2003 GMC YUKON DENALI trailer

Light On Steady - An emission control system
malfunction has been detected on your vehicle.
Dealer or qualified service center diagnosis
and service may be required.
If the Light is Flashing
The following may prevent more serious damage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
Avoiding steep uphill grades.
If you are towing a trailer, reduce the amount of
cargo being hauled as soon as it is possible.
If the light stops flashing and remains on steady, see “If
the Light
Is On Steady” following.
If the light continues to flash, when
it is safe to do so,
stop the vehicle. Find a safe place to park your vehicle.
Turn the key
off, wait at least 10 seconds and restart
the engine. If the light remains on steady, see
“If
the Light Is On Steady” following. If the light is still
flashing, follow the previous steps, and drive the vehicle
to your dealer or qualified service center for service.
If the Light Is On Steady
You may be able to correct the emission system
malfunction by considering the following:
Did
you recently put fuel into your vehicle?
If so, reinstall the fuel cap, making sure to fully install
the cap. See Filling
Your Tank on page 5-7. The
diagnostic system can determine
if the fuel cap has
been left
off or improperly installed. A loose or missing
fuel cap will allow fuel to evaporate into the atmosphere.
A few driving trips with the cap properly installed
should turn the light
off.
Did you just drive through a deep puddle of water?
If so, your electrical system may be wet. The condition
will usually be corrected when the electrical system
dries out. A few driving trips should turn the light
off.
Have you recently changed brands of fuel?
If so, be sure to fuel your vehicle with quality fuel. See
Gasoline Octane
on page 5-5. Poor fuel quality will
cause your engine not to run as efficiently as designed.
You may notice this as stalling after start-up, stalling
when you put the vehicle into gear, misfiring, hesitation
on acceleration or stumbling on acceleration. (These
conditions may go away once the engine is warmed up.)
This will be detected by the system and cause the
light to turn on.
If you experience one or more of these conditions,
change the fuel brand you use. It will require at least
one full tank
of the proper fuel to turn the light off.

Tow/HauI Mode Light
I
This light is displayed
when the tow/haul mode
has been activated.
For more information, see "Tow/Haul Mode" under
Towing a Trailer on page 4-47.
Fuel Gage
United States
Canada
When the ignition is on, the fuel gage tells you about
how much fuel you have left in your tank.
The gage will first indicate empty before you are out of
fuel, and you should get more fuel as
soon as
possible.
Here are some situations you may experience with your
fuel gage. None of these indicate a problem with the
fuel gage.
At the gas station, the fuel pump shuts off before
the gage reads full.
It takes a little more or less fuel to fill up than the
fuel gage indicated. For example, the gage may
have indicated the tank was half full, but
it actually
took a little more or less than half the tank's
capacity to
fill the tank.
The gage goes back to empty when you turn off the
ignition.
Low Fuel Warning Light
The light next to the fuel gage will come on briefly when
you are starting the engine.
This light comes on when the fuel tank is
low on fuel.
To turn it off, add fuel to the fuel tank. See Fuel on
page 5-5.
3-42

FUEL LEVEL LOW
If the fuel level is low, this message will appear on the
DIC and you will hear a chime. Refuel as soon as
possible. Pressing the select button will acknowledge
this message immediately and clear it from the DIC
display. It will also clear itself after
10 seconds until the
next ignition cycle. The low fuel light near the fuel
gage will still remain on in either case.
CHECK WASHER FLUID
If the washer fluid level is low, this message will appear
on the DIC. Adding washer fluid will clear the message.
Pressing the select button will acknowledge this
message and clear it from the DIC display. This
message will clear itself after
10 seconds until the next
igntion cycle.
TRANSMISSION HOT
If the transmission fluid temperature becomes high, the
message center will display this message.
When the transmission enters the protection mode, you
may notice a change in the transmission shifting
patterns. When the transmission fluid temperature
returns
to normal, the display will turn off and the
transmission shifting patterns will return
to normal.
Notice: If you keep driving your vehicle with the
transmission
TRANS FLUID HOT message
displayed, you can damage the transmission. This
could lead to costly repairs that may not be covered
under your warranty.
The following situations can cause the transmission to
operate at higher temperatures:
Towing a trailer
@ Hot outside air temperatures
Hauling a large or heavy load
Low transmission fluid level
High transmission fluid level
Restricted air flow to the radiator.
A temporary solution
to hotter transmission operating
temperatures may be
to let the transmission cool down.
If the transmission is operated at higher temperatures
on a frequent basis, see Scheduled Maintenance
on page 6-5 for the proper transmission maintenance
intervals.
TRANS HOT IDLE ENGINE
If the transmission fluid in the vehicle gets hot, this
message will appear on the DIC along with a continuous
chime. Driving with the transmission fluid temperature
high can cause damage
to the vehicle.
3-55

Section 4 Driving Your Vehicle
Your Driving. the Road. and Your Vehicle .......... 4-2
Defensive Driving
........................................... 4.2
Drunken Driving
............................................. 4-2
Control of a Vehicle
........................................ 4-5
Braking
......................................................... 4-6
Stabilitrak@ System
......................................... 4-9
Steering
...................................................... 4-11
Off-Road Recovery
....................................... 4-13
Passing
....................................................... 4-13
Loss of Control ............................................. 4-15
Operating Your All-Wheel-Drive Vehicle Off
Paved Roads
............................................ 4-16
Driving at Night
............................................ 4-28
Driving in Rain and on Wet Roads
.................. 4-29 City Driving
.................................................. 4-32
Before Leaving on a Long Trip
....................... 4-34
Highway Hypnosis
........................................ 4-35
Winter Driving
.............................................. 4.37
Towing .......................................................... 4.44
Towing Your Vehicle
..................................... 4-44
Recreational Vehicle Towing
........................... 4-44
Loading Your Vehicle
........... ................. 4.44
AutorideTM
.............................. ............. 4-46
Trailer Recommendations
............................... 4-47
Towing a Trailer
...................... ...... 4-47
Freeway Driving
4-33 -r ...........................................
Hill and Mountain Roads ................................ 4-35
If You Are Stuck: In Sand, Mud, Ice or Snow
........ 4-41
4-
1

Automatic Level Control
The automatic level control rear suspension comes as a
part of the AutorideTMsuspension. See AutorideTM on
page
4-46.
This type of level control is fully automatic and will
provide a better leveled riding position as well as better
handling under a variety of passenger and loading
conditions. An air compressor connected
to the rear
shocks will raise or lower the rear of the vehicle
to maintain proper vehicle height. The system is
activated when the ignition key
is turned to RUN and
will automatically adjust vehicle height thereafter.
The system may exhaust (lower vehicle height) for up
to
10 minutes after the ignition key has been turned to
OFF. You may hear the air compressor operating when
the height is being adjusted.
If a weight-distributing hitch is being used, it is
recommended
to allow the shocks to inflate, thereby
leveling the vehicle prior to adjusting the height.
AutorideTM
The AutorideTM feature provides superior vehicle ride
and handling under a variety
of passenger and loading
conditions.
The system is fully automatic and
uses a computer
controller
to continuously monitor vehicle speed, wheel
to body position, IifVdive and steering position of the
vehicle. The controller then sends signals to each shock
absorber
to independently adjust the damping level to
provide the optimum vehicle ride.
AutorideTM also interacts with the towlhaul mode that,
when activated, will provide additional control of
the shock absorbers. This additional control results in
better ride and handling characteristics when the vehicle
is loaded or towing a trailer. See "Tow/Haul Mode"
under Towing a Trailer on page
4-47 for more
information.
4-46

Trailer Recommendations
You must subtract your hitch loads from the Cargo
Weight Rating (CWR). CWR is the maximum weight of
the load your vehicle can carry.
It doesn’t include
the weight of the people inside. But you can figure about
150 Ibs. (68 kg) for each seat. The total cargo load
must
not be more than your vehicle’s CWR.
Weigh your vehicle with the trailer attached,
so that you
won’t
go over the GVWR or GAWR. If you are using
a weight-distributing hitch, weigh the vehicle without the
spring bars in place.
You’ll get the best performance if you spread out the
weight of your load the right way, and
if you choose the
correct hitch and trailer brakes.
For more information, see
Towing a Trailer on
page 4-47.
Towing a Trailer
Is
IOU don’_ Ase e correct equipment anc-
drive properly, you can lose control when you
pull a trailer. For example, if the trailer is too
heavy, the brakes may not work well
-- or even
at all.
You and your passengers could be
seriously injured. Pull a trailer only
if you have
followed all the steps
in this section. Ask your
dealer for advice and information about towing
a trailer with your vehicle.
Nofice: Pulling a trailer improperly can damage
your vehicle and result
in costly repairs not covered
by your warranty.
To pull a trailer correctly, follow
the advice
in this part, and see your dealer for
important information about towing a trailer with
your vehicle. Additional rear axle maintenance
is required for a vehicle used to tow a trailer. See
“Scheduled Maintenance Services” in the Index.
4-47

To identify the trailering capacity for your vehicle, you
should read the information in “Weight of the Trailer” that
appears later in this section.
If yours was built with trailering options, as many are,
it’s ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, durability and fuel economy.
Successful, safe trailering takes correct equipment, and
it has
to be used properly.
That’s the reason for this part. In it are many time-tested,
important trailering tips and safety rules. Many of
these are important for your safety and that of your
passengers.
So please read this section carefully before
you pull a trailer.
0
0
If You Do Decide To Pull A Trailer
If you do, here are some important points:
There are many different laws, including speed limit
restrictions, having
to do with trailering. Make sure
your rig will be legal, not only where you live
but also where you’ll be driving.
A good source for
this information can be state or provincial police. Consider using a
sway control
if your trailer will
weigh
5,000 Ibs. (2 270 kg) or less. You should
always use a sway control
if your trailer will weigh
more than
5,000 Ibs. (2 270 kg). You can ask a
hitch dealer about sway controls.
Don’t tow a trailer at all during the first
500 miles
(800 km) your new vehicle is driven. Your engine,
axle or other parts could be damaged.
Then, during the first
500 miles (800 km) that you
tow a trailer, don’t drive over
50 mph (80 km/h)
and don’t make starts at full throttle. This helps your
engine and other parts of your vehicle wear in at
the heavier loads.
You can tow in
DRIVE (D). You may want to shift
the transmission
to THIRD (3) or, if necessary, a
lower gear selection
if the transmission shifts
too often (e.g., under heavy loads and/or hilly
conditions). See “Tow/Haul Mode” under Towing
a
Trailer on page 4-47.
Three important considerations have to do with weight:
0 the weight of the trailer,
the weight of the trailer tongue
0 and the weight on your vehicle’s tires.
4-48

Tow/Haul Mode
The tow/haul feature assists when pulling a heavy trailer
or a large or heavy load. The purpose
of the tow/haul
mode
is to:
Reduce the frequency and improve the predictability
of transmission shifts when pulling a heavy trailer or
a large or heavy load.
Provide the same solid shift feel when pulling a
heavy trailer or a large or heavy load as when
the vehicle is unloaded.
Improve control of vehicle speed while requiring
less throttle pedal activity when pulling a heavy
trailer or a large or heavy load.
Your vehicle is provided with a button at the end of the
shift lever which when pressed enables tow/haul.
When the button is pressed, a light on the instrument
panel will illuminate
to indicate that tow/haul has
been selected. Tow/haul may be turned
off by pressing
the button again, at which time the indicator light on
the instrument panel will turn off. The vehicle will
automatically turn off tow/haul every time it is started. Tow/haul
is designed
to be most effective when the
vehicle and trailer combined weight is at least
75 percent
of the vehicle’s Gross Combination Weight Rating
(GCWR). See Weight
of the Trailer later in this section.
Tovdhaul is mcst useful wder the f~l!~~ing driving
conditions:
When pulling a heavy trailer or a large or heavy
0 When pulling a heavy trailer or a large or heavy
load through rolling terrain.
load
in stop and go traffic.
When pulling a heavy trailer or a large or heavy
load in busy parking
lots where improved low
speed control of the vehicle is desired.
Operating the vehicle in tow/haul when lightly loaded or
with no trailer at all will not cause damage. However,
there is no benefit
to the selection of tow/haul when the
vehicle is unloaded. Such a selection when unloaded may result in unpleasant engine and transmission driving
characteristics and reduced fuel economy. Tow/haul
is recommended only when pulling a heavy trailer or a
large or heavy load.
4-49