Below is info from pages 341-346 of the Owner's Manual, which covers 4WD and Selec-Terrain:
FOUR WHEEL DRIVE — JEEP ACTIVE DRIVE
(4WD) AND JEEP ACTIVE DRIVE LOW (4WD
LOW)
Your vehicle may be equipped with a Power Transfer
Unit (PTU). This system is automatic with no driver
inputs or additional driving skills required. Under normal
driving conditions, the front wheels provide most of
the traction. If the front wheels begin to lose traction,
power is shifted automatically to the rear wheels. The
greater the front wheel traction loss, the greater the
power transfer to the rear wheels.
Additionally, on dry pavement under heavy throttle
input (where one may have no wheel spin), torque will be
sent to the rear in a preemptive effort to improve vehicle
launch and performance characteristics.
Four Wheel Drive (4x4)
The four wheel drive (4WD) is fully automatic in normal
driving mode.
NOTE: It is not possible to carry out the change of mode
when the car exceeds the speed of 75 mph (120 km/h).
Enabling Four Wheel Drive (4x4)
The buttons for the activation of four wheel drive are
located on the device Selec-Terrain™ and allow you to
select the following:
• 4WD LOCK
• 4WD LOW — (Trailhawk models only)
The Power Transfer Unit (PTU) is locked to ensure
immediate availability of torque to the rear drive axles.
This feature is selectable in AUTO mode and automatic in
the other driving mode. 4WD LOCK can be enabled by
the following ways:
• When the 4WD LOCK button is pressed.
• When the Selec-Terrain™ switch is rotated from AUTO
to any other off-road modes.
Active Drive With Low Control — (Trailhawk models
only)
The 4WD LOW mode helps to improve the off-road
performance in all modes. To enable 4WD Low please
follow the steps below:
Enabling 4WD LOW
With the vehicle stationary, the ignition in the MAR/
RUN or with the engine running, shift the transmission
into DRIVE, REVERSE or NEUTRAL and press the
button once 4WD LOW. The EVIC/DID will display the
message 4WD LOW once the shift is complete.
NOTE: The lights on the Selec-Terrain™ switch may
blink until the shift is complete.
Disabling 4WD LOW
To disable the 4WD LOW mode, the vehicle must be
stationary and the transmission shifted into NEUTRAL.
Press the 4WD LOW button once.
SELEC-TERRAIN™
Selec-Terrain™ combines the capabilities of the vehicle
control systems, along with driver input, to provide the
best performance for all terrains.
Mode Selection Guide
Rotate the Selec-Terrain™ knob to select the desired
mode.
• AUTO: This four-wheel drive operation is a continuous
operation, is fully automatic and can be used on
and off road. This mode balances traction to ensure
maneuverability and acceleration improvement compared
to a car with two wheel drive. This mode also reduces fuel
consumption, since it allows the disconnect of the drive shaft
where conditions permit.
• SNOW: This mode allows you to have greater stability
under conditions of bad weather. For use on and off
road on surfaces with poor traction, such as roads
covered with snow. When in SNOW mode (depending
on certain operating conditions), the transmission may
use second gear (rather than first gear) during
launches, to minimize wheel slippage.
• SAND: For off-road driving or use on surfaces with
poor traction, such as sandy bottoms. The transmission
is set to provide maximum traction.
• MUD: For off-road driving or use on surfaces with
poor traction, such as roads covered by mud or wet
grass.
• ROCK (Trailhawk only): This mode is only available
in 4WD LOW range. The device sets the vehicle to
maximize traction and allow the highest steering capacity
for off-road surfaces. This mode gives you the
maximum performance off-road. Use for low speed
obstacles such as large rocks, deep ruts, etc.
NOTE:
• Rock mode is only available on the vehicles equipped
with the Off-Road package.
• Activate the Hill Descent Control or Selec Speed
Control for steep downhill control. See “Electronic
Brake Control System” in this section for further
information.
