2008 HUMMER H3 check engine

Malfunction Indicator Lamp
Check Engine Light
A computer system called OBD II (On-Board
Diagnostics-Second Generation) monitors operation of
the fuel, ignition, and emission control systems. It makes
sure 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 an OBD II
problem and service
is required.
Malfunctions often are indicated by the system before
any problem is apparent. This can 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, the emission controls might
not work as well, your vehicle’s fuel economy might
not be as good, and the engine might not run as
smoothly. This could lead to costly repairs that might
not be covered by your warranty.Notice:Modications 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 can cause this light to come on.
Modications to these systems could lead to costly
repairs not covered by your warranty. This could
also result in a failure to pass a required Emission
Inspection/Maintenance test. SeeAccessories
and Modifications on page 5-3.
This light comes on, as a check to show it is working,
when the ignition is turned ON/RUN but the engine is not
running. If the light does not come on, have it repaired.
This light also comes on during a malfunction in
one of two ways:
Light Flashing— A misre condition has been
detected. A misre increases vehicle emissions
and could damage the emission control system on
your vehicle. Diagnosis and service might be
required.
Light On Steady— An emission control system
malfunction has been detected on your vehicle.
Diagnosis and service might be required.
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If the Light is Flashing
The following can prevent more serious damage to your
vehicle:
Reduce vehicle speed.
Avoid hard accelerations.
Avoid 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 ashing and remains on steady, see “If
the Light Is On Steady” following.
If the light continues to ash, when it is safe to do so,
stop the vehicle. Find a safe place to park the vehicle.
Turn the ignition 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 ashing,
follow the previous steps and see your dealer/retailer
for service as soon as possible.
If the Light Is On Steady
You might 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. SeeFilling the Tank on page 5-8. The
diagnostic system can determine if the fuel cap hasbeen left off or improperly installed. A loose or missing
fuel cap allows 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 vehicle’s electrical system might be wet.
The condition is usually 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 causes
the engine not to run as efficiently as designed. You
might notice this as stalling after start-up, stalling when
you put the vehicle into gear, misring, hesitation on
acceleration, or stumbling on acceleration — these
conditions might 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,
your dealer/retailer can check the vehicle. Your
dealer/retailer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that might have developed.
3-37

Emissions Inspection and Maintenance
Programs
Some state/provincial and local governments have or
might 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 the battery or if the
battery has run down. The diagnostic system is
designed to evaluate critical emission control systems
during normal driving. This can 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, your dealer/retailer can prepare the
vehicle for inspection.
Oil Pressure Light
{CAUTION:
Do not keep driving if the oil pressure is low. If
you do, your engine can become so hot that it
catches re. You or others could be burned.
Check your oil as soon as possible and have
your vehicle serviced.
Notice:Lack of proper engine oil maintenance may
damage the engine. The repairs would not be covered
by your warranty. Always follow the maintenance
schedule in this manual for changing engine oil.
This light will come on
briey when you start your
engine. If it does not,
have your vehicle serviced.
When the light comes on and stays on, it means that oil
is not owing through your engine properly. You
could be low on oil and you might have some other
system problem.
3-38

AC (Air Conditioning) OFF
This message displays when the engine coolant
temperature is too high and the air conditioning in your
vehicle needs to be turned off. SeeEngine Overheating
on page 5-29andClimate Control System on
page 3-22for more information. This message displays
along with the ENG HOT message.
ABS (Antilock Brake System) FAULT
This message displays if there is a problem with
the Antilock Brake System (ABS). Check the ABS as
soon as possible and have your vehicle serviced by your
dealer/retailer. SeeBrakes on page 5-38andAntilock
Brake System Warning Light on page 3-34for more
information. Press and release the reset stem to
acknowledge the message and clear it from the display.
BRAKES
This message displays if there is a problem with the
brakes. Check the brakes as soon as possible and have
your vehicle serviced by your dealer/retailer. See
Brakes on page 5-38andBrake System Warning Light
on page 3-33for more information. Press and release
the reset stem to acknowledge the message and clear it
from the display.
CHANGE OIL
This message displays when the oil needs to be
changed. Check the oil in your vehicle as soon as
possible and have your vehicle serviced by your
dealer/retailer. SeeEngine Oil on page 5-15and
Scheduled Maintenance on page 6-4for more
information. Press and release the reset stem to
acknowledge the message and clear it from the display.
DOORS
This message displays when one or more of the doors
is ajar. Check all the doors on your vehicle to make
sure they are closed. The message clears from
the display after all of the doors are closed.
ENG (Engine) HOT
This message displays when the engine coolant
temperature is hot. Check the engine coolant
temperature gage. SeeEngine Coolant Temperature
Gage on page 3-35. Have your vehicle serviced by your
dealer/retailer as soon as possible if you suspect the
engine is overheating. SeeEngine Overheating on
page 5-29for more information.
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FLUID
This message displays if the brake uid is low. Check
the brake uid as soon as possible and have your
vehicle serviced by your dealer/retailer. SeeBrakes on
page 5-38for more information. Press and release
the reset stem to acknowledge the message and clear it
from the display.
FUEL CAP
This message displays if the vehicle’s fuel cap is either
off or loose. Pull over as soon as possible and check
to see if the fuel cap is secure. You may also see
the check engine light on the instrument panel cluster.
If the check engine light does come on when the
fuel cap was loose, it may take a few driving trips before
the light turns off. SeeMalfunction Indicator Lamp on
page 3-36for more information if the light still remains
on. Press and release the reset stem to acknowledge
the message and clear it from the display.
LOW FUEL
This message displays if the level of fuel in the vehicle
is low. Also check the fuel gage. SeeFuel Gage on
page 3-40for more information. Rell the fuel tank as
soon as possible.
LOW TIRE
This message displays if a low tire pressure is detected
in any of the vehicle’s tires. Press and release the reset
stem to acknowledge the message and clear it from the
display. The message appears at each ignition cycle until
the tires are inated to the correct ination pressure. See
Tires on page 5-54andInflation - Tire Pressure on
page 5-62for more information on tires and the correct
ination pressures.
OIL
This message displays when the oil pressure is low.
SeeOil Pressure Light on page 3-38andEngine Oil
on page 5-15for more information.
PARK BRK (Brake)
This message displays when the parking brake is set.
SeeParking Brake on page 2-32andBrake System
Warning Light on page 3-33for more information. The
message clears from the display after the parking brake
is released or by pressing and releasing the reset stem.
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REDUCED POWER
This message displays when the vehicle’s engine power
is reduced. Reduced engine power can affect the
vehicle’s ability to accelerate. If this message is on, but
there is no reduction in performance, proceed to
your destination. The performance may be reduced the
next time the vehicle is driven. The vehicle may be
driven at a reduced speed while this message is on, but
acceleration and speed may be reduced. Anytime this
message stays on, the vehicle should be taken to
your dealer/retailer for service as soon as possible.
Press and release the reset stem to acknowledge the
message and clear it from the display.
SERV (Service) 4WD (Four-Wheel
Drive)
This message displays when there is a problem with the
transfer case control system. Check the transfer case
on your vehicle and have it serviced by your
dealer/retailer. SeeFull-Time Four-Wheel Drive on
page 2-27for more information about the transfer case.
Press and release the reset stem to acknowledge
the message and clear it from the display.
SERV (Service) TPM (Tire Pressure
Monitor)
This message displays if a part on the Tire Pressure
Monitor System (TPMS) is not working properly. The tire
pressure light also ashes and then remains on during
the same ignition cycle. SeeTire Pressure Light on
page 3-35. Several conditions may cause this message
to appear. SeeTire Pressure Monitor Operation on
page 5-65for more information. If the warning comes on
and stays on, there may be a problem with the TPMS.
See your dealer/retailer.
SERV (Service) VEH (Vehicle)
This message displays if your vehicle needs service.
Have your vehicle serviced by your dealer/retailer
as soon as possible.
3-46

Audio System(s)
Determine which radio your vehicle has and then read
the pages following to familiarize yourself with its
features.
{CAUTION:
This system provides you with far greater
access to audio stations and song listings.
Giving extended attention to entertainment
tasks while driving can cause a crash and you
or others can be injured or killed. Always keep
your eyes on the road and your mind on the
drive — avoid engaging in extended searching
while driving.
Keeping your mind on the drive is important for safe
driving. SeeDefensive Driving on page 4-2. Here
are some ways in which you can help avoid distraction
while driving.
While your vehicle is parked:
Familiarize yourself with all of its controls.
Familiarize yourself with its operation.
Set up your audio system by presetting your
favorite radio stations, setting the tone, and
adjusting the speakers. Then, when driving
conditions permit, you can tune to your favorite
radio stations using the presets and steering wheel
controls if the vehicle has them.
Notice:Before adding any sound equipment to
your vehicle, such as an audio system, CD player,
CB radio, mobile telephone, or two-way radio, make
sure that it can be added by checking with your
dealer/retailer. Also, check federal rules covering
mobile radio and telephone units. If sound
equipment can be added, it is 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.
Your vehicle has a feature called Retained Accessory
Power (RAP). With RAP, the audio system can be
played even after the ignition is turned off. SeeRetained
Accessory Power (RAP) on page 2-20for more
information.
Setting the Time
Press and hold H until the correct hour and AM or PM
displays. Press and hold M until the correct minute
displays. The time can be set with the ignition on or off.
3-48

This is a mistake. The brakes might not have time to
cool between hard stops. The brakes will wear out
much faster if you do a lot of heavy braking. If you
keep pace 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 vehicle ever loses electrical power while you
are driving, brake normally but do not pump the brakes.
If you do, the pedal could get harder to push down.
If your vehicle loses electrical power, you will still have
some power brake assist. But you will use it when
you brake. Once the power assist is used up, it can take
longer to stop, the brake pedal will be harder to push,
and you might experience longer pedal travel.
Adding non-dealer/non-retailer accessories can affect
your vehicle’s performance. SeeAccessories and
Modifications on page 5-3.Antilock Brake System (ABS)
Your vehicle has the Antilock Brake System (ABS),
an advanced electronic braking system that will
help prevent a braking skid.
When you start the engine and begin to drive away,
ABS will check itself. You might hear a momentary
motor or clicking noise while this test is going on.
This is normal.
If there is a problem with
ABS, this warning light will
stay on. SeeAntilock
Brake System Warning
Light on page 3-34.
Let us say the road is wet and you are driving safely.
Suddenly, an animal jumps out in front of you. You slam
on the brakes and continue braking. Here is what
happens with ABS:
A computer senses that wheels are slowing down.
If one of the wheels is about to stop rolling, the computer
will separately work the brakes at each wheel.
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