2009 GMC YUKON automatic transmission

Grade Braking (Hydra-Matic®6-Speed
Automatic Transmission)
The Grade Braking shift modes can be activated by
pressing the button on the end of the shift control lever.
While in Range Selection Mode, Grade Braking is
deactivated allowing the driver to select a desired range
of gears.
Grade Braking is only active while the Tow/Haul Mode is
selected and you are not in the Range Selection Mode.
See “Tow/Haul Mode listed previously andAutomatic
Transmission Operation on page 2-29for more
information on the Range Selection Mode. Grade Braking
assists in maintaining desired vehicle speeds when
driving on downhill grades by automatically implementing
a shift schedule that utilizes the engine and transmission
to slow the vehicle. This reduces wear on the braking
system and increases control of the vehicle. Grade
Braking monitors vehicle speed, acceleration, engine
torque and brake pedal usage. Using this information, it
detects when the truck is on a downhill grade and the
driver desires to slow the vehicle by pressing the brake.
Also seeTowing a Trailer on page 4-52for more
information.
Cruise Grade Braking (Hydra-Matic®
6-Speed Automatic Transmission)
Cruise Grade Braking assists when driving on a downhill
grade. It maintains vehicle speed by automatically
implementing a shift schedule that uses the engine
and the transmission to slow the vehicle. Cruise Grade
Braking operates while Cruise Control is engaged in
Tow/Haul mode to assist in maintaining vehicle speed
under loaded vehicle conditions. It utilizes vehicle
acceleration and deviation from desired speed to
determine the correct gear for the operating condition.
If vehicle speed is above the desired speed the
transmission will downshift to slow the vehicle. If vehicle
speed is near or below desired speed the trans will
upshift, allowing vehicle speed to increase.
While in the Range Select Mode (RSM) mode, Cruise
Grade Braking is not available.
SeeAutomatic Transmission Operation on page 2-29.
2-36

2m(Two-Wheel Drive High):This setting is used for
driving in most street and highway situations. The
front axle is not engaged in two-wheel drive. This setting
also provides the best fuel economy.
AUTO (Automatic Four-Wheel Drive):This setting is
ideal for use when road surface traction conditions are
variable. When driving your vehicle in AUTO, the front
axle is engaged, but the vehicle’s power is primarily sent
to the rear wheels. When the vehicle’s software
determines a need for more traction, the system will
transfer more power to the front wheels. Driving in this
mode results in slightly lower fuel economy than
Two-Wheel Drive High.
4
m(Four-Wheel Drive High):Use the four-wheel high
position when you need extra traction, such as on snowy
or icy roads or in most off-road situations. This setting
also engages your front axle to help drive the vehicle.
This is the best setting to use when plowing snow.
4
n(Four-Wheel Drive Low):This setting also engages
the front axle and delivers extra torque. You may never
need this setting. It sends maximum power to all four
wheels. You might choose Four-Wheel Drive Low if you
are driving off-road in deep sand, deep mud, deep snow,
and while climbing or descending steep hills.
The vehicle has StabiliTrak
®. Shifting into
Four-Wheel-Drive Low will turn Traction Control and
StabiliTrak
®off. SeeStabiliTrak®System on page 4-6.
{CAUTION:
Shifting the transfer case to N (Neutral) can cause
the vehicle to roll even if the transmission is in
P (Park). You or someone else could be seriously
injured. Be sure to set the parking brake before
placing the transfer case in N (Neutral). See
Parking Brake on page 2-42.
N (Neutral):Shift the vehicle’s transfer case to
N (Neutral) only when towing the vehicle. See
Recreational Vehicle Towing on page 4-44orTowing
Your Vehicle on page 4-44for more information.
If the SERVICE 4 WHEEL DRIVE message stays on,
you should take the vehicle to your dealer/retailer
for service. See “SERVICE 4 WHEEL DRIVE message”
underDIC Warnings and Messages on page 3-64.
2-38

Shifting Into Four-Wheel Drive High or
AUTO (Automatic Four-Wheel Drive)
Turn the knob to the Four-Wheel High or AUTO position.
This can be done at any speed, except when shifting
from Four-Wheel Drive Low. The indicator light will ash
while shifting. It will remain on when the shift is
completed.
Shifting Into Two-Wheel Drive High
Turn the knob to the Two-Wheel High position. This
can be done at any speed, except when shifting
from Four-Wheel Drive Low.
See shifting out of Four-Wheel Drive Low later in this
section for more information.
Shifting Into Four-Wheel Drive Low
When Four-Wheel Low is engaged, vehicle speed
should be kept below 45 mph (72 km/h). Extended
high-speed operation in 4L may damage or shorten
the life of the drivetrain.
To shift to the Four-Wheel Drive Low position, the ignition
must be in ON/RUN and the vehicle must be stopped or
moving less than 3 mph (5 km/h) with the transmissionin N (Neutral). The preferred method for shifting into
Four-Wheel Drive Low is to have the vehicle moving
1 to 2 mph (1.6 to 3.2 km/h). Turn the knob to the
Four-Wheel Drive Low position. You must wait for the
Four-Wheel Drive Low indicator light to stop ashing and
remain on before shifting the transmission into gear.
Notice:Shifting the transmission into gear before
the Four-Wheel Drive Low indicator light has
stopped ashing could damage the transfer case.
To help avoid damaging the vehicle, always wait for
the Four-Wheel Drive Low indicator light to stop
ashing before shifting the transmission into gear.
The vehicle may have signicant engagement noise
and bump when shifting between Four-Wheel Drive Low
and Four-Wheel Drive High ranges or from N (Neutral)
while the engine is running.
If the knob is turned to the Four-Wheel Drive Low
position when the vehicle is in gear and/or moving, the
Four-Wheel Drive Low indicator light will ash for
30 seconds and not complete the shift unless the vehicle
is moving less than 3 mph (5 km/h) and the transmission
is in N (Neutral). After 30 seconds the transfer case
will shift to Four-Wheel Drive High mode.
2-39

{CAUTION:
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 rmly 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).
{CAUTION:
Four-wheel drive vehicles with the transfer case
in N (Neutral) will allow the vehicle to roll, even
if the automatic transmission shift lever is in
P (Park). So, be sure the transfer case is in a
drive gear — not in N (Neutral). Always set the
parking brake.Follow the proper steps to be sure the vehicle will not
move. SeeShifting Into Park on page 2-44.
If pulling a trailer, seeTowing a Trailer on page 4-52.
Mirrors
Manual Rearview Mirror
Hold the inside rearview mirror in the center to move it
for a clearer view behind your vehicle. Adjust the
mirror to avoid glare from the headlamps behind you.
Push the tab forward for daytime use and pull it for
nighttime use.
Automatic Dimming Rearview Mirror
The vehicle may have an automatic dimming rearview
mirror.
Vehicles with OnStar
®have three additional control
buttons for the OnStar®system. See your dealer/retailer
for more information about OnStar®and how to
subscribe to it. SeeOnStar®System on page 2-64for
more information about the services OnStar®provides.
2-48

The main components of the instrument panel are the following:
A.Outlet Adjustment on page 3-31.
B.Turn Signal/Multifunction Lever on page 3-7.
C.Instrument Panel Cluster on page 3-35.
D.Hazard Warning Flashers on page 3-6.
E. Shift Lever. SeeAutomatic Transmission Operation
on page 2-29.
F.Tow/Haul Mode on page 2-35(If Equipped).
G.Driver Information Center (DIC) on page 3-51.
H.Audio System(s) on page 3-83.
I.Exterior Lamps on page 3-14.
J.Dome Lamp Override on page 3-19.Instrument
Panel Brightness on page 3-18.Fog Lamps
on page 3-17(If Equipped).
K.Hood Release on page 5-12.
L. Integrated Trailer Brake Controller (If Equipped).
Towing a Trailer on page 4-52.
M. Automatic Transfer Case Control. (If Equipped).
SeeFour-Wheel Drive on page 2-37.N.Cruise Control on page 3-12.
O.Tilt Wheel on page 3-6.
P.Horn on page 3-6.
Q.Audio Steering Wheel Controls on page 3-136.
R.Climate Control System on page 3-22orDual
Automatic Climate Control System on page 3-25
(If Equipped).
S.Accessory Power Outlet(s) on page 3-20. Cigarette
Lighter (If Equipped). SeeAshtray(s) and Cigarette
Lighter on page 3-21.
T.StabiliTrak
®System on page 4-6(If Equipped).
Pedal Adjust Button (If Equipped). SeeAdjustable
Throttle and Brake Pedal on page 2-27.Ultrasonic
Rear Parking Assist (URPA) on page 2-53(If
Equipped). Heated Windshield Washer Fluid Button
(If Equipped). SeeWindshield Washer on
page 3-10.Power Assist Steps on page 2-17
(If Equipped).
U.Glove Box on page 2-74.
3-5

Headlamps on Reminder
A reminder chime will sound when the headlamps or
parking lamps are manually turned on and the ignition is
off and a door is open. To disable the chime, turn the
light off.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier for
others to see the front of your vehicle during the day.
Fully functional daytime running lamps are required on all
vehicles rst sold in Canada.
The DRL system will come on when the following
conditions are met:
The ignition is on.
The exterior lamps control is in AUTO.
The transmission is not in P (Park).
The light sensor determines it is daytime.
When the DRL are on, only the DRL lamps will be on.
The taillamps, sidemarker, instrument panel lights,
and other lamps will not be on.
When it begins to get dark, the automatic headlamp
system will switch from DRL to the headlamps.To turn off the DRL lamps, turn the exterior lamps control
to the OFF position and then release. For vehicles rst
sold in Canada, the transmission must be in the P (Park)
position, before the DRL lamps can be turned off.
Automatic Headlamp System
When it is dark enough outside, the automatic headlamp
system turns on the headlamps at the normal brightness,
along with the taillamps, sidemarker, parking lamps,
and the instrument panel lights. The radio lights will also
be dim.
To turn off the automatic headlamp system, turn the
exterior lamps switch to the off position and then release
it. For vehicles rst sold in Canada, the transmission
must be in the P (Park) position, before the automatic
headlamp system can be turned off.
The vehicle has a light sensor located on the top of the
instrument panel in the defroster grille that regulates
when the automatic headlamps turn on. Do not cover the
sensor or the headlamps will come on whenever the
ignition is on.
The system may also turn on the headlamps when
driving through a parking garage, heavy overcast
weather, or a tunnel. This is normal.
3-16

Transmission Temperature
Press the trip/fuel button until TRANS TEMP displays.
This display shows the temperature of the automatic
transmission uid in either degrees Fahrenheit (°F) or
degrees Celsius (°C).
Blank Display
This display shows no information.
Vehicle Information Menu Items
T
(Vehicle Information):Press this button to scroll
through the following menu items:
Oil Life
Press the vehicle information button until OIL LIFE
REMAINING displays. This display shows an estimate of
the oil’s remaining useful life. If you see 99% OIL LIFE
REMAINING on the display, that means 99% of the
current oil life remains. The engine oil life system will alert
you to change the oil on a schedule consistent with your
driving conditions.
When the remaining oil life is low, the CHANGE ENGINE
OIL SOON message will appear on the display. See
“CHANGE ENGINE OIL SOON” underDIC Warnings
and Messages on page 3-64. You should change the
oil as soon as you can. SeeEngine Oil on page 5-15.In addition to the engine oil life system monitoring the oil
life, additional maintenance is recommended in the
Maintenance Schedule in this manual. SeeScheduled
Maintenance on page 6-4for more information.
Remember, you must reset the OIL LIFE display
yourself after each oil change. It will not reset itself.
Also, be careful not to reset the OIL LIFE display
accidentally at any time other than when the oil has just
been changed. It cannot be reset accurately until the
next oil change. To reset the engine oil life system, see
Engine Oil Life System on page 5-18.
Side Blind Zone Alert
If your vehicle has the Side Blind Zone Alert (SBZA)
system, this display allows the system to be turned on or
off. Once in this display, press the set/reset button to
select between ON or OFF. If you choose ON, the
system will be turned on. If you choose OFF, the system
will be turned off. When the SBZA system is turned
off, the DIC will display the SIDE BLIND ZONE ALERT
SYSTEM OFF message as a reminder that the
system has been turned off. SeeDIC Warnings and
Messages on page 3-64andSide Blind Zone Alert
(SBZA) on page 2-56for more information.
3-55

Transmission Temperature
Press the trip odometer reset stem until TRANS
TEMP displays. This display shows the temperature
of the automatic transmission uid in either degrees
Fahrenheit (°F) or degrees Celsius (°C).
Trailer Gain and Output
On vehicles with the Integrated Trailer Brake Control
(ITBC) system, the trailer brake display appears in the
DIC. Press the trip odometer reset stem until TRAILER
GAIN and OUTPUT display.
TRAILER GAIN shows the trailer gain setting. This
setting can be adjusted from 0.0 to 10.0 with either a
trailer connected or disconnected. To adjust this setting,
see “Integrated Trailer Brake Control System” under
Towing a Trailer on page 4-52for more information.OUTPUT shows the power output to the trailer anytime
a trailer with electric brakes is connected. Output is
displayed in 0 to 10 bars. Dashes may appear in
the OUTPUT display. See “Integrated Trailer Brake
Control System” underTowing a Trailer on page 4-52
for more information.
Compass Zone Setting
This display allows for setting the compass zone. See
DIC Compass on page 3-61for more information.
Compass Recalibration
This display allows for calibrating the compass. SeeDIC
Compass on page 3-61for more information.
3-59