2003 GMC SIERRA DENALI check engine

Here’s how to avoid setting off the alarm by accident:
If you don’t want to activate the theft-deterrent
system, the vehicle should be locked with the door
key after the doors are closed.
Always unlock a door with a key, or use the remote
keyless entry transmitter. Unlocking a door any
other way will set
off the alarm if the system
has been armed.
If you set off the alarm by accident, unlock any door
with the key. You can also turn
off the alarm by pressing
UNLOCK on the remote keyless entry transmitter or
by placing the key in the ignition and turning it to
START.
Testing the Alarm
The alarm can be tested by following these steps:
1. From inside the vehicle, lower the driver’s window
and open the driver’s door.
2. Activate the system by locking the doors with the
power door lock switch while the door is open, or
with the remote keyless entry transmitter.
3. Get out of the vehicle, close the door and wait for
the security message
to go out.
4. Then reach in through the window, unlock the door
with the manual door lock and open the door. This
should set
off the alarm. If the
alarm does not sound and the headlamps do not
flash, you may have the feature turned
off. See DIC
Operation and Displays on page 3-43 for more
information.
Passlock@
Your vehicle is equipped with the
Passlock@ theft-deterrent system.
Passlock@ is a passive theft-deterrent system.
Passlock@ enables fuel
if the ignition lock cylinder is
turned with a valid key.
If a correct key is not used or the
ignition lock cylinder is tampered with, fuel is disabled.
If the engine stalls and the security light flashes,
wait until the light stops flashing before trying to restart
the engine. Remember
to release the key from
START as soon as the engine starts.
If the engine is running and the security light comes on,
you will be able
to restart the engine if you turn the
engine
off. However, your Passlock@ system is
not working properly and must be serviced by your
dealer. Your vehicle is not protected by Passlock@ at this
time. You may also want to check the fuse (see
Fuses and Circuit Breakers on page 5-95.) See your
dealer for service.
In an emergency, call the GM Roadside Assistance
Center. See
Roadside Assistance Program on page 7-5
under Customer Assistance Information.
2-1 4

When starting your engine in very cold weather (below
0°F or -18"C), do this:
Engine Coolant Heater
1. With your foot off the accelerator pedal, turn the
ignition key to START and hold it there up to
15 seconds. When the engine starts, let go of
the key.
2. If your engine still won't start (or starts but then
stops), it could be flooded with too much gasoline.
Try pushing your accelerator pedal all the way to the
floor and holding
it there as you hold the key in
START for about three seconds. When the engine
starts, let go of the key and accelerator. If the
vehicle starts briefly but then stops again, do the
same thing, but this time keep the pedal down
for five or six seconds. This clears the extra
gasoline from the engine.
Notice: Your engine is designed to work with the
electronics in your vehicle.
If you add electrical
parts or accessories, you could change the way the
engine operates. Before adding electrical equipment,
check with your dealer.
If you don't, your engine
might not perform properly. In
very cold weather,
0°F (-18°C) or colder,
the engine coolant heater
can help. You'll get
easier starting and better
fuel economy during
engine warm-up. Usually,
the coolant heater
should be plugged in a
minimum of four hours
prior to starting your
vehicle.
At temperatures above
32°F (OOC), use of the coolant
heater is not required.
2-1 7

Warning Lights, Gages and
Indicators
This part describes the warning lights and gages that
may be on your vehicle. The pictures will help you
locate them.
Warning lights and gages can signal that something is
wrong before it becomes serious enough
to cause
an expensive repair or replacement. Paying attention to
your warning lights and gages could also save you
or others from injury.
Warning lights come on when there may be or is a
problem with one of your vehicle’s functions.
As you will
see in the details on the next few pages, some
warning lights come on briefly when you start the
engine just to let you know they’re working. If you are
familiar with this section, you should not be alarmed
when this happens. Gages can
indicate when there may be or is a problem
with one of your vehicle’s functions. Often gages
and warning lights work together
to let you know when
there’s a problem with your vehicle.
When one of the warning lights comes on and stays on
when you are driving, or when one of the gages
shows there may be a problem, check the section that
tells you what to do about
it. Please follow this
manual’s advice. Waiting to do repairs can be
costly
- and even dangerous. So please get to know
your warning lights and gages. They’re a big help.
Your vehicle also has a driver information system that
works along with the warning lights and gages. See
Driver lnformation Center (DIC) on page 3-43.
3-24

Battery Warning Light Voltmeter Gage
If this light is displayed
when the engine is
running, you may have a
problem with your charging
system.
The battery display will also stay on while the key is in
RUN until the engine is started.
If the light stays on after starting the engine it could
indicate a problem with the generator drive belt, or some
other charging system problem. Have it checked right
away. Driving with this light displayed could drain
your battery.
If you must drive a short distance with this light
displayed, it helps to turn
off all your accessories, such
as the radio and the air conditioner. When your
engine is not running, but the ignition is in
RUN, this gage shows your battery’s state of charge in
DC volts.
When the engine is running, the gage shows the
condition of the charging system. Readings between the
low and high warning zones indicate the normal
operating range.
Readings in the low warning zone may occur when a
large number
of electrical accessories are operating in
the vehicle and the engine is left at an idle for an
extended period. This condition
is normal since the
charging system is not able to provide full power
at engine idle.
As engine speeds are increased, this
condition should correct itself as higher engine speeds
allow the charging system to create maximum power.
3-33

Malfunction Indicator Lamp
Check Engine Light
Your vehicle is equipped
with a computer which
monitors operation of the
fuel, ignition and emission
control systems.
I I
This system is called OBD I1 (On-Board
Diagnostics-Second Generation) and is intended to
assure that emissions are at acceptable levels for the
life of the vehicle, helping to produce a cleaner
environment. The Check Engine light comes on to
indicate that there is a problem and service is required.
Malfunctions often will be indicated by the system
before any problem is apparent. This may prevent more
serious damage to your vehicle. This system is also
designed to assist your service technician in correctly
diagnosing any malfunction.
Notice: If you keep driving your vehicle with this
light on, after a while, your emission controls
may not work as well, your fuel economy may not
be as good and your engine may not
run as
smoothly. This could lead to costly repairs that may not be covered by your warranty.
Notice: Modifications made to the engine,
transmission, exhaust, intake or fuel system of your
vehicle or the replacement of the original tires
with other than those of the same Tire Performance
Criteria (TPC) can affect your vehicle’s emission
controls and may cause this light to come on.
Modifications to these systems could lead to costly
repairs not covered by your warranty. This may
also result in a failure to
pass a required Emission
Inspection/Maintenance test.
This light should come on, as a check to show you it is
working, when the ignition is on and the engine is
not running. If the light doesn’t come on, have it
repaired. This light will also come on during a
malfunction in one of two ways:
Light Flashing - A misfire condition has been
detected.
A misfire increases vehicle emissions
and may damage the emission control system on
your vehicle. Dealer or qualified service center
diagnosis and service may be required.
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.
3-38

If the Light is Flashing
The following may prevent more serious damage to
your vehicle:
Reducing vehicle speed.
Avoiding hard accelerations.
0 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
Fi//ing 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.
If none of the above steps have made the light turn off,
have your dealer or qualified service center check
the vehicle. Your dealer has the proper test equipment
and diagnostic tools to
fix any mechanical or electrical
problems that may have developed.
3-39

Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
may begin programs to inspect the emission control
equipment on your vehicle. Failure to pass this
inspection could prevent you from getting a vehicle
registration.
Here are some things you need to know to help your
vehicle pass an inspection:
Your vehicle will not pass this inspection
if the Check
Engine light is on or not working properly.
Your vehicle will not pass this inspection
if the OBD
(on-board diagnostic) system determines that critical
emission control systems have not been completely
diagnosed by the system. The vehicle would be
considered not ready for inspection. This can happen
if
you have recently replaced your battery or if your
battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This may take several days
of routine driving.
If you have done this and your vehicle
still does not pass the inspection for lack of
OBD
system readiness, see your dealer or qualified service
center to prepare the vehicle for inspection.
Oil Pressure Gage
I I
United States Canada
The oil pressure gage shows the engine oil pressure in
psi (pounds per square inch) when the engine is
running. Canadian vehicles indicate pressure in kPa
(kilopascals).
Oil pressure may vary with engine speed, outside
temperature and oil viscosity, but readings above the
low pressure zone indicate the normal operating range.
3-40

A reading in the low pressure zone may be caused by a
dangerously low oil level or some other problem
causing
low oil pressure. Check your oil as soon as
possible. See
DIC Warnings and Messages on
page 3-53
and ‘vgine Oil on page 5-13.
Don’t keep driving if the oil pressure is low. If
you do, your engine can become
so hot that it
catches fire. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice: Damage to your engine from neglected oil
problems can be costly and is not covered by
your warranty.
Cruise Control Light
The cruise light comes on
whenever you set your
cruise control. See “Cruise
Control” under
Turn
SignaVMultifunction Lever
on page 3-5.
Tow/HauI Mode Light
This light is displayed
when the tow/haul mode
has been activated.
For more information, see
Towing a Trailer on
page 4-5
I.
3-41