engine GMC YUKON 2007 User Guide

Ignition Positions
Use the key to turn the ignition switch to
four different positions.
A (LOCK):This position locks the ignition and
transmission. It is a theft-deterrent feature. You will
only be able to remove the key when the ignition
is turned to LOCK.Notice:Using a tool to force the key from
the ignition switch could cause damage
or break the key. Use the correct key and turn
the key only with your hand. Make sure the
key is all the way in. If it is, turn the steering
wheel left and right while you turn the key
hard. If none of this works, then your vehicle
needs service.
B (ACCESSORY):This position lets you use
things like the radio and the windshield wipers
when the engine is off.
Notice:Lengthy operation of features such as
the radio in the accessory ignition position
and the RUN position may drain the battery and
prevent your vehicle from starting. Do not
operate your vehicle in the accessory ignition
position for a long period of time.
C (RUN):This is the position for driving. It is the
position the switch returns to after the engine
starts, and you release the key.
D (START):This position starts the engine.
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Key In the Ignition
Never leave your vehicle with the keys inside, as it
is an easy target for joy riders or thieves. If you
leave the key in the ignition and park your vehicle,a
chime will sound, when you open the driver’s door.
Always remember to remove your key from the
ignition and take it with you. This will lock your
ignition and transaxle. Also, always remember to
lock the doors.
Retained Accessory Power (RAP)
Your vehicle has a Retained Accessory Power
(RAP) feature which will allow certain features on
your vehicle to continue to work up to 10 minutes
after the ignition key is turned to LOCK.
The radio, power windows, and if the vehicle has
a sunroof and the OnStar
®System, will work
when the ignition key is in RUN or ACCESSORY.
Once the key is turned from RUN to LOCK,
these features will continue to work for up to
10 minutes or until a door is opened.
Starting the Engine
Move your shift lever to PARK (P) or
NEUTRAL (N). Your engine will not start in any
other position — that is a safety feature. To
restart when you are already moving, use
NEUTRAL (N) only.
Notice:Do not try to shift to PARK (P) if your
vehicle is moving. If you do, you could
damage the transmission. Shift to PARK (P)
only when your vehicle is stopped.
1. With your foot off the accelerator pedal, turn
the ignition key to START. When the engine
starts, let go of the key. The idle speed will go
down as your engine gets warm. Do not
race the engine immediately after starting it.
Operate the engine and transmission
gently until the oil warms up and lubricates all
moving parts.
Your vehicle has a Computer-Controlled
Cranking System. This feature assists in
starting the engine and protects the electrical
system.
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If the ignition key is turned to the START, and
then released when the engine begins cranking,
the engine will continue cranking until the
vehicle starts or until it exceeds the maximum
cranking time allowed, approximately
15 seconds to prevent cranking motor damage.
To prevent gear damage, this system also
prevents cranking if the engine is already
running. The engine cranking can be stopped
by turning the ignition switch to the
ACCESSORY or LOCK.
Notice:Cranking the engine for long periods
of time, by returning the key to the START
position immediately after cranking has ended,
can overheat and damage the cranking
motor and drain the battery. Waiting about
15 seconds between each try, to allow
the cranking motor to cool down, will prevent
damage due to overheating.
2. If the engine does not start within 10 seconds,
push the accelerator pedal all the way to the
oor, while you hold the ignition key in
START. When the engine starts, let go of the
key and let up on the accelerator pedal.
Wait about 15 seconds between each try.When starting your engine in very cold weather
(below 0°F or−18°C), do this:
1. With your foot off the accelerator pedal, turn
the ignition key to START and hold it there up
to 15 seconds. When the engine starts, let
go of the key.
2. If your engine still will not start, or starts but
then stops, it could be ooded with too much
gasoline. Try pushing your accelerator
pedal all the way to the oor and holding it
there as you hold the key in START for about
three seconds. When the engine starts, let
go of the key and accelerator. If the vehicle
starts briey but then stops again, do the
same thing, but this time keep the pedal down
for ve or six seconds. This clears the extra
gasoline from the engine.
Notice:Your engine is designed to work with
the electronics in your vehicle. If you add
electrical parts or accessories, you could
change the way the engine operates. Before
adding electrical equipment, check with
your dealer. If you do not, your engine might
not perform properly. Any resulting damage
would not be covered by your vehicle’s
warranty.
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Engine Coolant Heater
Your vehicle may have an engine coolant heater.
In very cold weather, 0°F (−18°C) or colder,
the engine coolant heater can help. You will get
easier starting and better fuel economy during
engine warm-up.
Usually, the coolant heater should be plugged
in a minimum of four hours prior to starting your
vehicle. At temperatures above 32°F (0°C), use of
the coolant heater is not required. Your vehicle
may also have an internal thermostat in the
plug end of the cord. This will prevent operation of
the engine coolant heater when the temperature
is at or above 0°F (−18°C) as noted on the cord.
To Use the Engine Coolant Heater
1. Turn off the engine.
2. Open the hood and unwrap the electrical
cord. The cord is located on the driver’s
side of the engine compartment, near
the power steering uid reservoir.
3. Plug the cord into a normal, grounded
110-volt AC outlet.
{CAUTION:
Plugging the cord into an ungrounded
outlet could cause an electrical shock.
Also, the wrong kind of extension cord
could overheat and cause a re. You
could be seriously injured. Plug the cord
into a properly grounded three-prong
110-volt AC outlet. If the cord will not
reach, use a heavy-duty three-prong
extension cord rated for at least 15 amps.
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4. Before starting the engine, be sure to unplug
and store the cord as it was before to keep it
away from moving engine parts. If you do
not, it could be damaged.
How long should you keep the coolant heater
plugged in? The answer depends on the outside
temperature, the kind of oil you have, and
some other things. Instead of trying to list
everything here, we ask that you contact your
dealer in the area where you will be parking your
vehicle. The dealer can give you the best
advice for that particular area.Automatic Transmission Operation
Your vehicle has an 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 PARK (P).
There are several different positions for the
shift lever.
See “Driver Shift Control (DSC)” later in this
section.
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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.
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REVERSE (R):Use this gear to back up.
Notice:Shifting to REVERSE (R) while your
vehicle is moving forward could damage
the transmission. The repairs would not
be covered by your warranty. Shift to
REVERSE (R) only after your vehicle is
stopped.
To rock your vehicle back and forth to get out
of snow, ice, or sand without damaging your
transmission, seeIf Your Vehicle is Stuck in Sand,
Mud, Ice, or Snow on page 390.
NEUTRAL (N):In this position, your engine does
not connect with the wheels. To restart when
you are already moving, use NEUTRAL (N) only.
Also, use NEUTRAL (N) when your vehicle is
being towed.
{CAUTION:
Shifting into a drive gear while your
engine is running at high speed is
dangerous. Unless your foot is rmly on
the brake pedal, your vehicle could move
very rapidly. You could lose control and
hit people or objects. Do not shift into a
drive gear while your engine is running at
high speed.
Notice:Shifting out of PARK (P) or
NEUTRAL (N) with the engine running at high
speed may damage the transmission. The
repairs would not be covered by your warranty.
Be sure the engine is not running at high
speed when shifting your vehicle.
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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.
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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.
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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.
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