2002 GMC YUKON XL engine

2-80Low Coolant This message is displayed
when the cooling system is
low on coolant.
The engine may overheat. See ªEngine Coolantº in
the Index and have your vehicle serviced as soon as
you can.
Check Coolant Temp This message is displayed
when the cooling system
temperature gets hot.
Check the coolant temperature gage and the coolant
level. See ªEngine Coolant,º ªEngine Coolant
Temperature Gageº and ªEngine Overheatingº in the
Index for further information. Engine Overheated This message is displayed
when the cooling system
temperature gets too hot.
This message will be displayed after the air conditioning
system has automatically turned off for the engine
coolant protection mode. See ªEngine Overheatingº in
the Index for further information.
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.
See ªEngine Overheatingº in the Index for
further information.

2-81Check Eng Oil Pressure This message is displayed
when the engine oil pressure
is low.
See ªOil Pressure Gageº in the Index for
more information. Check Eng Oil Level This message is displayed
when the engine oil level
is low.
Once oil is added, it may need time to drain and settle in
the engine before this message will turn off. It is best to
let the engine cool down (if it is hot) or warm up (if it is
cold) and cycle the ignition to be sure this message turns
off. Refer to the dipstick for the correct level.
See ªEngine Oilº in the Index on how to check the oil
level and for what type of oil to add.

2-82Change Engine Oil This message is displayed
when the engine oil needs
to be changed. The message
is only displayed for
15 seconds at the start of
each ignition cycle.
When you change the engine oil, be sure to reset the
Engine Oil Life Monitor. See ªEngine Oil, When to
Changeº in the Index.
Security This message is displayed
when the content
theft
- deterrent system
has been activated and
also monitors the
Passlock

system.
If the security message is displayed continuously while
driving and stays on, there may be a problem with the
Passlock system. Your vehicle will not be protected by
Passlock, and you should see your GM dealer. Low Washer Fluid This message is displayed
when the vehicle is low on
windshield washer fluid.
The message is only
displayed for 15 seconds
each ignition cycle.
For more information, see ªWindshield Washer Fluidº in
the Index.
Service Ride Control This message is
displayed when a possible
problem exists with the
Autoride  system.
For more information, see ªAutoride  º in the Index.

2-84Fuel
Each press of the FUEL button will change the
display between the fuel remaining range, average
fuel economy, instantaneous fuel economy and a
blank display.

The average fuel economy can be reset using the
RESET button.
Trip Each press of the TRIP button will change the
display between personal trip computer, business trip
computer, timer, vehicle history, annual mileage and a
blank display.
Personal Trip Computer and Business
Trip Computer

Each press of the arrow button will change the
display between turn on/off, trip odometer, fuel used,
average fuel economy and average speed.

The ON/OFF button will turn the trip computer on
and off. The information on the trip computer only
gets updated when it is turned on. The personal and
business computers are independent, i.e. turning one
of them on does not turn the other off.
All information associated with the trip computer
will be reset when the RESET button is pressed.

If the RESET button is pressed and held for more
than two seconds, all of the trip computer settings
will reset starting from the last ignition cycle
(turning the ignition from OFF to RUN). This
feature is for someone who has forgotten to reset the
trip computer when pulling out of the driveway and
does not realize it until after driving for awhile.
Timer

Each press of the ON/OFF button will turn the timer
on or off.

The RESET button will reset the timer to 00:00:00.

If turned on, the timer will accumulate whenever
the SIC is powered (the engine does not have to
be running).

The timer will rollover after 99:59:59.

3-5Mode Knob
- Automatic Operation
When the system is set in AUTO mode, sensors will
control the air delivery mode. Air will come primarily
from the floor or instrument panel outlets, with some air
directed to the windshield to prevent fogging.
When the system is in AUTO mode, the air conditioning
light will turn on, and the recirculation and outside air
lights will turn off. With the system in full automatic
control (both the fan and mode knobs in AUTO), you
still have the ability to override any function. However,
continually overriding the outside air or the A/C
compressor will limit the ability of the system to cool
the vehicle quickly.
If you push a button for a function which is not
available, the light next to that button will flash three
times to alert you that it's not available.
To find your comfort zone, start with the 74
F (23
C)
setting and allow about 20 minutes for the system to
adjust the temperature if necessary. With the automatic setting, the air conditioning
compressor automatically cycles when needed to cool
the air. In cold weather, when the system senses the
need for heat, the airflow will be directed out the floor
outlets. As the interior temperature approaches a desired
setting, the fan speed will decrease. To maintain interior
comfort, the airflow will adjust between the instrument
panel outlets and floor outlets. On bright sunny days
in cool weather, the airflow may come out of the
instrument panel and the floor outlets (bi
- level mode)
to maintain comfort and prevent stuffiness.
To avoid blowing cold air in cold weather, the system
will delay turning on the fan until warm air is available.
The length of delay depends on the outside air
temperature, engine coolant temperature or the time
since the engine was last started. As the coolant
warms up, the fan speed will gradually increase and
air will flow from the floor outlets, with some airflow
to the windshield to prevent fogging under most
normal conditions.
Be careful not to put anything over the solar sensor
located near the center of the instrument panel.
This sensor is used by the automatic system to
regulate temperature.

3-8Air Conditioning On hot days, open the windows long enough to let hot
air inside escape. This reduces the time it takes for your
vehicle to cool down. Then keep your windows closed
for the air conditioner to work its best.
The A/C button, located below the mode knob, allows
the air coming into your vehicle to be cooled. This
setting is useful for normal cooling on hot days.
Use A/C with recirculation on to allow the air inside
your vehicle to be recirculated. This setting will help to
maximize your air conditioner's performance and your
vehicle's fuel economy. This setting also cools the air
the fastest and can be used to keep unwanted odors
and/or dust from entering the vehicle.
When using the air conditioner, turn off the recirculation
setting and use the outside air setting after the vehicle
reaches a comfortable interior temperature. When the
right knob on the control panel is between floor and
defrost, the recirculation feature will not function.
This helps reduce window fogging. Passenger Compartment Air Filter
Your vehicle is equipped with a passenger compartment
air filter which filters outside air entering the vehicle.
For information on replacing the filter see ªPassenger
Compartment Air Filterº in the Index.
Heating The heater works best if you keep your windows closed
while using it. On cold days, use the floor or bi
- level
(mode knob set between vent and floor) setting with the
temperature knob in the red area.
On cold days, approximately 32
F (
- 0
C) or lower,
you may experience differences in how the transmission
shifts until the engine is warm. This feature
automatically reduces the time it takes for the engine to
reach normal operating temperature and shortens the
time it takes the heater to reach full output.
If you use the engine coolant heater before starting your
engine in cold weather, 20
F (
- 8
C) or lower, the
heating system will produce warmer air faster to heat the
passenger compartment.
The use of an engine coolant heater also reduces the
time it takes for the engine to reach normal operating
temperature. For more information, see ªEngine Coolant
Heaterº in the Index.

3-11Ventilation Tips

Keep the hood and front air inlet free of ice, snow or
any other obstruction (such as leaves). The heater
and defroster will work far better, reducing the
chance of fogging the inside of your windows.

When you enter a vehicle in cold weather, turn the
fan knob all the way to the right for a few moments
before driving. This helps clear the intake ducts of
snow and moisture, and reduces the chance of
fogging the inside of your windows.

Keep the air path under the front seats clear of
objects. This helps air to circulate throughout
your vehicle.

The use of non
- GM approved hood air deflectors
may adversely affect the performance of the heating
and air conditioning system. Audio Systems Your audio system has been designed to operate easily
and give years of listening pleasure. You will get the
most enjoyment out of it if you acquaint yourself with it
first. 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 has a feature called Retained Accessory
Power (RAP). With RAP, you can play your audio
system even after the ignition is turned off. See
ªRetained Accessory Powerº in the Index.
Setting the Clock Press and hold HR until the correct hour appears on the
display. Press and hold MN until the correct minute
appears on the display. To display the clock with the
ignition off, press RECALL or HR/MN and the time
will be displayed for a few seconds. There is an initial
two
- second delay before the clock goes into the
time
- set mode.

3-25Understanding Radio Reception AM
The range for most AM stations is greater than for FM,
especially at night. The longer range, however, can
cause stations to interfere with each other. AM can pick
up noise from things like storms and power lines. Try
reducing the treble to reduce this noise if you ever get it.
FM Stereo
FM stereo will give you the best sound, but FM signals
will reach only about 10 to 40 miles (16 to 65 km). Tall
buildings or hills can interfere with FM signals, causing
the sound to come and go.
Tips About Your Audio System Hearing damage from loud noise is almost undetectable
until it is too late. Your hearing can adapt to higher
volumes of sound. Sound that seems normal can be loud
and harmful to your hearing. Take precautions by
adjusting the volume control on your radio to a safe
sound level before your hearing adapts to it. To help avoid hearing loss or damage do the following:
1. Adjust the volume control to the lowest setting.
2. Increase volume slowly until you hear comfortably
and clearly.
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, Delphi Electronics 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.