2004 CHEVROLET EXPRESS CARGO VAN check engine

Hill and Mountain Roads
Driving on steep hills or mountains is different from
driving in at or rolling terrain.If you drive regularly in steep country, or if you are
planning to visit there, here are some tips that can make
your trips safer and more enjoyable.
Keep your vehicle in good shape. Check all uid
levels and also the brakes, tires, cooling system
and transmission. These parts can work hard
on mountain roads.
Know how to go down hills. The most important
thing to know is this: let your engine do some of
the slowing down. Shift to a lower gear when you go
down a steep or long hill.
{CAUTION:
If you do not shift down, your brakes could get
so hot that they would not work well. You
would then have poor braking or even none
going down a hill. You could crash. Shift down
to let your engine assist your brakes on a
steep downhill slope.
4-25

You can run the engine to keep warm, but be careful.
{CAUTION:
Snow can trap exhaust gases under your
vehicle. This can cause deadly CO (carbon
monoxide) gas to get inside. CO could
overcome you and kill you. You can not see it
or smell it, so you might not know it is in your
vehicle. Clear away snow from around the
base of your vehicle, especially any that is
blocking your exhaust pipe. And check around
again from time to time to be sure snow does
not collect there.
Open a window just a little on the side of the
vehicle that is away from the wind. This will
help keep CO out.
Run your engine only as long as you must. This saves
fuel. When you run the engine, make it go a little
faster than just idle. That is, push the accelerator
slightly. This uses less fuel for the heat that you get and
it keeps the battery (or batteries) charged. You will
need a well-charged battery (or batteries) to restart the
vehicle, and possibly for signaling later on with your
headlamps. Let the heater run for a while.
4-30

Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring and a heavy-duty turn signal asher (included
in the optional trailering package).
The arrows on your instrument panel will ash whenever
you signal a turn or lane change. Properly hooked up,
the trailer lamps will also ash, telling other drivers
you’re about to turn, change lanes or stop.
When towing a trailer, the arrows on your instrument
panel will ash for turns even if the bulbs on the trailer
are burned out. Thus, you may think drivers behind
you are seeing your signal when they are not. It’s
important to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gearbeforeyou start
down a long or steep downgrade. If you don’t shift
down, you might have to use your brakes so much that
they would get hot and no longer work well.
You can tow in DRIVE (D). You may want to shift the
transmission to THIRD (3) or a lower gear under heavy
loads and/or hilly conditions.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a lower
temperature than at normal altitudes. If you turn your
engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating. To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in PARK (P) for a
few minutes before turning the engine off. If you do get
the overheat warning, seeEngine Overheating on
page 5-26.
4-49

Parking on Hills
{CAUTION:
You really should not park your vehicle, with a
trailer attached, on a hill. If something goes
wrong, your rig could start to move. People
can be injured, and both your vehicle and the
trailer can be damaged.
But if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK (P) yet. Then turn your wheels into the curb if
facing downhill or into traffic if facing uphill.
2. Have someone place chocks under the trailer
wheels.
3. When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your
parking brake and then shift to PARK (P).
5. Release the regular brakes.
When You Are Ready to Leave After
Parking on a Hill
1. Apply your regular brakes and hold the pedal down
while you:
start your engine,
shift into a gear, and
release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the
chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission uid (don’t overll),
engine oil, axle lubricant, belt, cooling system and
brake system. Each of these is covered in this manual,
and the Index will help you nd them quickly. If
you’re trailering, it’s a good idea to review these sections
before you start your trip.
Check periodically to see that all hitch nuts and bolts
are tight.
4-50

Service............................................................5-3
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
Your Vehicle..............................................5-4
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-5
California Fuel...............................................5-6
Additives.......................................................5-6
Fuels in Foreign Countries...............................5-7
Filling Your Tank............................................5-8
Filling a Portable Fuel Container.......................5-9
Checking Things Under
the Hood....................................................5-10
Hood Release..............................................5-10
Engine Compartment Overview.......................5-12
Engine Oil...................................................5-13
Engine Air Cleaner/Filter................................5-18
Automatic Transmission Fluid.........................5-19
Engine Coolant.............................................5-22
Radiator Pressure Cap..................................5-25
Engine Overheating.......................................5-26
Cooling System............................................5-28Engine Fan Noise.........................................5-36
Power Steering Fluid.....................................5-36
Windshield Washer Fluid................................5-38
Brakes........................................................5-39
Battery........................................................5-42
Jump Starting...............................................5-43
All-Wheel Drive..............................................5-48
Rear Axle.......................................................5-49
Front Axle......................................................5-50
Noise Control System.....................................5-51
Tampering with Noise Control System
Prohibited.................................................5-51
Bulb Replacement..........................................5-52
Halogen Bulbs..............................................5-52
Headlamps..................................................5-52
Front Turn Signal, Sidemarker and
Parking Lamps..........................................5-54
Taillamps.....................................................5-54
Replacement Bulbs.......................................5-56
Windshield Wiper Blade Replacement..............5-56
Section 5 Service and Appearance Care
5-1

California Fuel
If your vehicle is certied to meet California Emission
Standards (see the underhood emission control label), it
is designed to operate on fuels that meet California
specications. If this fuel is not available in states
adopting California emissions standards, your vehicle
will operate satisfactorily on fuels meeting federal
specications, but emission control system performance
may be affected. The malfunction indicator lamp may
turn on (seeMalfunction Indicator Lamp on page 3-34)
and your vehicle may fail a smog-check test. If this
occurs, return to your authorized GM dealer for
diagnosis. If it is determined that the condition is caused
by the type of fuel used, repairs may not be covered
by your warranty.
Additives
To 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. However, some gasolines contain only the
minimum amount of additive required to meet U.S.
Environmental Protection Agency regulations. General
Motors recommends that you buy gasolines that
are advertised to help keep fuel injectors and intake
valves clean. If your vehicle experiences problems due
to dirty injectors or valves, try a different brand of
gasoline.
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 specications described earlier.
5-6

Checking Things Under
the Hood
{CAUTION:
Things that burn can get on hot engine parts
and start a re. These include liquids like fuel,
oil, coolant, brake uid, windshield washer and
other uids, 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.
Hood Release
To open the hood, do the following:
1. Pull this handle inside
the vehicle. It is located
in front of the driver’s
side door frame
near the oor.
5-10

A. Battery. SeeBattery on page 5-42.
B. Radiator Pressure Cap. SeeRadiator Pressure Cap
on page 5-25.
C. Coolant Recovery Tank. SeeCooling System on
page 5-28.
D. Transmission Fluid Dipstick. SeeAutomatic
Transmission Fluid on page 5-19.
E. Engine Oil Fill. SeeEngine Oil on page 5-13.
F. Engine Oil Dipstick. SeeEngine Oil on page 5-13.
G. Air Filter Restriction Indicator. SeeEngine Air
Cleaner/Filter on page 5-18.
H. Engine Air Cleaner/Filter. SeeEngine Air
Cleaner/Filter on page 5-18.
I. Power Steering Reservoir. SeePower Steering Fluid
on page 5-36.
J. Brake Master Cylinder. SeeBrakes on page 5-39.
K. Windshield Washer Fluid. SeeWindshield Washer
Fluid on page 5-38.Engine Oil
Checking Engine Oil
It is 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 handle is a yellow loop. See
Engine Compartment Overview on page 5-12for
the location of the engine oil dipstick.
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.
5-13