reduced. If you must cross
flowing water avoid depths in excess of 9 inches (23 cm).
The flowing water can erode the streambed, causing your
vehicle to sink into deeper water. Determine exit point(s)
that are downstream of your entry point to allow for
drifting.
Standing Water
Avoid driving in standing water deeper than 20 inches
(51 cm), and reduce speed appropriately to minimize
wave effects. Maximum speed in 20 inches (51 cm) of
water is less than 5 mph (8 km/h).
Maintenance
After driving through deep water, inspect your vehicle
fluids and lubricants (engine oil, transmission oil, axle,
transfer case) to assure the fluids have not been contami-
nated. Contaminated fluid (milky, foamy in appearance)
should be flushed/changed as soon as possible to pre-
vent component damage.Driving In Snow, Mud And Sand
In heavy snow, when pulling a load, or for additional
control at slower speeds, shift the transmission to a low
gear and shift the transfer case to 4WD LOW if necessary.
Refer to “Four-Wheel Drive Operation” in “Starting and
Operating” for further information. Do not shift to a
lower gear than necessary to maintain forward motion.
Over-revving the engine can spin the wheels and traction
will be lost.
Avoid abrupt downshifts on icy or slippery roads, because
engine braking may cause skidding and loss of control.
Hill Climbing
NOTE:Before attempting to climb a hill, determine the
conditions at the crest and/or on the other side.
Before climbing a steep hill, shift the transmission to a
lower gear and shift the transfer case to 4WD LOW. Use
first gear and 4WD LOW for very steep hills.
456 STARTING AND OPERATING

If you stall or begin to lose forward motionwhile
climbing a steep hill, allow your vehicle to come to a stop
and immediately apply the brakes. Restart the engine,
and shift into REVERSE. Back slowly down the hill,
allowing the compression braking of the engine to help
regulate your speed. If the brakes are required to control
vehicle speed, apply them lightly and avoid locking or
skidding the tires.
WARNING!
If the engine stalls, you lose forward motion, or
cannot make it to the top of a steep hill or grade,
never attempt to turn around. To do so may result in
tipping and rolling the vehicle. Always back care-
fully straight down a hill in REVERSE gear. Never
back down a hill in NEUTRAL using only the brake. Remember, never drive diagonally across a hill always
drive straight up or down.
If the wheels start to slip as you approach the crest of a
hill, ease off the accelerator and maintain forward motion
by turning the front wheels slowly. This may provide a
fresh “bite” into the surface and will usually provide
traction to complete the climb.
Traction Downhill
Shift the transmission into a low gear, and the transfer
case into 4WD LOW range. Let the vehicle go slowly
down the hill with all four wheels turning against engine
compression drag. This will permit you to control the
vehicle speed and direction.
When descending mountains or hills, repeated braking
can cause brake fade with loss of braking control. Avoid
repeated heavy braking by downshifting the transmis-
sion whenever possible.5
STARTING AND OPERATING 457

•If you experience unusual vibration after driving in
mud, slush or similar conditions, check the wheels for
impacted material. Impacted material can cause a
wheel imbalance and freeing the wheels of it will
correct the situation.
POWER STEERING
3.6L Engine
Your vehicle is equipped with an electro-hydraulic power
steering system that will give you good vehicle response
and increased ease of maneuverability in tight spaces.
The system will vary its assist to provide light efforts
while parking and good feel while driving. If the electro-
hydraulic power steering system experiences a fault that
prevents it from providing power steering assist, then the
system will provide mechanical steering capability.
CAUTION!
Extreme steering maneuvers may cause the electri-
cally driven pump to reduce or stop power steering
assistance in order to prevent damage to the system.
Normal operation will resume once the system is
allowed to cool.If the “SERVICE POWER STEERING SYSTEM”
message and a flashing icon are displayed on
the EVIC screen, it indicates that the vehicle
needs to be taken to the dealer for service. It is
likely the vehicle has lost power steering assistance. Refer
to “Electronic Vehicle Information Center (EVIC)” in
“Understanding Your Instrument Panel” for further in-
formation.
If the “POWER STEERING SYSTEM OVER TEMP” mes-
sage and an icon are displayed on the EVIC screen, it
indicates that extreme steering maneuvers may have
5
STARTING AND OPERATING 459