Page 417 of 675

conditions may be reduced. In all cases, 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 fourth gear (for 66RFE transmission) or third gear (for
AS66RC transmission) regardless of which forward gear
is selected. If an AS66RC equipped truck enters Limp
Home Mode at highway speeds, it will initially engage
fifth gear, until the vehicle slows to a speed where third
gear can be engaged. PARK, REVERSE, and NEUTRAL
will continue to operate. The Malfunction Indicator Light
(MIL) may be illuminated. Limp Home Mode allows the
vehicle to be driven to an authorized dealer for service
without damaging 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 OFF position.
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. 5STARTING AND OPERATING 415
Page 418 of 675

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
transmission is in DRIVE. For example, if you set the
transmission gear limit to 4 (fourth gear), the transmis-
sion will not shift above fourth gear, but will shift
through the lower gears normally.
You can switch between DRIVE and ERS mode at any
vehicle speed. When the gear selector is in the DRIVE
position, the transmission will operate automatically,
shifting between all available gears. Tapping the ERS (-)
switch will activate ERS mode, display the current gear in
the instrument cluster, and set that gear as the top
available gear. Once in ERS mode, tapping (-) or (+) will
change the top available gear. To exit ERS mode, simply push and hold the ERS (+)
switch until the gear limit display disappears from the
instrument cluster. Column Gear Selector416 STARTING AND OPERATING
Page 431 of 675

3. When the shift is complete, the indicator light for the
selected position will stop flashing and remain ON.
If One Or More Shift Conditions Are Not Met:
1. The indicator light for the current position will remain
ON.
2. The newly selected position indicator light will con-
tinue to flash.
3. The transfer case will not shift.
NOTE: Before retrying a selection, make certain that all
the necessary requirements for selecting a new transfer
case position have been met. To retry the selection, turn
the control knob back to the current position, wait five
seconds, and retry selection. To find the shift require-
ments, refer to the Shifting Procedure for your transfer
case, located in this section. The “SVC 4WD Warning Light” monitors the electronic
shift four-wheel drive system. If this light remains on
after engine start up or illuminates during driving, it
means that the four-wheel drive system is not function-
ing properly and that service is required.
WARNING!Always engage the parking brake when powering
down the vehicle if the “SVC 4WD Warning Light” is
illuminated. Not engaging the parking brake may
allow the vehicle to roll, which may cause personal
injury.
NOTE: Do not attempt to make a shift while only the
front or rear wheels are spinning, as this can cause
damage to driveline components. 5STARTING AND OPERATING 429
Page 440 of 675

If for some reason the power assist is interrupted, it will
still be possible to steer your vehicle. Under these condi-
tions, you will observe a substantial increase in steering
effort, especially at very low vehicle speeds and during
parking maneuvers.
NOTE:
• Increased noise levels at the end of the steering wheel
travel are considered normal and do not indicate that
there is a problem with the power steering system.
• Upon initial start-up in cold weather, the power steer-
ing pump may make noise for a short amount of time.
This is due to the cold, thick fluid in the steering
system. This noise should be considered normal, and it
does not in any way damage the steering system. CAUTION!Prolonged operation of the steering system at the end
of the steering wheel travel will increase the steering
fluid temperature and it should be avoided when
possible. Damage to the power steering pump may
occur.
Power Steering Fluid Check
Checking the power steering fluid level at a defined
service interval is not required. The fluid should only be
checked if a leak is suspected, abnormal noises are
apparent, and/or the system is not functioning as antici-
pated. Coordinate inspection efforts through an autho-
rized dealer.438 STARTING AND OPERATING
Page 443 of 675

The parking brake should always be applied whenever
the driver is not in the vehicle.
WARNING!• 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 gear selector.
• Do not leave the Key Fob in or near the vehicle, or
in a location accessible to children, and do not
leave the ignition of a vehicle equipped with
Keyless Enter-N-Go in the ACC or ON/RUN mode.
A child could operate power windows, other con-
trols, or move the vehicle. (Continued) WARNING! (Continued)• Be sure the parking brake is fully disengaged
before driving; failure to do so can lead to brake
failure and a collision.
• Always fully apply the parking brake when leav-
ing your vehicle or it may roll and cause damage or
injury. Also, be certain to leave an automatic trans-
mission in PARK, a manual transmission in RE-
VERSE or first gear. Failure to do so may cause the
vehicle to roll and cause damage or injury.
CAUTION!If the “Brake Warning Light” remains on with the
parking brake released, a brake system malfunction
is indicated. Have the brake system serviced by an
authorized dealer immediately. 5STARTING AND OPERATING 441
Page 445 of 675

Assist (HSA), Traction Control System (TCS), Electronic
Stability Control (ESC), and Electronic Roll Mitigation
(ERM). These systems work together to enhance both
vehicle stability and control in various driving condi-
tions.
Your vehicle may also be equipped with Trailer Sway
Control (TSC) and Hill Descent Control (HDC).
Electronic Brake Force Distribution (EBD)
This function manages the distribution of the braking
torque between the front and rear axles by limiting
braking pressure to the rear axle. This is done to prevent
overslip of the rear wheels to avoid vehicle instability,
and to prevent the rear axle from entering ABS before the
front axle. Brake System Warning Light
The red “Brake System Warning Light” will turn on when
the ignition switch is turned to the ON position and may
stay on for as long as four seconds.
If the “Brake System Warning Light” remains on or
comes on while driving, it indicates that the brake system
is not functioning properly and that immediate service is
required. If the “Brake System Warning Light” does not
come on when the ignition switch is turned to the ON
position, have the light repaired as soon as possible.
Anti-Lock Brake System (ABS)
The Anti-Lock Brake System (ABS) provides increased
vehicle stability and brake performance under most
braking conditions. The system automatically prevents
wheel lock, and enhances vehicle control during braking. 5STARTING AND OPERATING 443
Page 447 of 675

WARNING! (Continued)braking or steering efficiency beyond that afforded
by the condition of the vehicle brakes and tires or
the traction afforded.
• The ABS cannot prevent collisions, including those
resulting from excessive speed in turns, following
another vehicle too closely, or hydroplaning.
• The capabilities of an ABS equipped vehicle must
never be exploited in a reckless or dangerous
manner that could jeopardize the user ’s safety or
the safety of others.
ABS is designed to function with the OEM tires. Modifi-
cation may result in degraded ABS performance.
Anti-Lock Brake Warning Light
The amber “Anti-Lock Brake Warning Light” will turn on
when the ignition switch is turned to the ON position
and may stay on for as long as four seconds. If the “Anti-Lock Brake Warning Light” remains on or
comes 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
System Warning Light” is not on.
If the “Anti-Lock Brake Warning Light” is on, the brake
system should be serviced as soon as possible to restore
the benefits of anti-lock brakes. If the “Anti-Lock Brake
Warning Light” does not come on when the ignition
switch is turned to the ON position, have the light
repaired as soon as possible.
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 5STARTING AND OPERATING 445
Page 461 of 675
• The cluster icon and switch lamp will flash for several
seconds then extinguish when the driver pushes the
HDC switch but enable conditions are not met.
• The cluster icon and switch lamp will flash for several
seconds then extinguish when HDC disables due to
excess speed.
• The cluster icon and switch lamp will flash when HDC
deactivates due to overheated brakes. The flashing will
stop and HDC will activate again once the brakes have
cooled sufficiently.
WARNING!HDC is only intended to assist the driver in control-
ling vehicle speed when descending hills. The driver
must remain attentive to the driving conditions and
is responsible for maintaining a safe vehicle speed. TIRE SAFETY INFORMATION
Tire Markings
1 — U.S. DOT Safety Standards
Code (TIN) 4 — Maximum Load
2 — Size Designation 5 — Maximum Pressure
3 — Service Description 6 — Treadwear, Traction and
Temperature Grades 5STARTING AND OPERATING 459