check engine light GMC YUKON 2007 Owner's Manual

This device complies with RSS-210 of Industry
Canada. Operation is subject to the following
two conditions:
1. This device may not cause interference.
2. This device must accept any interference
received, including interference that may
cause undesired operation of the device.
Changes or modications to this system by other
than an authorized service facility could void
authorization to use this equipment.
PASS-Key
®III+ uses a radio frequency
transponder in the key that matches a decoder
in your vehicle.
PASS-Key®III+ Operation
Your vehicle has PASS-Key®III+ (Personalized
Automotive Security System) theft-deterrent
system. PASS-Key
®III+ is a passive
theft-deterrent system. This means you do not
have to do anything special to arm or disarm the
system. It works when you transition the key
to RUN, ACCESSORY or START from the
OFF position.When the PASS-Key
®III+ system senses that
someone is using the wrong key, it prevents the
vehicle from starting. Anyone using a trial-and-error
method to start the vehicle will be discouraged
because of the high number of electrical key codes.
If the engine does not start and the security light
on the instrument panel comes on when trying
to start the vehicle, the key may have a damaged
transponder. Turn the ignition off and try again.
If the engine still does not start, and the key
appears to be undamaged, try another ignition
key. At this time, you may also want to check
the fuse, seeFuses and Circuit Breakers on
page 538. If the engine still does not start with the
other key, your vehicle needs service. If your
vehicle does start, the rst key may be faulty. See
your dealer who can service the PASS-Key
®III+
to have a new key made. In an emergency,
contact Roadside Assistance.
137

Warning Lights, Gages, and
Indicators
This part describes the warning lights and gages
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 briey when
you start the engine just to let you know they
are 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 is 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 are a big help.
Your vehicle also has a Driver Information Center
(DIC) that works along with warning lights and
gages. SeeDIC Warnings and Messages
on page 252.
225

Charging System Light
The charging system
light will come on briey
when you turn on the
ignition, but the
engine is not running,
as a check to show you
it is working.
It should go out once the engine is running. If it
stays on, or comes on while you are driving,
you may have a problem with the charging system.
It could indicate that you have problems with a
generator drive belt, or another electrical problem.
Have it checked right away. Driving while this
light is on could drain your battery.
When this light comes on the DIC will also display
the battery not charging message. SeeDIC
Warnings and Messages on page 252.
If you must drive a short distance with the light on,
be certain to turn off all your accessories, such
as the radio and air conditioner.
Voltmeter Gage
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. The gage
may transition from a higher to lower or a lower to
higher reading, this is normal. Readings between
the low and high warning zones indicate the
normal operating range.
232

Engine Coolant Temperature Gage
This gage shows the engine coolant temperature.
It also provides an indicator of how hard your
vehicle is working. During a majority of the
operation, the gage will read 210°F (100°C) or
less. If you are pulling a load or going up hills,
it is normal for the temperature to uctuate
and approach the 250°F (122°C) mark. If the gage
reaches the 260°F (125°C) mark, it indicates
that the cooling system is working beyond
its capacity.
SeeEngine Overheating on page 448.
Tire Pressure Light
If your vehicle is
equipped with the Tire
Pressure Monitor
system, this light will
come on if the system
detects low tire
pressure.
A CHECK TIRE PRESSURE DIC message will
accompany the light.
This light will also come on briey as you start the
engine.
SeeTire Pressure Monitor System on page 490
for more information.
For more information on your tires, seeTires on
page 480.
United StatesCanada
236

Malfunction Indicator Lamp
Check Engine Light
Your vehicle has a
computer which
monitors operation of
the fuel, ignition,
and emission control
systems.
This system is called OBD II (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 awhile, 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: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 may
cause this light to come on. Modications 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. SeeAccessories
and Modifications on page 421.
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 does not
come on, have it repaired.
237

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.
SeeGasoline Octane on page 423. 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, misring, 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, your dealer can check the vehicle.
Your dealer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that may have developed.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, your GM dealer
can prepare the vehicle for inspection.
239

Oil Pressure Light
This light will come on
briey when you start
your engine.
{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.
That is a check to be sure the light works. If it
does not come on, be sure to have it xed so it will
be there to warn you if something goes wrong.
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.Security Light
This light will come on
briey when you turn
the key toward START.
The light will stay on
until the engine starts.
SeePASS-Key
®III+ Operation on page 137for
more information.
241

CHANGE ENGINE OIL SOON
This message will display when the engine oil
needs to be changed. When you change the
engine oil, be sure to reset the CHANGE ENGINE
OIL SOON message. SeeEngine Oil Life
System on page 435for information on how to
reset the message. This message will clear itself
after 10 seconds until the next ignition cycle
or until the message is reset. SeeEngine Oil
on page 432andScheduled Maintenance
on page 551for more information.
CHECK TIRE PRESSURE
If your vehicle has a Tire Pressure Monitor (TPM)
system, this message will display when the
pressure in one or more of the vehicle’s tires need
to be checked. This message will also display
LEFT FRONT, RIGHT FRONT, LEFT REAR, or
RIGHT REAR to indicate which tire needs to
be checked. You can receive more than one tire
pressure message at a time. To read the other
messages that may have been sent at the same
time, press the set/reset button or the trip
odometer reset stem.If a tire pressure message appears on the DIC,
stop as soon as you can. Have the tire pressures
checked and set to those shown on your Tire
Loading Information Label. SeeTires on page 480,
Loading Your Vehicle on page 392, and
Ination - Tire Pressure on page 488. The DIC
display also shows the tire pressure values for the
front and rear tires by pressing the vehicle
information button. See “DIC Operation and
Displays (Using DIC Buttons)” earlier in this
section. If the tire pressure is low, the low tire
pressure warning
light will come on. SeeTire Pressure Light on
page 236.DRIVER DOOR OPEN
If the driver’s door is not fully closed and the
vehicle is in a drive gear, this message will display
and a chime will sound. Stop and turn off the
vehicle, check the door for obstructions, and close
the door again. Check to see if the message
still appears on the DIC.
253

There are several 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. See
Brake System Warning Light on page 233.
The message could be displayed if the stability
system takes longer than usual to complete its
diagnostic checks due to driving conditions.
If an engine or vehicle related problem has
been detected and the vehicle needs
service, the message will appear. See your
dealer.
The message will also appear if the vehicle is
shifted into 4LO.
The message will turn off as soon as the
conditions that caused the message to be
displayed are no longer present.
TIGHTEN GAS CAP
If the vehicle’s fuel cap is not tightened properly,
this message may display along with the check
engine light on the instrument panel cluster.
SeeMalfunction Indicator Lamp on page 237.
Reinstall the fuel cap fully. SeeFilling the Tank on
page 426. 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 this
light and message off.
TIRE LEARNING ACTIVE
If your vehicle has a Tire Pressure Monitor (TPM)
system, this message will display when the
system is re-learning the tire positions on your
vehicle. See “DIC Operation and Displays (Using
DIC Buttons)” earlier in this section for more
information. The tire positions must be re-learned
after rotating the tires or after replacing a tire
or sensor. SeeTire Inspection and Rotation on
page 496,Tire Pressure Monitor System on
page 490, andInation - Tire Pressure on
page 488for more information.
260

Avoid needless heavy braking. Some people drive
in spurts — heavy acceleration followed by
heavy braking — rather than keeping pace with
traffic. This is a mistake. Your brakes may
not have time to cool between hard stops. Your
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 engine ever stops while you are driving,
brake normally but do not 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.
Adding non-GM accessories can affect your
vehicle’s performance. SeeAccessories and
Modications on page 421.Anti-Lock Brake System (ABS)
Your vehicle has the Anti-Lock Brake System
(ABS), an advanced electronic braking system that
will help prevent a braking skid.
When you start your engine and begin to drive
away, ABS will check itself. You may 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.
SeeAnti-Lock Brake
System Warning
Light on page 234.
Along with ABS, your vehicle has a Dynamic Rear
Proportioning (DRP) system. If there is 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.
347