warning GMC SIERRA DENALI 2010 Workshop Manual

Automatic Transmission Operation
The vehicle has a Hydra-Matic®6L80 automatic
transmission, and has an electronic shift position
indicator within the instrument panel cluster. The
electronic shift position indicator displays when the shift
lever is moved out of P (Park).
There are several different positions for the shift lever.
Light Duty 6‐Speed Automatic Transmission Shown (Heavy Duty 6‐Speed Similar)
See “Range Selection Mode” later in this section.
P (Park) : This position locks your rear wheels. It is the
best position to use when you start the engine because
the vehicle cannot move easily.
When parked on a hill, especially when the vehicle has
a heavy load, you may notice an increase in the effort to
shift out of P (Park). See Torque Lock (Automatic
Transmission) under Shifting Into Park
on page 3‑35for more information.
{WARNING:
It is dangerous to get out of the vehicle if the shift
lever is not fully in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure the
vehicle will not move, even when you are on fairly
level ground, always set the parking brake and
move the shift lever to P (Park). See Shifting Into
Park
on page 3‑35. If you are pulling a trailer,
see Towing a Trailer on page 5‑42.
R (Reverse) : Use this gear to back up.
Notice: Shifting to R (Reverse) while the vehicle is
moving forward could damage the transmission.
The repairs would not be covered by the vehicle
warranty. Shift to R (Reverse) only after the vehicle
is stopped.
To rock the vehicle back and forth to get out of snow,
ice, or sand without damaging the transmission, see If
Your Vehicle is Stuck in Sand, Mud, Ice, or Snow
on
page 5‑29.
3-28

N (Neutral) :In this position, the engine does not
connect with the wheels. To restart the engine when the
vehicle is already moving, use N (Neutral) only. Also,
use N (Neutral) when the vehicle is being towed.
{WARNING:
Shifting into a drive gear while the engine is
running at high speed is dangerous. Unless your
foot is firmly on the brake pedal, the vehicle could
move very rapidly. You could lose control and hit
people or objects. Do not shift into a drive gear
while the engine is running at high speed.
Notice: Shifting out of P (Park) or N (Neutral) with
the engine running at high speed may damage the
transmission. The repairs would not be covered by
the vehicle warranty. Be sure the engine is not
running at high speed when shifting the vehicle. D (Drive) :
This position is for normal driving. It provides
the best fuel economy for the vehicle. If you need more
power for passing, and you are:
.Going less than about 35 mph (55 km/h), push the
accelerator pedal about halfway down.
.Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
D (Drive) can be used when towing a trailer, carrying a
heavy load, driving on steep hills, or for off-road driving.
You may want to shift the transmission to a lower gear
selection if the transmission shifts too often.
Downshifting the transmission in slippery road
conditions could result in skidding, see “Skidding”under
Loss of Control on page 5‑11.
When temperatures are very cold, the Hydra-Matic
®
Automatic Transmission's gear shifting may be delayed
providing more stable shifts until the engine warms up.
Shifts may be more noticeable with a cold transmission.
This difference in shifting is normal.
3-29

Parking Brake
Set the parking brake by holding the regular brake
pedal down, then pushing down the parking brake
pedal.If the ignition is on, the brake system warning light will
come on. See
Brake System Warning Light
on
page 4‑34.
Notice: Driving with the parking brake on can
overheat the brake system and cause premature
wear or damage to brake system parts. Make sure
that the parking brake is fully released and the
brake warning light is off before driving.
To release the parking brake, hold the regular brake
pedal down, then push down momentarily on the
parking brake pedal until you feel the pedal release.
Slowly pull your foot up off the park brake pedal. If the
parking brake is not released when you begin to drive,
the brake system warning light will flash and a chime
will sound warning you that the parking brake is still on.
If you are towing a trailer and are parking on a hill, see
Towing a Trailer on page 5‑42.
3-34

Shifting Into Park
{WARNING:
It can be dangerous to get out of the vehicle if the
shift lever is not fully in P (Park) with the parking
brake firmly set. The vehicle can roll. If you have
left the engine running, the vehicle can move
suddenly. You or others could be injured. To be
sure the vehicle will not move, even when you are
on fairly level ground, use the steps that follow.
If you are pulling a trailer, seeTowing a Trailer
on
page 5‑42
.
1. Hold the brake pedal down, then set the parking brake.
2. Move the shift lever into the P (Park) position by pulling the shift lever toward you and moving it up
as far as it will go.
3. Turn the ignition key to LOCK/OFF.
4. Remove the key and take it with you. If you can leave the vehicle with the ignition key in your hand,
the vehicle is in P (Park).
Leaving the Vehicle With the Engine
Running
{WARNING:
It can be dangerous to leave the vehicle with the
engine running. The vehicle could move suddenly
if the shift lever is not fully in P (Park) with the
parking brake firmly set. And, if you leave the
vehicle with the engine running, it could overheat
and even catch fire. You or others could be
injured. Do not leave the vehicle with the engine
running.
If you have to leave the vehicle with the engine running,
be sure the vehicle is in P (Park) and the parking brake
is firmly set. After the shift lever is moved into P (Park),
hold the regular brake pedal down. Then, see if you can
move the shift lever away from P (Park) without first
pulling it toward you. If you can, it means that the shift
lever was not fully locked into P (Park).
3-35

Parking Over Things That Burn
{WARNING:
Things that can burn could touch hot exhaust
parts under the vehicle and ignite. Do not park
over papers, leaves, dry grass, or other things that
can burn.
Engine Exhaust
{WARNING:
Engine exhaust contains Carbon Monoxide (CO)
which cannot be seen or smelled. Exposure to CO
can cause unconsciousness and even death.
Exhaust may enter the vehicle if:
.The vehicle idles in areas with poor ventilation
(parking garages, tunnels, deep snow that
may block underbody airflow or tail pipes).(Continued)
WARNING: (Continued)
.The exhaust smells or sounds strange or
different.
.The exhaust system leaks due to corrosion or
damage.
.The vehicle’s exhaust system has been
modified, damaged or improperly repaired.
.There are holes or openings in the vehicle
body from damage or after-market
modifications that are not completely sealed.
If unusual fumes are detected or if it is suspected
that exhaust is coming into the vehicle:
.Drive it only with the windows
completely down.
.Have the vehicle repaired immediately.
Never park the vehicle with the engine running in
an enclosed area such as a garage or a building
that has no fresh air ventilation.
3-37

Running the Vehicle While Parked
It is better not to park with the engine running. But if you
ever have to, here are some things to know.
{WARNING:
Idling a vehicle in an enclosed area with poor
ventilation is dangerous. Engine exhaust may
enter the vehicle. Engine exhaust contains
Carbon Monoxide (CO) which cannot be seen or
smelled. It can cause unconsciousness and even
death. Never run the engine in an enclosed area
that has no fresh air ventilation. For more
information, seeEngine Exhaust on page 3‑37.
{WARNING:
It can be dangerous to get out of the vehicle if the
automatic transmission shift lever is not fully in
P (Park) with the parking brake firmly set. The
vehicle can roll. Do not leave the vehicle when the
engine is running unless you have to. If you have
left the engine running, the vehicle can move
suddenly. You or others could be injured. To be
sure the vehicle will not move, even when you are
on fairly level ground, always set the parking
brake and move the shift lever to P (Park).
Follow the proper steps to be sure the vehicle will not
move. See Shifting Into Park on page 3‑35.
If parking on a hill and pulling a trailer, see Towing a
Trailer on page 5‑42.
3-38

Outside Convex Mirror
{WARNING:
A convex mirror can make things, like other
vehicles, look farther away than they really are.
If you cut too sharply into the right lane, you could
hit a vehicle on the right. Check the inside mirror
or glance over your shoulder before changing
lanes.
The passenger side mirror is convex shaped. A convex
mirror's surface is curved so more can be seen from the
driver seat.
Outside Heated Mirrors
For vehicles with heated mirrors:
<(Rear Window Defogger): Press to heat the
mirrors. If the vehicle has a towing mirror, only the
upper glass of the mirror is heated. The lower convex
part of the towing mirror is not heated.
Depending on the vehicle's features, see “Rear Window
Defogger” under,Climate Control System (With Air
Conditioning)
on page 4‑17or Climate Control System
(With Heater Only)on page 4‑20or Dual Automatic
Climate Control Systemon page 4‑21for more
information.
3-42

Object Detection Systems
Ultrasonic Rear Parking
Assist (URPA)
For vehicles with the Ultrasonic Rear Parking Assist
(URPA) system, it operates at speeds less than
8 km/h (5 mph), and assists the driver with parking and
avoiding objects while in R (Reverse). The sensors on
the rear bumper are used to detect the distance to an
object up to 2.5 m (8 ft) behind the vehicle, and at least
25.4 cm (10 in) off the ground.
{WARNING:
The Ultrasonic Rear Parking Assist (URPA)
system does not replace driver vision. It cannot
detect:
.Objects that are below the bumper,
underneath the vehicle, or if they are too close
or far from the vehicle
.Children, pedestrians, bicyclists, or pets.(Continued)
WARNING: (Continued)
If you do not use proper care before and while
backing; vehicle damage, injury, or death could
occur. Even with URPA, always check behind the
vehicle before backing up. While backing, be sure
to look for objects and check the vehicle's mirrors.
How the System Works
URPA comes on automatically when the shift lever is
moved into R (Reverse). A single tone sounds to
indicate the system is working.
URPA operates only at speeds less than
5 mph (8 km/h).
An obstacle is indicated by audible beeps. The interval
between the beeps becomes shorter as the vehicle gets
closer to the obstacle. When the distance is less than
30 cm (12 in) the beeps are continuous.
To be detected, objects must be at least 25.4 cm (10 in)
off the ground and below tailgate level. Objects must
also be within 2.5 m (8 ft) from the rear bumper. This
distance may be less during warmer or humid weather.
3-43

The system can be
disabled by pressing the
rear park aid disable
button located next to the
radio.
The indicator light will come on and PARK ASSIST OFF
displays on the Driver Information Center (DIC) to
indicate that URPA is off, see DIC Warnings and
Messages on page 4‑57.
Notice: If you use URPA while the tailgate is
lowered, it may not detect an object behind your
vehicle, and you might back into the object and
damage your vehicle. Always verify the tailgate is
closed when using URPA or turn off URPA when
driving with the tailgate lowered.
When the System Does Not Seem to
Work Properly
If the URPA system will not activate due to a temporary
condition, the messages PARK ASSIST OFF or PARK
ASST BLOCKED SEE OWNERS MANUAL will be
displayed on the DIC.
SERVICE PARK ASSIST : If this message occurs, take
the vehicle to your dealer/retailer to repair the system. PARK ASSIST OFF :
This message occurs if the driver
disables the system.
PARK ASST BLOCKED SEE OWNERS MANUAL :
This message can occur under the following conditions:
.The ultrasonic sensors are not clean. Keep the
vehicle's rear bumper free of mud, dirt, snow, ice
and slush. For cleaning instructions, see Washing
Your Vehicle on page 6‑108.
.The park assist sensors are covered by frost or
ice. Frost or ice can form around and behind the
sensors and may not always be seen; this can
occur after washing the vehicle in cold weather.
The message may not clear until the frost or ice
has melted.
.A trailer was attached to the vehicle, or a bicycle or
an object was hanging out of the tailgate during the
last drive cycle. Once the attached object is
removed and the tailgate is raised, URPA will
return to normal operation.
.A tow bar is attached to the vehicle.
.The vehicle's bumper is damaged. Take the vehicle
to your dealer/retailer to repair the system.
.Other conditions may affect system performance,
such as vibrations from a jackhammer or the
compression of air brakes on a very large truck.
3-44

If the system is still disabled, after driving forward at
least 40 km/h (25 mph), take the vehicle to your dealer/
retailer.
Rear Vision Camera (RVC)
This vehicle may have a Rear Vision Camera system.
Read this entire section before using it.
{WARNING:
The Rear Vision Camera (RVC) system does not
replace driver vision. RVC does not:
.Detect objects that are outside the camera's
field of view, below the bumper, or underneath
the vehicle.
.Detect children, pedestrians, bicyclists,
or pets.
Do not back the vehicle by only looking at the
RVC screen, or use the screen during longer,
higher speed backing maneuvers or where there
could be cross-traffic. Your judged distances using
the screen will differ from actual distances. (Continued)
WARNING: (Continued)
So if you do not use proper care before backing
up, you could hit a vehicle, child, pedestrian,
bicyclist, or pet, resulting in vehicle damage,
injury, or death. Even though the vehicle has the
RVC system, always check carefully before
backing up by checking behind and around the
vehicle.
Vehicles Without Navigation System
The rear vision camera system is designed to help the
driver when backing up by displaying a view of the area
behind the vehicle. When the key is in the ON/RUN
position and the driver shifts the vehicle into
R (Reverse), the video image automatically appears on
the inside rear view mirror. Once the driver shifts out of
R (Reverse), the video image automatically disappears
from the inside rear view mirror.
Turning the Rear Vision Camera System
Off or On
To turn off the rear vision camera system, press and
hold
z, located on the inside rearview mirror, until the
left indicator light turns off. The rear camera vision
display is now disabled.
3-45