2012 GMC YUKON change time

Black plate (82,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-82 Driving and Operating
.Pressing a Trailer Gain
button–If the Trailer Brake
Display Page is not currently
displayed, pressing a Trailer
Gain button will first recall the
current Trailer Gain setting. After
the Trailer Brake Display Page is
displayed, each press and
release of the gain buttons will
then cause the Trailer Gain
setting to change.
.Activating the Manual Trailer
Brake Apply lever
.Connecting a trailer equipped
with electric trailer brakes
All DIC warning and service
messages must first be
acknowledged by the driver by
pressing the odometer trip stem or
the DIC Vehicle Information button
(if equipped) before the Trailer
Brake Display Page can be
displayed and Trailer Gain can be
adjusted. TRAILER GAIN
–This setting is
displayed anytime the Trailer Brake
Display Page is active. This setting
can be adjusted from 0.0 to 10.0
with either a trailer connected or
disconnected. To adjust the Trailer
Gain, press one of the Trailer Gain
adjustment buttons located on the
Trailer Brake Control Panel. Press
and hold a gain button to cause the
Trailer Gain to continuously adjust.
To turn the output to the trailer off,
adjust the Trailer Gain setting to
0.0 (zero).
0.0 (zero) gain is the factory default
setting. To properly adjust trailer
gain, see the Trailer Gain
Adjustment Procedure later in this
section.
TRAILER OUTPUT –This is
displayed any time a trailer with
electric brakes is connected. Output
to the electric brakes is based on
the amount of vehicle braking
present and relative to the Trailer
Gain setting. Output is displayed
from 0 to 10 bars for each gain
setting. The Trailer Output will indicate
“- - -
- - -“ on the Trailer Brake Display
Page whenever the following occur:
.No trailer is connected.
.A trailer without electric brakes
is connected (no DIC message
is displayed).
.A trailer with electric brakes has
become disconnected (a
CHECK TRAILER WIRING
message will also be displayed
on the DIC).
.There is a fault present in the
wiring to the electric trailer
brakes (a CHECK TRAILER
WIRING message will also be
displayed on the DIC).
.There is a fault in the ITBC
system (a SERVICE TRAILER
BRAKE SYSTEM message will
also be displayed in the DIC).

Black plate (83,1)GMC Yukon/Yukon XL Owner Manual - 2012
Driving and Operating 9-83
Manual Trailer Brake Apply
The Manual Trailer Brake Apply
Lever is located on the Trailer Brake
Control Panel and is used to apply
the trailer’s electric brakes
independent of the vehicle’s brakes.
This lever is used in the Trailer Gain
Adjustment Procedure to properly
adjust the power output to the trailer
brakes. Sliding the lever to the left
will apply only the trailer brakes.
The power output to the trailer is
indicated in the Trailer Brake
Display Page in the DIC. If the
vehicle’s service brakes are applied
while using the Manual Trailer Brake
Apply Lever, the trailer output power
will be the greater of the two.
The trailer and the vehicle's brake
lamps will come on when either
vehicle braking or manual trailer
brakes are applied. Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and must
be adjusted any time vehicle
loading, trailer loading or road
surface conditions change.
Setting the Trailer Gain properly is
needed for the best trailer stopping
performance. A trailer that is
over-gained may result in locked
trailer brakes. A trailer that is
under-gained may result in not
enough trailer braking. Both of these
conditions may result in poorer
stopping and stability of the vehicle
and trailer.
Use the following procedure to
correctly adjust Trailer Gain for each
towing condition:
1. Make sure the trailer brakes are
in proper working condition.
2. Connect a properly loaded trailer to the vehicle and make all
necessary mechanical and
electrical connections. See
Vehicle Load Limits on
page 9‑16 for more information.
3. After the electrical connection is made to a trailer equipped with
electric brakes:
.A TRAILER CONNECTED
message will be briefly
displayed on the DIC
display.
.The Trailer Brake Display
Page will appear on the
DIC showing TRAILER
GAIN and TRAILER
OUTPUT.

Black plate (84,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-84 Driving and Operating
.In the Trailer Output display
on the DIC,“- - - - - -“will
disappear if there is no
error present. Connecting a
trailer without electric
brakes will not clear the six
dashed lines.
4. Adjust the Trailer Gain by using the gain adjustment (+ / -)
buttons on the Trailer Brake
Control Panel.
5. Drive the vehicle with the trailer attached on a level road surface
representative of the towing
condition and free of traffic at
about 32 to 40 km/h (20 to
25 mph) and fully apply the
Manual Trailer Brake Apply
lever.
Adjusting trailer gain at speeds
lower than 32 to 40 km/h (20 to
25 mph) may result in an
incorrect gain setting. 6. Adjust the Trailer Gain to just
below the point of trailer wheel
lock-up, indicated by trailer
wheel squeal or tire smoke when
a trailer wheel locks.
Trailer wheel lock-up may not
occur if towing a heavily loaded
trailer. In this case, adjust the
Trailer Gain to the highest
allowable setting for the towing
condition.
7. Re-adjust Trailer Gain any time vehicle loading, trailer loading or
road surface conditions change
or if trailer wheel lock-up is
noticed at any time while towing
Other ITBC Related DIC Messages
In addition to displaying TRAILER
GAIN and TRAILER OUTPUT
through the DIC, trailer connection
and ITBC system status is displayed
in the DIC.
TRAILER CONNECTED –This
message will be briefly displayed
when a trailer with electric brakes is
first connected to the vehicle. This message will automatically turn off
in about ten seconds. The driver
can also acknowledge this message
before it automatically turns off.
CHECK TRAILER WIRING
–This
message will be displayed if:
1. The ITBC system first
determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected from the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically turn
off in about thirty seconds. This
message will also turn off if the
driver acknowledges this
message off or if the trailer
harness is re-connected.
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This
message will also turn off if the
driver acknowledges this
message off or if the trailer
harness is re-connected.

Black plate (8,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-8 Vehicle Care
Engine Oil
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
.Always use engine oil approved
to the proper specification and of
the proper viscosity grade. See
“Selecting the Right Engine Oil”
in this section.
.Check the engine oil level
regularly and maintain the
proper oil level. See“Checking
Engine Oil” and“When to Add
Engine Oil” in this section.
.Change the engine oil at the
appropriate time. See Engine Oil
Life System on page 10‑10.
.Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.
Checking Engine Oil
It is a good idea to check the engine
oil level at each fuel fill. In order to
get an accurate reading, the vehicle
must be on level ground. The
engine oil dipstick handle is a yellow
loop. See Engine Compartment
Overview on page 10‑6 for the
location of the engine oil dipstick.
Obtaining an accurate oil level
reading is essential:
1. If the engine has been running recently, turn off the engine and
allow several minutes for the oil
to drain back into the oil pan.
Checking the oil level too soon
after engine shutoff will not
provide an accurate oil level
reading.
2. Pull out the dipstick and clean it with a paper towel or cloth,
then push it back in all the way.
Remove it again, keeping the tip
down, and check the level.
When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick, add
1 L (1 qt) of the recommended oil
and then recheck the level. See
“Selecting the Right Engine Oil” in
this section for an explanation of
what kind of oil to use. For engine
oil crankcase capacity, see
Capacities and Specifications on
page 12‑2.
Notice: Do not add too much
oil. Oil levels above or below
the acceptable operating range
shown on the dipstick are harmful
to the engine. If you find that
you have an oil level above the
operating range, i.e., the engine

Black plate (10,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-10 Vehicle Care
Engine Oil Additives/Engine
Oil Flushes
Do not add anything to the oil. The
recommended oils with the dexos
specification and displaying the
dexos certification mark are all that
is needed for good performance and
engine protection.
Engine oil system flushes are not
recommended and could cause
engine damage not covered by the
vehicle warranty.
What to Do with Used Oil
Used engine oil contains certain
elements that can be unhealthy for
your skin and could even cause
cancer. Do not let used oil stay on
your skin for very long. Clean your
skin and nails with soap and water,
or a good hand cleaner. Wash or
properly dispose of clothing or rags
containing used engine oil. See the
manufacturer's warnings about the
use and disposal of oil products.
Used oil can be a threat to the
environment. If you change your
own oil, be sure to drain all the oil
from the filter before disposal. Never
dispose of oil by putting it in the
trash or pouring it on the ground,
into sewers, or into streams or
bodies of water. Recycle it by taking
it to a place that collects used oil.
Engine Oil Life System
When to Change Engine Oil
This vehicle has a computer system
that indicates when to change the
engine oil and filter. This is based
on a combination of factors which
include engine revolutions, engine
temperature, and miles driven.
Based on driving conditions, the
mileage at which an oil change is
indicated can vary considerably. For
the oil life system to work properly,
the system must be reset every time
the oil is changed.
On some vehicles, when the system
has calculated that oil life has been
diminished, a CHANGE ENGINE
OIL SOON message comes on to
indicate that an oil change is
necessary. SeeEngine Oil
Messages on page 5‑40. Change
the oil as soon as possible within
the next 1 000 km (600 mi).

Black plate (11,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-11
It is possible that, if driving under
the best conditions, the oil life
system might indicate that an oil
change is not necessary for up to a
year. The engine oil and filter must
be changed at least once a year
and, at this time, the system must
be reset. For vehicles without
the CHANGE ENGINE OIL
SOON message, an oil change is
needed when the OIL LIFE
REMAINING percentage is near
0%. Your dealer has trained service
people who will perform this work
and reset the system. It is also
important to check the oil regularly
over the course of an oil drain
interval and keep it at the proper
level.
If the system is ever reset
accidentally, the oil must be
changed at 5 000 km (3,000 mi)
since the last oil change.
Remember to reset the oil life
system whenever the oil is changed.How to Reset the Engine Oil
Life System
Reset the system whenever the
engine oil is changed so that the
system can calculate the next
engine oil change. Always reset the
engine oil life to 100% after every oil
change. It will not reset itself. To
reset the system on most vehicles:
1. Display the OIL LIFEREMAINING on the DIC. If the
vehicle does not have DIC
buttons, the vehicle must be in
P (Park) to access this display.
See Driver Information Center
(DIC) on page 5‑29.
2. Press and hold the SET/RESET button on the DIC, or the trip
odometer reset stem if the
vehicle does not have DIC
buttons, for more than
five seconds. The oil life
will change to 100%. On all vehicles, the Engine Oil Life
System can be reset as follows:
1. Turn the ignition to ON/RUN with
the engine off.
2. Fully press the accelerator pedal slowly three times within
five seconds.
3. Display the OIL LIFE REMAINING on the DIC. If the
display shows 100%, the system
is reset. See Driver Information
Center (DIC) on page 5‑29.
If the vehicle has a CHANGE
ENGINE OIL SOON message
and it comes back on when the
vehicle is started and/or the OIL
LIFE REMAINING is near 0%, the
engine oil life system has not been
reset. Repeat the procedure.

Black plate (26,1)GMC Yukon/Yukon XL Owner Manual - 2012
10-26 Vehicle Care
Brakes
This vehicle has disc brakes. Disc
brake pads have built-in wear
indicators that make a high-pitched
warning sound when the brake pads
are worn and new pads are needed.
The sound can come and go or be
heard all the time the vehicle is
moving, except when applying the
brake pedal firmly.
{WARNING
The brake wear warning sound
means that soon the brakes will
not work well. That could lead to
a crash. When the brake wear
warning sound is heard, have the
vehicle serviced.
Notice: Continuing to drive with
worn-out brake pads could result
in costly brake repair. Some driving conditions or climates
can cause a brake squeal when the
brakes are first applied or lightly
applied. This does not mean
something is wrong with the brakes.
Properly torqued wheel nuts are
necessary to help prevent brake
pulsation. When tires are rotated,
inspect brake pads for wear and
evenly tighten wheel nuts in the
proper sequence to torque
specifications in
Capacities and
Specifications on page 12‑2.
Brake linings should always be
replaced as complete axle sets.
Brake Pedal Travel
See your dealer if the brake pedal
does not return to normal height,
or if there is a rapid increase in
pedal travel. This could be a sign
that brake service might be
required.
Brake Adjustment
Every time the brakes are applied,
with or without the vehicle moving,
the brakes adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is
complex. Its many parts have to be
of top quality and work well together
if the vehicle is to have really good
braking. The vehicle was designed
and tested with top-quality brake
parts. When parts of the braking
system are replaced, be sure to get
new, approved replacement parts.
If this is not done, the brakes might
not work properly. For example,
installing disc brake pads that are
wrong for the vehicle, can change
the balance between the front and
rear brakes —for the worse. The
braking performance expected can
change in many other ways if the
wrong replacement brake parts are
installed.

Black plate (63,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-63
Adjust the front and rear tires to
the recommended inflation
pressure on the Tire and
Loading Information label after
the tires have been rotated. See
Tire Pressure on page 10‑56
andVehicle Load Limits on
page 9‑16.
Reset the Tire Pressure Monitor
System. See Tire Pressure
Monitor Operation on
page 10‑59.
Check that all wheel nuts are
properly tightened. See “Wheel
Nut Torque” underCapacities
and Specifications on
page 12‑2.{WARNING
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
make wheel nuts become loose
after time. The wheel could come
off and cause an accident. When
changing a wheel, remove any
rust or dirt from places where the
wheel attaches to the vehicle. In
an emergency, a cloth or a paper
towel can be used; however, use
a scraper or wire brush later to
remove all rust or dirt.
Lightly coat the center of the
wheel hub with wheel bearing
grease after a wheel change or
tire rotation to prevent corrosion
or rust build-up. Do not get
grease on the flat wheel
mounting surface or on the
wheel nuts or bolts.
When It Is Time for New
Tires
Factors, such as maintenance,
temperatures, driving speeds,
vehicle loading, and road conditions
affect the wear rate of the tires.
Treadwear indicators are one way to
tell when it is time for new tires.
Treadwear indicators appear when
the tires have only 1.6 mm (1/16 in)
or less of tread remaining. Some
commercial truck tires may not
have treadwear indicators.