2003 GMC YUKON DENALI warning

You may see highway signs on mountains that
warn of special problems. Examples are long
grades, passing or no-passing zones, a falling rocks
area or winding roads. Be alert
to these and take
appropriate action.
Winter Driving
Here are some tips for winter driving:
Have your vehicle in good shape for winter.
You may want to put winter emergency supplies in
your
vehicle.
Include an ice scraper, a small brush or broom, a
supply of windshield washer fluid, a rag, some winter
outer clothing, a small shovel, a flashlight, a red
cloth and a couple of reflective warning triangles. And,
if
you will be driving under severe conditions, include a
small bag of sand, a piece of old carpet or a couple of
burlap bags
to help provide traction. Be sure you
properly secure these items in your vehicle.
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Backing Up
Hold the bottom of the steering wheel with one hand.
Then,
to move the trailer to the left, just move that hand
to the left. To move the trailer to the right, move your
hand
to the right. Always back up slowly and, if possible,
have someone guide you.
Making Turns
Notice: Making very sharp turns while trailering
could
cause the trailer to come in contact with the
vehicle. Your vehicle could
be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns
than normal.
Do this so your trailer won’t strike
soft shoulders, curbs, road signs, trees or other objects.
Avoid jerky or sudden maneuvers. Signal well in
advance.
Turn Signals When Towing a Trailer
The arrows on your instrument panel will flash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also flash, telling other drivers
you’re about
to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument panel will flash for turns even
if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
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you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade.
If you don’t shift
down, you might have to use your brakes
so much that
they would get hot and no longer work well.
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).
You may also want
to activate the tow/haul mode if the
transmission shifts
too often. See “Tow/Haul Mode”
under Towing a Trailer
on page 4-47.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes.
If you turn your
engine
off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar
to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine
off. If you do get
the overheat warning, see Engine Overheating
on
page 5-25.

A. Engine Air CleanedFilter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator
D. Engine Qii Dipstick
E. Engine Oil Fill
F. Automatic Transmission Dipstick
G. Fan
H. Remote Negative (-) Terminal (GND)
I. Remote Positive (+) Terminal
J. Power Steering Fluid Reservoir (Out of View)
K. Brake Master Cylinder Reservoir
L. Underhood Fuse Block
M. Battery
N. Windshield Washer Fluid Reservoir
Before closing the hood, be sure all filler caps are on
properly. Pull down the hood and close
it firmly.
Engine Oil
If the CHECK OIL LEVEL message appears on the
instrument cluster, it means you need to check
your engine oil level right away.
For more information, see “CHECK OIL LEVEL” under
DIC Warnings and Messages on page 3-52.
You should check your engine oil level regularly; this is
an added reminder.
Checking Engine Oil
It’s a good idea to check your engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick has a yellow loop handle and
is located in the engine
compartment on the
passenger’s side of the
vehicle. See Engine
Compartment Overview on
page
5- 12 for more
information on location.
Turn
off the engine and give the oil several minutes to
drain back into the oil pan. If you don’t, the oil
dipstick might not show the actual level.
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.
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How to Reset the CHANGE ENGINE OIL
Message
The GM Oil Life System calculates when to change
your engine oil and filter based on vehic!e
use. Anytime
your oil is changed, reset the system
so it can
calculate when the next oil change is required.
If a
situation occurs where you change your
oil prior to a
CHANGE ENGINE OIL message being turned on, reset
the system.
To reset the CHANGE ENGINE
OIL message, see “GM
Oil Life System” under DIC Operation and Displays
on page 3-43 for vehicles equipped with the DIC, or do
the following:
1. Turn the ignition key to RUN with the engine off.
2. Fully press and release the accelerator pedal three
If the OIL LIFE RESET message flashes for
10 seconds,
the system is reset.
If the system does not reset, try the procedure once
again. If it still does not reset, see your dealer for
service. times
within five seconds.
What to Do with Used Oil
Used engine oil contains certain elements that may be
unhealthy for your skin and could even cause cancer.
Don’t 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, pouring it on the ground, into sewers, or into
streams or bodies of water. Instead, recycle it by
taking it to a place that collects used oil. If you have a
problem properly disposing of your used oil, ask
your dealer, a service station or a local recycling center
for help.
Engine Air Cleaner/Filter
The engine air cleanedfilter assembly has an air filter
restriction indicator that lets you know when the engine
air cleaner/filter is dirty and needs to be serviced.
The air filter restriction indicator is located on the air
filter assembly cover. See Engine Compartment
Overview
on page 5-72 for more information on location.
See Part
B: Owner Checks and Services on page 6-10
to determine when to check the air filter restriction
indicator.
5-1 7

The following explains your cooling system and how to
add coolant when it is low. If you have a problem
with engine overheating, see Engine Overheating
on
page 5-25.
A 50/50 mixture of clean, drinkable water and
DEX-COOL@ coolant will:
Give freezing protection down to -34°F (-37°C).
Give boiling protection up to 265°F (129°C).
Protect against rust and corrosion.
Help keep the proper engine temperature.
e Let the warning lights and gages work as they
should.
Notice: When adding coolant, it is important that
you use only
DEX-COOL@ (silicate-free) coolant.
If coolant other than DEX-COOL@ is added to the
system, premature engine, heater core or radiator
corrosion may result. In addition, the engine coolant
will require change sooner
-- at 30,000 miles
(50,000 km) or 24 months, whichever occurs first.
Damage caused by the use of coolant other than
DEX-COQL.@ is not covered by your new vehicle
warranty.
What to Use
Use a mixture of one-half clean, drinkable water and
one-half DEX-COOL@ coolant which won’t damage
aluminum parts.
!f YOU uss this coolant mixture,
you don’t need
to add anything else.
Adding c..ly
c water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can boil before the proper coolant mixture will. Your
vehicle’s coolant warning system
is set for the
proper coolant mixture. With plain water or the
wrong mixture, your engine could get too hot
but you wouldn’t get the overheat warning.
Your engine could catch fire and you or others
could be burned. Use a
50/50 mixture of clean,
drinkable water and DEX-COQL@ coolant.
Notice: If you use an improper coolant mixture,
your engine could overheat and be badly damaged.
The repair cost wouldn’t be covered by your
warranty. Too much water
in the mixture can freeze
and crack the engine, radiator, heater core and
other parts.
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If you have to add coolant more than four times a year,
have your dealer check your cooling system.
Notice: If you use the proper coolant, you don’t
have to add extra inhibitors or additives which claim
to improve the system. These can be harmful.
Checking Coolant
The coolant surge tank is
located in the engine
compartment on the
passenger’s side of the
vehicle.
.
1 ~ ---lg the surge tanl- ,xessure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you badly. Never turn the surge tank pressure
cap
- even a little - when the engine and
radiator are hot.
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the FULL
COLD mark.
If the LOW COOLANT
LEVEL message comes on and
stays on, it means you’re low on engine coolant.
See “Low Coolant Level” under
DIC Warnings and
Messages on page
3-52.
See Engine Compartment Overview on page 5-12 for
more information on location.
5-24

Adding Coolant
If you need more coolant, add the proper DEX-COOL@
coolant mixture
at the surge tank, but only when the
engine
is cool.
1 “J can be burned if you sb... coolant on hot
engine parts. Coolant contains ethylene glycol, and
it will burn if the engine parts are hot
enough. Don’t spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight.
Coolant Surge Tank Pressure Cap
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. See Engine
Compartment Overview on page
5-12 for more
information on location.
Notice: Your pressure cap is a pressure-type cap
and must be tightly installed to prevent coolant
loss
and possible engine damage from overheating.
See “Capacities and Specifications” for more
information.
Engine Overheating
You will find a coolant temperature gage on your
vehicle’s instrument panel. See Engine Coolant
Temperature Gage
on page 3-36. in addition, yoti ill
find a LOW COOLANT, ENGINE COOLANT HOT,
ENGINE OVERHEATED and a REDUCED ENGINE
POWER message in the DIC on the instrument panel.
See DIC Warnings and Messages on page
3-52.
Overheated Engine Protection
Operating Mode
If an overheated engine condition exists and the
REDUCED ENGINE POWER message is displayed, an
overheat protection mode which alternates firing
groups of cylinders helps prevent engine damage.
In
this mode, you will notice a loss in power and engine
performance. This operating mode allows your vehicle to
be driven
to a safe place in an emergency. Driving
extended miles (km) and/or towing a trailer in the
overheat protection mode should be avoided.
Notice: After driving in the overheated engine
protection operating mode, to avoid engine damage,
allow the engine to cool before attempting any repair.
The engine oil will be severely degraded. Repair the cause of coolant
loss, change the oil and reset the oil
life system. See “Engine Oil” in the Index.
5-25

If No Steam Is Coming From Your
Engine
An overheat warning, along with a low coolant message,
can indicate a serious problem. See
Low Coolant
Level Warning Message under DIC Warnings and
Messages
on page 3-52.
If you get an engine overheat warning but see or hear
no steam, the problem may not be
too serious.
Sometimes the engine can get a little
too hot when you:
0 Climb a long hill on a hot day.
Stop after high-speed driving.
0 Idle for long periods in traffic.
0 Tow a trailer. See Towing a Trailer on page 4-47.
If you get the overheat warning with no sign of steam, try
this for a minute or so:
1. Turn on your heater to full hot at the highest fan
speed and open the window as necessary.
If you no longer have the overheat warning, you can
drive. Just
to be safe, drive slower for about 10 minutes.
If the warning doesn’t come back on, you can drive
normally.
If the warning continues, pull over, stop, and park your
vehicle right away.
If there’s still no sign of steam, push down the
accelerator until the engine speed is about twice as fast
as normal idle speed for at least three minutes while
you’re parked. If you still have the warning, turn
off the
engine and get everyone out
of the vehicle until it
cools down. Also, see “Overheated Engine Protection
Operating Mode” listed previously in this section.
You may decide not
to lift the hood but to get service
help right away.
2. If you’re in a traffic jam, shift to NEUTRAL (N);
otherwise, shift to the highest gear while
driving
- DRIVE (D).
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