2002 GMC SONOMA fuel cap

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If the Light Is On Steady
You may 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. See ªFilling Your Tankº in the Index. 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 the light off.
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. See
ªFuelº in the Index. 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, misfiring, 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,
have your dealer or qualified service center check the
vehicle. Your dealer has the proper test equipment and
diagnostic tools to fix any mechanical or electrical
problems that may have developed.

2-82 Fuel Gage
United States Canada
When the ignition is on, the fuel gage tells you about
how much fuel you have remaining.Here are four things that some owners ask about. None
of these show a problem with your fuel gage:

At the gas station, the gas pump shuts off before the
gage reads full.

It takes a little more or less fuel to fill up than the
gage indicated. For example, the gage may have
indicated the tank was half full, but it actually took a
little more or less than half the tank's capacity to fill
the tank.

The gage moves a little when you turn a corner or
speed up.

The gage doesn't go back to empty when you turn
off the ignition.

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Then, shut the engine off and close the window almost
all the way to preserve the heat. Start the engine again
and repeat this only when you feel really uncomfortable
from the cold. But do it as little as possible. Preserve the
fuel as long as you can. To help keep warm, you can get
out of the vehicle and do some fairly vigorous exercises
every half hour or so until help comes.
Recreational Vehicle Towing
Recreational vehicle towing means towing your vehicle
behind another vehicle
-- such as behind a motorhome.
The two most common types of recreational vehicle
towing are known as ªdinghy towingº (towing your
vehicle with all four wheels on the ground) and ªdolly
towingº (towing your vehicle with two wheels on the
ground and two wheels up on a device known as
a ªdollyº).
With the proper preparation and equipment, many
vehicles can be towed in these ways. See ªDinghy
Towingº and ªDolly Towing,º following.Here are some important things to consider before you
do recreational vehicle towing:

What's the towing capacity of the towing vehicle?
Be sure you read the tow vehicle manufacturer's
recommendations.

How far will you tow? Some vehicles have
restrictions on how far and how long they can tow.

Do you have the proper towing equipment? See your
dealer or trailering professional for additional advice
and equipment recommendations.

Is your vehicle ready to be towed? Just as you would
prepare your vehicle for a long trip, you'll want to
make sure your vehicle is prepared to be towed. See
ªBefore Leaving on a Long Tripº in the Index.

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Loading Your Vehicle
The Certification/Tire label is found on the driver's door
edge, above the door latch. The label shows the size of
your original tires and the inflation pressures needed to
obtain the gross weight capacity of your vehicle. This is
called the Gross Vehicle Weight Rating (GVWR). The
GVWR includes the weight of the vehicle, all occupants,
fuel, cargo and trailer tongue weight, if pulling a trailer.The Certification/Tire label also tells you the maximum
weights for the front and rear axles, called Gross Axle
Weight Rating (GAWR). To find out the actual loads on
your front and rear axles, you need to go to a weigh
station and weigh your vehicle. Your dealer can help
you with this. Be sure to spread out your load equally on
both sides of the centerline.
Never exceed the GVWR for your vehicle, or the
GAWR for either the front or rear axle.
And, if you do have a heavy load, you should spread
it out.
Similar appearing vehicles may have different GVWRs
and payloads. Please note the Certification/Tire label on
your truck or consult your dealer for additional details.CAUTION:
In the case of a sudden stop or collision, things
carried in the bed of your truck could shift
forward and come into the passenger area,
injuring you and others. If you put things in the
bed of your truck, you should make sure they are
properly secured.

4-47 Payload
The payload capacity is shown on the Certification/Tire
label. This is the maximum load capacity that your
vehicle can carry. If you are using E85 ethanol fuel the
maximum payload should not exceed 1000 lbs (454 kg).
Be sure to include the weight of the occupants as part of
your load. If you added any accessories or equipment
after your vehicle left the factory, remember to subtract
the weight of these things from the payload. Your dealer
can help you with this.
Remember not to exceed the Gross Axle Weight Rating
(GAWR) of the front or rear axle. See ªLoading Your
Vehicleº in the Index.
Two-Tiered Loading
By positioning four 2, x 6, wooden planks across the
width of the pickup box, you can create an upper load
platform. The planks must be inserted in the pickup box
depressions. The length of the planks must allow for at
least a 3/4 inch (2 cm) bearing surface on each end of
the plank.
When using this upper load platform, be sure the load is
securely tied down to prevent it from shifting. The
load's center of gravity should be positioned in a zone
over the rear axle.Any load that extends beyond the vehicle's taillamp area
must be properly marked according to local laws and
regulations.
Remember not to exceed the Gross Axle Weight Rating
(GAWR) of the rear axle. See ªLoading Your Vehicleº
in the Index.
Add-On Equipment
When you carry removable items, you may need to put a
limit on how many people you carry inside your vehicle.
Be sure to weigh your vehicle before you buy and install
the new equipment.
NOTICE:
Your warranty doesn't cover parts or
components that fail because of overloading.
Remember not to exceed the Gross Axle Weight Rating
(GAWR) of the rear axle. See ªLoading Your Vehicleº
in the Index.

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NOTICE:
Pulling a trailer improperly can damage your
vehicle and result in costly repairs not covered by
your warranty. To pull a trailer correctly, follow
the advice in this part, and see your dealer for
important information about towing a trailer
with your vehicle. Additional rear axle
maintenance is required for a vehicle used to tow
a trailer. See ªScheduled Maintenance Servicesº
in the Index.
Your vehicle may be able to tow a trailer. To identify
what the vehicle trailering capacity is for your vehicle,
you should read the information in ªWeight of the
Trailerº that appears later in this section.
If yours was built with trailering options, as many are,
it's ready for heavier trailers. But trailering is different
than just driving your vehicle by itself. Trailering means
changes in handling, durability and fuel economy.
Successful, safe trailering takes correct equipment, and
it has to be used properly.
That's the reason for this part. In it are many
time
-tested, important trailering tips and safety rules.
Many of these are important for your safety and that of
your passengers. So please read this section carefully
before you pull a trailer.

6-
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Section 6 Service and Appearance Care
Here you will find information about the care of your vehicle. This section begins with service and fuel information,
and then it shows how to check important fluid and lubricant levels. There is also technical information about your
vehicle, and a part devoted to its appearance care.
6
-2 Service
6
-3 Fuel (Gasoline)
6
-5 Fuel E-85 (85% Ethanol)
6
-7 Fuels in Foreign Countries
6
-7 Filling Your Tank
6
-9 Filling a Portable Fuel Container
6
-9 Checking Things Under the Hood
6
-13 Engine Oil
6
-18 Engine Air Cleaner/Filter
6
-19 Automatic Transmission Fluid
6
-23 Manual Transmission Fluid
6
-24 Hydraulic Clutch
6
-25 Rear Axle
6
-26 Four-Wheel Drive
6
-28 Engine Coolant
6
-31 Radiator Pressure Cap
6
-32 Power Steering Fluid6
-33 Windshield Washer Fluid
6
-34 Brakes
6
-38 Battery
6
-39 Bulb Replacement
6
-45 Windshield Wiper Blade Replacement
6
-47 Tires
6
-56 Appearance Care
6
-56 Cleaning the Inside of Your Vehicle
6
-59 Care of Safety Belts
6
-60 Cleaning the Outside of Your Vehicle
6
-64 GM Vehicle Care/Appearance Materials Chart
6
-65 Vehicle Identification Number (VIN)
6
-65 Service Parts Identification Label
6
-66 Electrical System
6
-72 Replacement Bulbs
6
-72 Capacities and Specifications
6
-74 Normal Maintenance Replacement Parts

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To insure quick starts in the wintertime, the E-85 fuel
must be formulated properly for your climate according
to ASTM specification D 5798. If you have trouble
starting on E
-85, it may be because your E-85 fuel is
not properly formulated for your climate. If this
happens, switching to gasoline or adding gasoline to
your fuel tank may improve starting. Your vehicle is
designed to accommodate a mixture of gasoline and
E
-85 fuel. For good starting and heater efficiency below
32
F (0
C), the fuel mix in the fuel tank should contain
no more than 70% ethanol.
E
-85 has less energy per gallon than gasoline, so you'll
need to refill your fuel tank more often when using E
-85
than when you're using gasoline. Use regular gasoline
when pulling a trailer. For payload capacity with ethanol
fuel see ªLoading Your Vehicleº in the Index.
NOTICE:
Some additives are not compatible with E-85 fuel
and may harm your fuel system. Damage caused
by additives wouldn't be covered by your new
vehicle warranty. Don't use additives with
E
-85 fuel.
NOTICE:
Your vehicle was not designed for fuel that
contains 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. Don't use fuel containing
methanol.