2007 GMC YUKON XL DENALI trailer

Starting and Operating Your
Vehicle
New Vehicle Break-In
Notice:Your vehicle does not need an
elaborate break-in. But it will perform better in
the long run if you follow these guidelines:
Keep your speed at 55 mph (88 km/h)
or less for the rst 500 miles (805 km).
Do not drive at any one constant speed,
fast or slow, for the rst 500 miles
(805 km). Do not make full-throttle starts.
Avoid downshifting to brake, or slow,
the vehicle.
Avoid making hard stops for the rst
200 miles (322 km) or so. During this
time your new brake linings are not yet
broken in. Hard stops with new linings
can mean premature wear and earlier
replacement. Follow this breaking-in
guideline every time you get new brake
linings.
Do not tow a trailer during break-in. See
Towing a Trailer on page 400for the
trailer towing capabilities of your vehicle
and more information.
Following break-in, engine speed and load can
be gradually increased.
139

PARK (P):This position locks your rear wheels. It
is the best position to use when you start your
engine because your 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 Park.
See Torque Lock (Automatic Transmission) under
Shifting Into Park (P) on page 153for more
information.
{CAUTION:
It is dangerous to get out of your vehicle
if the shift lever is not fully in PARK (P)
with the parking brake rmly set. Your
vehicle can roll.
Do not leave your 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 your vehicle will not
move, even when you are on fairly level
ground, always set your parking brake
and move the shift lever to PARK (P). See
Shifting Into Park (P) on page 153.Ifyou
are pulling a trailer, seeTowing a Trailer
on page 400.
146

DRIVE (D):This position is for normal driving. It
provides the best fuel economy for your vehicle.
If you need more power for passing, and you are:
Going less than about 35 mph (55 km/h), push
your accelerator pedal about halfway down.
Going about 35 mph (55 km/h) or more, push
the accelerator all the way down.
Drive (D) 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
underLoss of Control on page 357.
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.MANUAL MODE (M):This position lets drivers
select the range of gears appropriate for current
driving conditions. If your vehicle has this feature,
see “Driver Shift Control” later in this section.
Notice:Spinning the tires or holding the
vehicle in one place on a hill using only
the accelerator pedal may damage the
transmission. If you are stuck, do not spin
the tires. When stopping on a hill, use
the brakes to hold the vehicle in place.
Your vehicle has a shift stabilization feature that
adjusts the transmission shifting to the current
driving conditions in order to reduce rapid upshifts
and downshifts. This shift stabilization feature is
designed to determine, before making an upshift,
if the engine will be able to maintain vehicle
speed by analyzing things such as throttle position,
vehicle load, and hill grade. If the shift stabilization
feature determines that a current vehicle speed
cannot be maintained, the transmission does
not upshift and instead holds the current gear.
In some cases, this may appear to be a delayed
shift, however the transmission is operating
normally.
148

When in the MANUAL MODE (M) a number will
display next to the M, indicating the current gear
that has been selected. The number displayed in
the gear indicator is the highest gear that can be
used. However, your vehicle can automatically shift
to lower gears as it adjusts to driving conditions.
This means that all gears below that number are
available. When FIFTH (5) is selected, FIRST (1)
through FIFTH (5) gears are automatically shifted
by the vehicle, but SIXTH (6) cannot be used until
the plus/minus button located on the steering
column lever is used to change to the gear.
The DSC controls the vehicle and engine speed
while driving down a hill or towing a trailer, by
allowing you to select a desired range of gears.
The transmission will prevent a gear range until a
speed that is appropriate for current driving
conditions is achieved. If shifting is prevented for
any reason, the currently selected gear will
ash multiple times in the instrument panel cluster.
Grade Braking is not available when the Driver
Shift Control is active. SeeTow/Haul Mode
on page 150for more information.
While using the DSC, Cruise Control and the
Tow/Haul mode can be used.Tow/Haul Mode
Your vehicle has a tow/haul mode. The tow/haul
mode adjusts the transmission shift pattern to
reduce shift cycling, providing increased
performance, vehicle control, and transmission
cooling when towing or hauling heavy loads.
150

Press the button located on the end of the shift
lever to turn the tow/haul on or off. When the
tow/haul is on, a light on the instrument panel
cluster will come on.
SeeTow/Haul Mode Light on page 242for more
information.
Also see “Tow Haul Mode” underTowing a Trailer
on page 400for more information.
The tow/haul mode works with the Autoride
®
feature, if the vehicle has this, to enhance the ride
when trailering or with a loaded vehicle. See
Autoride
®on page 399.
Grade Braking
Grade Braking assists when driving on a downhill
grade. It maintains the vehicle’s speed by
automatically implementing a shift schedule that
uses the engine and the transmission to slow
the vehicle. This reduces wear on the brakes
system and increases control of the vehicle. The
system constantly monitors the vehicle’s speed,
acceleration, throttle position, and whether
the brake pedal is being pressed, and determines
when to keep the current vehicle speed or to
slow down. The system will then automatically
command downshifts that reduces the vehicles
speed, until the brake pedal is no longer
being pressed. This indicates the desired vehicle
speed has been reached.
The tow/haul mode and grade braking shift
modes can be activated by pressing the button on
the end of the shift control stalk. While in the
DSC mode, grade braking is deactivated, allowing
the driver to select a gear.
SeeAutomatic Transmission Operation on
page 145for more information.
151

Parking Brake
To set the parking brake, hold the regular brake
pedal down with your right foot. Push down
the parking brake pedal with your left foot.
A chime will activate and the warning light will
ash when the parking brake is applied and
the vehicle is moving at least 3 mph (5 km/h) for
at least three seconds.
To release the parking brake, hold the regular
brake pedal down.Pull the bottom edge of the lever, located above
the parking brake pedal, with the parking
brake symbol, to release the parking brake.
If the ignition is on when the parking brake is
released, the brake system warning light will go off.
Notice:Driving with the parking brake on
can overheat the brake system and cause
premature wear or damage to brake system
parts. Verify that the parking brake is fully
released and the brake warning light is
off before driving.
If you are towing a trailer and are parking on any
hill, seeTowing a Trailer on page 400.
152

Shifting Into Park (P)
{CAUTION:
It can be dangerous to get out of your
vehicle if the shift lever is not fully in
PARK (P) with the parking brake rmly
set. Your vehicle can roll. If you have left
the engine running, the vehicle can move
suddenly. You or others could be injured.
To be sure your 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 400.
1. Hold the brake pedal down with your right
foot and set the parking brake.
2. Move the shift lever into the PARK (P)
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.
4. Remove the key and take it with you. If you
can leave your vehicle with the ignition key in
your hand, your vehicle is in PARK (P).
Leaving Your Vehicle With the
Engine Running
{CAUTION:
It can be dangerous to leave your vehicle
with the engine running. Your vehicle
could move suddenly if the shift lever is
not fully in PARK (P) with the parking
brake rmly set. And, if you leave the
vehicle with the engine running, it could
overheat and even catch re. You or
others could be injured. Do not leave your
vehicle with the engine running.
If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P)
and the parking brake is rmly set before
you leave it. After you move the shift lever into
PARK (P), hold the regular brake pedal down.
Then, see if you can move the shift lever away
from PARK (P) without rst pulling it toward you.
If you can, it means that the shift lever was
not fully locked into PARK (P).
153

Running the Engine While Parked
It is better not to park with the engine running.
But if you ever have to, here are some things
to know.
{CAUTION:
Idling the engine with the climate control
system off could allow dangerous exhaust
into your vehicle. See the earlier caution
underEngine Exhaust on page 156.
Also, idling in a closed-in place can let
deadly carbon monoxide (CO) into your
vehicle even if the climate control fan is at
the highest setting. One place this can
happen is a garage. Exhaust — with
CO — can come in easily. NEVER park in
a garage with the engine running.
Another closed-in place can be a blizzard.
SeeWinter Driving on page 386.
{CAUTION:
It can be dangerous to get out of your
vehicle if the shift lever is not fully in
PARK (P) with the parking brake rmly
set. Your vehicle can roll. Do not leave
your 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 your vehicle will not move,
even when you are on fairly level ground,
always set your parking brake and move
the shift lever to PARK (P).
Follow the proper steps to be sure your vehicle
will not move. SeeShifting Into Park (P) on
page 153.
If you are pulling a trailer, seeTowing a Trailer on
page 400.
157