2002 GMC YUKON XL check engine

6-5To provide cleaner air, all gasolines in the United States
are now required to contain additives that will help
prevent engine and fuel system deposits from forming,
allowing your emission control system to work properly.
You should not have to add anything to your fuel.
Gasolines containing oxygenates, such as ethers and
ethanol, and reformulated gasolines may be available in
your area to contribute to clean air. General Motors
recommends that you use these gasolines, particularly if
they comply with the specifications described earlier.
NOTICE: Your vehicle was not designed for fuel that
contains methanol. Don't use fuel containing
methanol. It can corrode metal parts in your
fuel system and also damage plastic and rubber
parts. That damage wouldn't be covered under
your warranty. Fuels in Foreign Countries If you plan on driving in another country outside the
United States or Canada, the proper fuel may be hard to
find. Never use leaded gasoline or any other fuel not
recommended in the previous text on fuel. Costly repairs
caused by use of improper fuel wouldn't be covered by
your warranty.
To check on fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you'll be driving.

6-8Filling a Portable Fuel Container
CAUTION:Never fill a portable fuel container while it is in
your vehicle. Static electricity discharge from the
container can ignite the gasoline vapor. You can
be badly burned and your vehicle damaged if this
occurs. To help avoid injury to you and others:

Dispense gasoline only into
approved containers.

Do not fill a container while it is inside a
vehicle, in a vehicle's trunk, pickup bed or
on any surface other than the ground.

Bring the fill nozzle in contact with the
inside of the fill opening before operating
the nozzle. Contact should be maintained
until the filling is complete.

Don't smoke while pumping gasoline. Checking Things Under the Hood
CAUTION: Things that burn can get on hot engine parts and
start a fire. These include liquids like fuel, oil,
coolant, brake fluid, windshield washer and other
fluids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.

6-11A. Engine Air Cleaner/Filter
B. Coolant Surge Tank
C. Air Filter Restriction Indicator
D. Engine Oil 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 ENG OIL
LEVEL message appears
on the instrument cluster,
it means you need to check
your engine oil level
right away.
For more information, see ªCHECK ENG OIL LEVELº
in the Index.
You should check your engine oil level regularly; this is
an added reminder.

6-12Checking 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 is a
loop handle and is located
in the engine compartment
on the passenger's side of
the vehicle. See ªEngine
Compartment Overviewº in
the Index 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.

6-15As in the chart shown previously, SAE 5W
- 30 is best for
your vehicle. However, you can use SAE 10W
- 30 if it's
going to be 0  F (
- 18  C) or above. These numbers on an
oil container show its viscosity, or thickness. Do not use
other viscosity oils, such as SAE 20W
- 50.
NOTICE: Use only engine oil with the American Petroleum
Institute Certified For Gasoline Engines
starburst symbol. Failure to use the
recommended oil can result in engine damage not
covered by your warranty.
GM Goodwrench

oil meets all the requirements for
your vehicle.
If you are in an area where the temperature falls below
- 20  F (
- 29  C), consider using either an SAE 5W
- 30
synthetic oil or an SAE 0W
- 30 oil. Both will provide
easier cold starting and better protection for your engine
at extremely low temperatures.
Engine Oil Additives
Don't add anything to your oil. The recommended oils
with the starburst symbol are all you will need for good
performance and engine protection. When to Change Engine Oil
(GM Oil Life System  )Your vehicle has a computer system that lets you know
when to change the engine oil and filter. This is based on
engine revolutions and engine temperature, and not on
mileage. Based on driving conditions, the mileage at
which an oil change will be indicated can vary
considerably. For the oil life system to work properly,
you must reset the system every time the oil is changed.
When the system has calculated that oil life has been
diminished, it will indicate that an oil change is
necessary. A CHANGE ENGINE OIL message will
come on. Change your oil as soon as possible within the
next two times you stop for fuel. It is possible that, if
you are driving under the best conditions, the oil life
system may not indicate that an oil change is necessary
for over a year. However, your engine oil and filter must
be changed at least once a year and at this time the
system must be reset. It is also important to check your
oil regularly and keep it at the proper level.
If the system is ever reset accidentally, you must change
your oil at 3,000 miles (5 000 km) since your last oil
change. Remember to reset the oil life system whenever
the oil is changed.

6-17Engine Air Cleaner/Filter The engine air cleaner/filter 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 ªEngine Compartment Overviewº
in the Index for more information on location.
See ªOwner Checks and Servicesº in the Index to
determine when to check the air filter restriction indicator.
The service window (A)
with the percentage scale
shows the amount of engine
air cleaner/filter life used.
When both service window (A) and service window (B)
turn orange, replace the engine air cleaner/filter.
After changing the engine air cleaner/filter, press the
button on top of the air filter restriction indicator to reset it. Your engine air cleaner/filter is located in the air filter
housing near the front corner of the engine compartment
on the passenger's side of the vehicle. See ªEngine
Compartment Overviewº in the Index for more
information on location.

6-18 1. To remove the engine air cleaner/filter, loosen the
screws on the cover.
2. Lift the cover upward and remove the engine air
cleaner/filter out of the air cleaner housing. Care
should be taken to dislodge as little dirt as possible.
3. Clean the filter sealing surface and the housing.
4. Install the new engine air cleaner/filter.
5. Install the cover and tighten the screws. Refer to the Maintenance Schedule to determine when to
replace the engine air cleaner/filter. See ªOwner Checks
and Servicesº in the Index.
CAUTION: Operating the engine with the air cleaner/filter
off can cause you or others to be burned. The air
cleaner not only cleans the air, it stops flame if
the engine backfires. If it isn't there, and the
engine backfires, you could be burned. Don't
drive with it off, and be careful working on the
engine with the air cleaner/filter off.
NOTICE: If the air cleaner/filter is off, a backfire can
cause a damaging engine fire. And, dirt can easily
get into your engine, which will damage it.
Always have the air cleaner/filter in place when
you're driving.

6-20Automatic Transmission Fluid When to Check and Change A good time to check your automatic transmission fluid
level is when the engine oil is changed.
Change both the fluid and filter every 50,000 miles
(83 000 km) if the vehicle is mainly driven under one or
more of these conditions:

In heavy city traffic where the outside temperature
regularly reaches 90  F (32  C) or higher.

In hilly or mountainous terrain.

When doing frequent trailer towing.

Uses such as found in taxi, police or delivery service.
If you do not use your vehicle under any of
these conditions, change the fluid and filter
every 100,000 miles (166 000 km).
See ªScheduled Maintenance Servicesº in the Index. How to Check Because this operation can be a little difficult, you
may choose to have this done at the dealership
service department.
If you do it yourself, be sure to follow all the
instructions here, or you could get a false reading
on the dipstick.
NOTICE: Too much or too little fluid can damage your
transmission. Too much can mean that some of
the fluid could come out and fall on hot engine
parts or exhaust system parts, starting a fire.
Too little fluid could cause the transmission to
overheat. Be sure to get an accurate reading if
you check your transmission fluid.