2003 GMC YUKON check engine

ENGINE OVERHEATED
If the engine cooling system reaches unsafe
temperatures for operation, this message will appear in
the DIC and you will hear a chime. Stop and turn off
the vehicle as soon as it is safe to do so to avoid severe
damage. This message will clear when the engine
has cooled to a safe operating temperature.
OIL PRESSURE LOW
If low oil pressure levels occur, this message will be
displayed on the DIC and a chime will sound. Stop the
vehicle as soon as safely possible and do not operate
it until the cause of the low oil pressure has been
corrected. Check your oil as soon as possible and have
your vehicle serviced.
REDUCED ENGINE POWER
This message is displayed when the cooling system
temperature gets too hot and the engine further enters
the engine coolant protection mode.
SeeEngine Overheating on page 5-29for further
information.
BATTERY NOT CHARGING
If the battery is not charging during operation, this
message will appear on the DIC. Driving with this
problem could drain your battery. Have the electrical
system checked as soon as possible. Pressing the
select button will acknowledge this message and clear it
from the DIC display.
SERVICE AIRBAG
If there is a problem with the air bag system, this
message will be displayed on the DIC. Have a qualified
technician inspect the system for problems. Pressing
the select button will acknowledge this message
and clear it from the DIC display.
SERVICE BRAKE SYSTEM
If there is a problem with the brake system, this
message will be displayed on the DIC. If this message
appears, stop as soon as possible and turn off the
vehicle. Restart the vehicle and check for the message
on the DIC display. If the message is still displayed,
or appears again when you begin driving, the brake
system needs service.
3-65
2003 - Yukon/Yukon XL

SERVICE STABILITY
If you ever see the SERVICE STABILITY message, it
means there may be a problem with your
Stabilitrak
®system. If you see this message try to reset
the system (stop; turn off the engine; then start the engine
again). If the SERVICE STABILITY message still comes
on, it means there is a problem. You should see your
dealer for service. The vehicle is safe to drive, however,
you do not have the benefit of Stabilitrak
®, so reduce your
speed and drive accordingly.
STABILITY SYS ACTIVE
You may see the STABILITY SYS ACTIVE message on
the DIC. It means that an advanced computer-controlled
system has come on to help your vehicle continue to go
in the direction in which you’re steering.
Stabilitrak
®activates when the computer senses that
your vehicle is just starting to spin, as it might if you hit a
patch of ice or other slippery spot on the road. When the
system activates, you may hear a noise or feel a vibration
in the brake pedal. This is normal. When the STABILITY
SYS ACTIVE message is on, you should continue to
steer in the direction you want to go. The system is
designed to help you in bad weather or other difficult
driving situations by making the most of whatever road
conditions will permit.
STABILITY SYS DISABLED
The STABILITY SYS DISABLED message will turn on
when you press the Stabilitrak®button, or when the
stability control has been automatically disabled. To limit
wheel spin and realize the full benefits of the stability
enhancement system, you should normally leave
Stabilitrak
®on. However, you should turn Stabilitrak®off
if your vehicle gets stuck in sand, mud, ice or snow and
you want to“rock”your vehicle to attempt to free it, or if
you are driving in extreme off-road conditions and require
more wheel spin. SeeIf You Are Stuck: In Sand, Mud, Ice
or Snow on page 4-52. To turn the Stabilitrak
®system
back on press the Stabilitrak®button again. There are
four conditions that can cause this message to appear.
One condition is overheating, which could occur if
Stabilitrak
®activates continuously for an extended period
of time. The message will also be displayed if the brake
system warning light is on. SeeBrake System Warning
Light on page 3-43. The message could be displayed if
the stability system takes longer than usual to complete
its diagnostic checks due to driving conditions. Also, if an
engine or vehicle related problem has been detected, and
the vehicle needs service, the message will appear.
The message will turn off as soon as the conditions that
caused the message to be displayed are no longer
present.
3-70
2003 - Yukon/Yukon XL

Audio System(s)
Notice:Before you add any sound equipment to
your vehicle–like a tape player, CB radio, mobile
telephone or two-way radio–be sure you can add
what you want. If you can, it’s very important to do it
properly. Added sound equipment may interfere with
the operation of your vehicle’s engine, radio or other
systems, and even damage them. Your vehicle’s
systems may interfere with the operation of sound
equipment that has been added improperly.
So, before adding sound equipment, check with
your dealer and be sure to check federal rules
covering mobile radio and telephone units.
Your audio system has been designed to operate easily
and to give years of listening pleasure. You will get
the most enjoyment out of it if you acquaint yourself with
itfirst. Figure out which radio you have in your vehicle,
find out what your audio system can do and how to
operate all of its controls to be sure you’re getting the
most out of the advanced engineering that went into it.Your vehicle may have a feature called Retained
Accessory Power (RAP). With RAP, you can play your
audio system even after the ignition is turned off.
See“Retained Accessory Power (RAP)”underIgnition
Positions on page 2-19.
Setting the Time for Radios without
Radio Data Systems (RDS)
Press and hold the HR or MIN arrow for two seconds.
Then press the HR (down) arrow until the correct hour
appears on the display. Press and hold the MIN (up)
arrow until the correct minute appears on the display. The
time may be set with the ignition on or off.
3-71
2003 - Yukon/Yukon XL

with the traffic and allow realistic following distances,
you will eliminate a lot of unnecessary braking.
That means better braking and longer brake life.
If your engine ever stops while you’re driving, brake
normally but don’t pump your brakes. If you do,
the pedal may get harder to push down. If your engine
stops, you will still have some power brake assist.
But you will use it when you brake. Once the power
assist is used up, it may take longer to stop and
the brake pedal will be harder to push.
Anti-lock Brake System
Your vehicle has anti-lock brakes. ABS is an advanced
electronic braking system that will help prevent a
braking skid.
When you start your engine and begin to drive away,
your anti-lock brake system will check itself. You
may hear a momentary motor or clicking noise while
this test is going on. This is normal.If there’s a problem with
the anti-lock brake system,
this warning light will
stay on. SeeAnti-Lock
Brake System Warning
Light on page 3-44.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there’s a DRP problem,
both the brake and ABS warning lights will come on
accompanied by a 10-second chime. The lights
and chime will come on each time the ignition is turned
on until the problem is repaired. See your dealer for
service.
4-7
2003 - Yukon/Yukon XL

Remember: Anti-lock doesn’t change the time you need
to get your foot up to the brake pedal or always
decrease stopping distance. If you get too close to the
vehicle in front of you, you won’t have time to apply
your brakes if that vehicle suddenly slows or stops.
Always leave enough room up ahead to stop, even
though you have anti-lock brakes.
Using Anti-Lock
Don’t pump the brakes. Just hold the brake pedal down
rmly and let anti-lock work for you. You may feel
the brakes vibrate, or you may notice some noise, but
this is normal.
Braking in Emergencies
With anti-lock, you can steer and brake at the same
time. In many emergencies, steering can help you more
than even the very best braking.
Supplemental Brake Assist System
If your vehicle has vacuum assist power brakes, it is also
equipped with a supplemental brake assist system
that supplies additional vacuum to the vacuum brake
booster if engine vacuum is reduced. Under certain
conditions, the supplemental brake assist system may
run briey after starting your vehicle or when you
apply and release the brake pedal and it may continueto run even after you have removed your foot from the
brake pedal. When the supplemental brake assist
system is operating, you may hear a motor running or
feel a slight vibration in the steering wheel or brake
pedal. This indicates that the supplemental brake assist
system is working to supply additional vacuum for
your vacuum assist power brakes. This is a normal
operation of your brake system and does not require that
the brake system be serviced.
Each time you start your vehicle and accelerate to
10 mph, the supplemental brake assist system
will perform a self-diagnostic check of the system and
you may hear or feel the supplemental brake assist
motor run briey. While you are driving your vehicle, the
supplemental brake assist system monitors itself to
ensure that it is operating properly. If there is a problem
with the supplemental brake assist system, the
SERVICE BRAKE BOOSTER message will be displayed
on the Driver Information Center. SeeDIC Warnings
and Messages on page 3-64.
If your supplemental brake assist system runs every
time you apply and release the brake pedal or you notice
that the brake pedal has suddenly become much
harder to push and the vehicle takes longer to stop, you
should have your vehicle serviced as soon as possible.
4-9
2003 - Yukon/Yukon XL

Reduce your speed according to your speedometer, not
to your sense of motion. After driving for any distance
at higher speeds, you may tend to think you are
going slower than you actually are.
Before Leaving on a Long Trip
Make sure you’re ready. Try to be well rested. If you
must start when you’re not fresh—such as after a day’s
work—don’t plan to make too many miles thatrst
part of the journey. Wear comfortable clothing and shoes
you can easily drive in.
Is your vehicle ready for a long trip? If you keep it
serviced and maintained, it’s ready to go. If it needs
service, have it done before starting out. Of course,
you’llnd experienced and able service experts in GM
dealerships all across North America. They’ll be
ready and willing to help if you need it.
Here are some things you can check before a trip:
Windshield Washer Fluid:Is the reservoir full? Are
all windows clean inside and outside?
Wiper Blades:Are they in good shape?
Fuel, Engine Oil, Other Fluids:Have you checked
all levels?
Lamps:Are they all working? Are the lenses clean?
Tires:They are vitally important to a safe,
trouble-free trip. Is the tread good enough for
long-distance driving? Are the tires all inated to the
recommended pressure?
Weather Forecasts:What’s the weather outlook
along your route? Should you delay your trip a
short time to avoid a major storm system?
Maps:Do you have up-to-date maps?
Highway Hypnosis
Is there actually such a condition as“highway
hypnosis”? Or is it just plain falling asleep at the wheel?
Call it highway hypnosis, lack of awareness, or
whatever.
There is something about an easy stretch of road with
the same scenery, along with the hum of the tires on the
road, the drone of the engine, and the rush of the
wind against the vehicle that can make you sleepy. Don’t
let it happen to you! If it does, your vehicle can leave
the road inless than a second,and you could crash and
be injured.
4-44
2003 - Yukon/Yukon XL

If you drive regularly in steep country, or if you’re
planning to visit there, here are some tips that can make
your trips safer and more enjoyable. SeeOff-Road
Driving with Your Four-Wheel-Drive Vehicle on
page 4-22for information about driving off-road.
Keep your vehicle in good shape. Check alluid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you go
down a steep or long hill.
{CAUTION:
If you don’t shift down, your brakes could get
so hot that they wouldn’t work well. You would
then have poor braking or even none going
down a hill. You could crash. Shift down to let
your engine assist your brakes on a steep
downhill slope.
{CAUTION:
Coasting downhill in NEUTRAL (N) or with the
ignition off is dangerous. Your brakes will have
to do all the work of slowing down. They could
get so hot that they wouldn’t work well. You
would then have poor braking or even none
going down a hill. You could crash. Always
have your engine running and your vehicle in
gear when you go downhill.
Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your
engine and transmission, and you can climb the hill
better.
Stay in your own lane when driving on two-lane
roads in hills or mountains. Don’t swing wide or
cut across the center of the road. Drive at speeds
that let you stay in your own lane.
4-46
2003 - Yukon/Yukon XL

{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You can’t see it or
smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle, especially any that is
blocking your exhaust pipe. And check around
again from time to time to be sure snow
doesn’t collect there.
Open a window just a little on the side of the
vehicle that’s away from the wind. This will
help keep CO out.Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery charged. You will need a
well-charged battery to restart the vehicle, and possibly
for signaling later on with your headlamps. Let the
heater run for a while.
Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine
again and repeat this only when you feel really
uncomfortable from the cold. But do it as little as
possible. Preserve the fuel as long as you can. To help
keep warm, you can get out of the vehicle and do
some fairly vigorous exercises every half hour or so until
help comes.
4-51
2003 - Yukon/Yukon XL