engine JEEP GRAND CHEROKEE 2012 WK2 / 4.G Repair Manual

PARK
This range supplements the parking brake by locking the
transmission. The engine can be started in this range.
Never attempt to use PARK while vehicle is in motion.
Apply the parking brake when leaving vehicle in this
range.
When parking on a level surface, you may place the shift
lever in the PARK position first, and then apply the
parking brake.
When parking on a hill, apply the parking brake before
placing the shift lever in PARK, otherwise the load on the
transmission locking mechanism may make it difficult to
move the shift lever out of PARK. As an added precau-
tion, turn the front wheels toward the curb on a downhill
grade and away from the curb on an uphill grade.WARNING!
•Never use the PARK position as a substitute for
the parking brake. Always apply the parking
brake fully when parked to guard against vehicle
movement and possible injury or damage.
•Your vehicle could move and injure you and others
if it is not completely in PARK. Check by trying to
move the shift lever rearward (with the brake
pedal released), after you have placed it in PARK.
Make sure the transmission is in PARK before
leaving the vehicle.(Continued)
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WARNING! (Continued)
•It is dangerous to move the shift lever out of PARK
or NEUTRAL if the engine speed is higher than
idle speed. If your foot is not firmly pressing the
brake pedal, the vehicle could accelerate quickly
forward or in reverse. You could lose control of the
vehicle and hit someone or something. Only shift
into gear when the engine is idling normally and
when your foot is firmly pressing the brake pedal.(Continued)
WARNING! (Continued)
•Unintended movement of a vehicle could injure
those in or near the vehicle. As with all vehicles,
you should never exit a vehicle while the engine is
running. Before exiting a vehicle, always apply the
parking brake, shift the transmission into PARK,
and remove the key fob. Once the key fob is
removed, the shift lever is locked in the PARK
position, securing the vehicle against unwanted
movement.
•When leaving the vehicle, always remove the key
fob from the ignition and lock your vehicle.(Continued)
432 STARTING AND OPERATING

WARNING! (Continued)
•Never leave children alone in a vehicle, or with
access to an unlocked vehicle. Allowing children
to be in a vehicle unattended is dangerous for a
number of reasons. A child or others could be
seriously or fatally injured. Children should be
warned not to touch the parking brake, brake
pedal or the shift lever. Do not leave the key fob in
or near the vehicle, and do not leave Keyless
Enter-N-Go in the ACC or ON/RUN mode. A child
could operate power windows, other controls, or
move the vehicle.
CAUTION!
•Before moving the shift lever out of PARK, you
must turn the ignition switch from the LOCK/OFF
position to the ON/RUN position, and also press
the brake pedal. Otherwise, damage to the shift
lever could result.
•DO NOT race the engine when shifting from
PARK or NEUTRAL into another gear range, as
this can damage the drivetrain.
The following indicators should be used to ensure that
you have engaged the shift lever into the PARK position:
•When shifting into PARK, move the shift lever all the
way forward and to the left until it stops and is fully
seated.
•Look at the shift lever position display and verify that
it indicates the PARK position.
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•With brake pedal released, verify that the shift lever
will not move out of PARK.
REVERSE
This range is for moving the vehicle backward. Shift into
REVERSE only after the vehicle has come to a complete
stop.
NEUTRAL
Use this range when the vehicle is standing for prolonged
periods with engine running. The engine may be started
in this range. Set the parking brake and shift the trans-
mission into PARK if you must leave the vehicle.
WARNING!
Do not coast in NEUTRAL and never turn off the
ignition to coast down a hill. These are unsafe
practices that limit your response to changing traffic
or road conditions. You might lose control of the
vehicle and have a collision.
CAUTION!
Towing the vehicle, coasting, or driving for any other
reason with the transmission in NEUTRAL can result
in severe transmission damage. Refer to “Recre-
ational Towing” in “Starting And Operating” and
“Towing A Disabled Vehicle” in “What To Do In
Emergencies” for further information.
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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

4. Wait approximately 10 seconds.
5. Restart the engine.
6. Shift into the desired gear range. If the problem is no
longer detected, the transmission will return to normal
operation.
NOTE:Even if the transmission can be reset, we recom-
mend that you visit your authorized dealer at your
earliest possible convenience. Your authorized dealer has
diagnostic equipment to determine if the problem could
recur.
If the transmission cannot be reset, authorized dealer
service is required.
Electronic Range Select (ERS) Operation
The Electronic Range Select (ERS) shift control allows the
driver to limit the highest available gear when the shift
lever is in the DRIVE position. For example, if you shift the transmission into 3 (third gear), the transmission will
never shift above third gear, but will shift down into
second and first gear normally.
Use of ERS (or TOW/HAUL mode) also enables an
additional underdrive gear which is not normally used
during through-gear accelerations. This additional gear
can improve vehicle performance and cooling capability
when towing a trailer on certain grades. In ERS mode,
gears 1 though 3 are underdrive gears, and ERS 4 is direct
drive. ERS 5 and 6 (Overdrive gears ) are the same as the
normal fourth and fifth gears.
You can switch between DRIVE and ERS mode at any
vehicle speed. When the shift lever is in the DRIVE
position, the transmission will operate automatically,
shifting between all available gears. Tapping the shift
lever to the left (-) will activate ERS mode, display the
current gear in the instrument cluster, and maintain that
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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

When To Use TOW/HAUL Mode
When driving in hilly areas, towing a trailer, carrying a
heavy load, etc., and frequent transmission shifting oc-
curs, press the TOW/HAUL switch to select TOW/
HAUL mode. This will improve performance and reduce
the potential for transmission overheating or failure due
to excessive shifting. When operating in TOW/HAUL
mode, transmission upshifts are delayed, and the trans-
mission will automatically downshift (for engine brak-
ing) during steady braking maneuvers.The “TOW/HAUL Indicator Light” will illuminate in the
instrument cluster to indicate that TOW/HAUL mode
has been activated. Pressing the switch a second time
restores normal operation. If the TOW/HAUL mode is
desired, the switch must be pressed each time the engine
is started.
TOW/HAUL Switch
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Torque Converter Clutch
A feature designed to improve fuel economy has been
included in the automatic transmission on your vehicle.
A clutch within the torque converter engages automati-
cally at calibrated speeds. This may result in a slightly
different feeling or response during normal operation in
the upper gears. When the vehicle speed drops or during
some accelerations, the clutch automatically disengages.
NOTE:
•The torque converter clutch will not engage, and the
transmission will not shift into the top overdrive gear,
until the transmission fluid and engine coolant are
warm [usually after 1 to 3 miles (1.6 to 4.8 km) of
driving]. Because top gear is disabled, and engine
speed is higher when the torque converter clutch is not
engaged, it may seem as if the transmission is not
shifting properly when cold. This is normal. Using theElectronic Range Select (ERS) feature, when the trans-
mission is sufficiently warm, will demonstrate that the
transmission is able to shift into and out of Overdrive.
•If the vehicle has not been driven for several days, the
first few seconds of operation after shifting the trans-
mission into gear may seem sluggish. This is due to the
fluid partially draining from the torque converter into
the transmission. This condition is normal and will not
cause damage to the transmission. The torque con-
verter will refill within five seconds after starting the
engine.
FOUR-WHEEL DRIVE OPERATION
Quadra-Trac I
Operating Instructions/
Precautions – If Equipped
The Quadra-Trac I is a single-speed (HI range only)
transfer case, which provides convenient full-time four-
wheel drive. No driver interaction is required. The Brake
Traction Control (BTC) System, which combines standard
440 STARTING AND OPERATING

ABS and Traction Control, provides resistance to any
wheel that is slipping to allow additional torque transfer
to wheels with traction.
NOTE:The Quadra-Trac I system is not appropriate
for conditions where 4WD LOW range is recommended.
Refer to “Off-Road Driving Tips” in “Starting and Oper-
ating” for further information.
Quadra-Trac II Operating Instructions/
Precautions – If Equipped
The Quadra-Trac II transfer case is fully automatic in the
normal driving 4WD AUTO mode. The Quadra-Trac II 
transfer case provides three mode positions:
•4WD HI
•NEUTRAL
•4WD LOW
This transfer case is fully automatic in the 4WD HI mode. When additional traction is required, the 4WD LOW
position can be used to lock the front and rear driveshafts
together and force the front and rear wheels to rotate at
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.
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