wheel torque JEEP GRAND CHEROKEE 2012 WK2 / 4.G Owners Manual

The light also will turn on when the parking brake is
applied with the ignition switch in the ON/RUN posi-
tion.
NOTE:This light shows only that the parking brake is
applied. It does not show the degree of brake application.
15. Anti-Lock Brake (ABS) Light This light monitors the Anti-Lock Brake System
(ABS). The light will turn on when the ignition
switch is turned to the ON/RUN position and
may stay on for as long as four seconds.
If the ABS light remains on or turns 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 system will continue to operate
normally if the BRAKE warning light is not on. If the ABS light is on, the brake system should be serviced
as soon as possible to restore the benefits of Anti-Lock
brakes. If the ABS light does not turn on when the
ignition switch is turned to the ON/RUN position, have
the light inspected by an authorized dealer.
16. 4 LOW
This light alerts the driver that the vehicle is in
the four-wheel drive LOW mode. The front and
rear driveshafts are mechanically locked to-
gether forcing the front and rear wheels to
rotate at the same speed. Low range provides a greater
gear reduction ratio to provide increased torque at the
wheels.
For further information on four-wheel drive operation
and proper use, refer to “Four-Wheel Drive Operation —
If Equipped” in “Starting And Operating”.
17. Speedometer
Indicates vehicle speed.
292 UNDERSTANDING YOUR INSTRUMENT PANEL

required. You may experience reduced performance, an
elevated/rough idle or engine stall and your vehicle may
require towing.
•Engine Temperature Warning LightThis light warns of an overheated engine condi-
tion. As temperatures rise and the gauge ap-
proaches H,this indicator will illuminate and a
single chime will sound after reaching a set threshold.
Further overheating will cause the temperature gauge to
pass H,the indicator will continuously flash and a
continuous chime will occur until the engine is allowed
to cool.
If the light turns on while driving, safely pull over and
stop the vehicle. If the A/C system is on, turn it off. Also,
shift the transmission into NEUTRAL and idle the ve-
hicle. If the temperature reading does not return to
normal, turn the engine off immediately and call for service. Refer to “If Your Engine Overheats” in “What To
Do In Emergencies” for more information.
•Transmission Temperature Warning Light
This light indicates that there is excessive trans-
mission fluid temperature that might occur
with severe usage such as trailer towing. It may
also occur when operating the vehicle in a high
torque converter slip condition, such as 4-wheel-drive
operation (e.g., snow plowing, off- road operation). If this
light comes on, stop the vehicle and run the engine at idle
or faster, with the transmission in NEUTRAL until the
light goes off.
CAUTION!
Continuous driving with the Transmission Tempera-
ture Warning Light illuminated will eventually cause
severe transmission damage or transmission failure.
4
UNDERSTANDING YOUR INSTRUMENT PANEL 309

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.
5
STARTING AND OPERATING 441

5. Repeat Steps 1 to 4 to shift out of NEUTRAL.
NOTE:If shift conditions/interlocks are not met, a “To
Tow Vehicle Safely, Read Neutral Shift Procedure in
Owners Manual” 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.
Quadra-Drive
II System – If Equipped
The optional Quadra-Drive II System features two
torque transfer couplings. The couplings include an
Electronic Limited-Slip Differential (ELSD) rear axle and
the Quadra-Trac II transfer case. The optional ELSD axle
is fully automatic and requires no driver input to operate.
Under normal driving conditions, the unit functions as a
standard axle, balancing torque evenly between left and
right wheels. With a traction difference between left and
right wheels, the coupling will sense a speed difference.
As one wheel begins to spin faster than the other, torque
will automatically transfer from the wheel that has less
traction, to the wheel that has traction. While the transfer
case and axle coupling differ in design, their operation is
similar. Follow the Quadra-Trac II transfer case shifting
information, preceding this section, for shifting this
system.
Neutral Switch
5
STARTING AND OPERATING 445

After Driving Off-Road
Off-road operation puts more stress on your vehicle than
does most on-road driving. After going off-road, it is
always a good idea to check for damage. That way you
can get any problems taken care of right away and have
your vehicle ready when you need it.
•Completely inspect the underbody of your vehicle.
Check tires, body structure, steering, suspension, and
exhaust system for damage.
•Inspect the radiator for mud and debris and clean as
required.
•Check threaded fasteners for looseness, particularly on
the chassis, drivetrain components, steering, and sus-
pension. Retighten them, if required, and torque to the
values specified in the Service Manual.
•Check for accumulations of plants or brush. These
things could be a fire hazard. They might hide damage
to fuel lines, brake hoses, axle pinion seals, and
propeller shafts.
•After extended operation in mud, sand, water, or
similar dirty conditions, have the radiator, fan, brake
rotors, wheels, brake linings, and axle yokes inspected
and cleaned as soon as possible.
WARNING!
Abrasive material in any part of the brakes may cause
excessive wear or unpredictable braking. You might
not have full braking power when you need it to
prevent a collision. If you have been operating your
vehicle in dirty conditions, get your brakes checked
and cleaned as necessary.
458 STARTING AND OPERATING

WARNING!
The ABS cannot prevent the natural laws of physics
from acting on the vehicle, nor can it increase the
traction afforded by prevailing road conditions. The
ABS cannot prevent collisions, including those re-
sulting from excessive speed in turns, driving on
very slippery surfaces, or hydroplaning. The capa-
bilities 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.
Traction Control System (TCS)
This system monitors the amount of wheel spin of each of
the driven wheels. If wheel spin is detected, brake
pressure is applied to the slipping wheel(s) and engine
power is reduced to provide enhanced acceleration and
stability. A feature of the TCS system, Brake LimitedDifferential (BLD), functions similar to a limited-slip
differential and controls the wheel spin across a driven
axle. If one wheel on a driven axle is spinning faster than
the other, the system will apply the brake of the spinning
wheel. This will allow more engine torque to be applied
to the wheel that is not spinning. This feature remains
active even if ESC system is in the “Partial Off” mode.
Refer to “Electronic Stability Control (ESC)” in this
section for further information.
Brake Assist System (BAS)
The BAS is designed to optimize the vehicle’s braking
capability during emergency braking maneuvers. The
system detects an emergency braking situation by sens-
ing 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
5
STARTING AND OPERATING 465

WARNING!
To avoid the risk of forcing the vehicle off the jack,
do not tighten the wheel nuts fully until the vehicle
has been lowered. Failure to follow this warning may
result in personal injury.9. Lower the vehicle by turning the jack screw counter-
clockwise, and remove the jack and wheel blocks.
10. Finish tightening the lug nuts. Push down on the
wrench while at the end of the handle for increased
leverage. Tighten the lug nuts in a star pattern until each
nut has been tightened twice. The correct wheel nut
tightness is 110 ft lbs (150 N·m). If in doubt about the
correct tightness, have them checked with a torque
wrench by your authorized dealer or at a service station.
11. Lower the jack to the fully closed position and return
it and the tools to the proper positions in the foam tray.
Mounting Spare Tire6
WHAT TO DO IN EMERGENCIES 557

12. Remove the small center cap and securely store the
road wheel in the cargo area.
13. Have the aluminum road wheel and tire repaired as
soon as possible, properly secure the spare tire with the
special wing nut torqued to 3.7 ft-lbs (5 N·m), reinstall the
jack and tool kit foam tray, and latch the rear load floor
cover.WARNING!
A loose tire or jack, thrown forward in a collision or
hard stop could endanger the occupants of the ve-
hicle. Always stow the jack parts and the spare tire in
the places provided. Have the deflated (flat) tire
repaired or replaced immediately.
Road Tire Installation
1. Mount the road tire on the axle.
2. Install the remaining lug nuts with the cone shaped
end of the nut toward the wheel. Lightly tighten the lug
nuts.
Stowed Spare
558 WHAT TO DO IN EMERGENCIES

WARNING!
To avoid the risk of forcing the vehicle off the jack,
do not tighten the wheel nuts fully until the vehicle
has been lowered. Failure to follow this warning may
result in personal injury.
3. Lower the vehicle to the ground by turning the jack
handle counterclockwise.
4. Finish tightening the lug nuts. Push down on the
wrench while at the end of the handle for increased
leverage. Tighten the lug nuts in a star pattern until each
nut has been tightened twice. The correct tightness of
each lug nut is 110 ft/lbs (150 N·m). If in doubt about the
correct tightness, have them checked with a torque
wrench by your authorized dealer or service station. 5. After 25 miles (40 km) check the lug nut torque with a
torque wrench to ensure that all lug nuts are properly
seated against the wheel.
JUMP-STARTING
If your vehicle has a discharged battery it can be jump-
started using a set of jumper cables and a battery in
another vehicle or by using a portable battery booster
pack. Jump-starting can be dangerous if done improperly
so please follow the procedures in this section carefully.
NOTE:
When using a portable battery booster pack
follow the manufacturer’s operating instructions and
precautions.
6
WHAT TO DO IN EMERGENCIES 559