2008 CHEVROLET TAHOE fuel cap

If the Light Is On Steady
You might 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. SeeFilling the Tank on page 5-10. The
diagnostic system can determine if the fuel cap has
been left off or improperly installed. A loose or missing
fuel cap allows 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 vehicle’s electrical system might be wet. The
condition is usually 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
Gasoline Octane on page 5-6. Poor fuel quality causes
the engine not to run as efficiently as designed. You
might 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 might 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/retailer can check the vehicle. Your
dealer/retailer has the proper test equipment and
diagnostic tools to x any mechanical or electrical
problems that might have developed.
Emissions Inspection and
Maintenance Programs
Some state/provincial and local governments have or
might 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 the battery or if the
battery has run down. The diagnostic system is
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The gage will rst indicate empty before you are out of
fuel, and you should get more fuel as soon as
possible.
When the fuel tank is low, the FUEL LEVEL LOW
message will appear in the Driver Information Center
(DIC). SeeDIC Warnings and Messages on page 3-59
for more information.
Here are some situations you may experience with your
fuel gage. None of these indicate a problem with the
fuel gage.
At the gas station, the fuel pump shuts off before
the gage reads full.
It takes a little more or less fuel to ll up than the
fuel 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 ll the tank.
The gage goes back to empty when you turn off the
ignition.
If your vehicle is a Two-mode Hybrid, see the Two-mode
Hybrid manual for more information.
Low Fuel Warning Light
This light, under the fuel
gage, will come on briey
when you are starting
the engine.
This light and a chime will come on when the fuel tank
is low on fuel. There will also be a “FUEL LEVEL
LOW” message on the Driver Information Center, see
DIC Warnings and Messages on page 3-59for more
information. When you add fuel this light and message
should go off. If it does not, have your vehicle
serviced.
3-50

TIGHTEN GAS CAP
This message may display along with the check engine
light on the instrument panel cluster if the vehicle’s
fuel cap is not tightened properly. SeeMalfunction
Indicator Lamp on page 3-44. Reinstall the fuel cap fully.
SeeFilling the Tank on page 5-10. The diagnostic
system can determine if the fuel cap has been left off
or improperly installed. A loose or missing fuel
cap allows 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
This message displays when the Tire Pressure Monitor
System (TPMS) is re-learning the tire positions on
your vehicle. The tire positions must be re-learned after
rotating the tires or after replacing a tire or sensor.
SeeTire Inspection and Rotation on page 5-80,
Tire Pressure Monitor System on page 5-75, and
Inflation - Tire Pressure on page 5-74for more
information.
TRACTION CONTROL OFF
If your vehicle has StabiliTrak®, this message displays
when the Traction Control System (TCS) is turned
off. Adjust your driving accordingly. SeeStabiliTrak
®
System on page 4-6for more information.
TRANSMISSION HOT IDLE ENGINE
Notice:If you drive your vehicle while the
transmission uid is overheating and the
transmission temperature warning is displayed
on the instrument panel cluster and/or DIC, you
can damage the transmission. This could lead
to costly repairs that would not be covered by your
warranty. Do not drive your vehicle with overheated
transmission uid or while the transmission
temperature warning is displayed.
This message displays along with a continuous chime if
the transmission uid in the vehicle gets hot. Driving
with the transmission uid temperature high can cause
damage to the vehicle. Stop the vehicle and let it
idle to allow the transmission to cool. This message
clears and the chime stops when the uid temperature
reaches a safe level.
TURN SIGNAL ON
This message displays and a chime sounds if a turn
signal is left on for 3/4 of a mile (1.2 km). Move the turn
signal/multifunction lever to the off position.
3-66

Refer to your vehicle’s tire and loading information
label for specic information about your vehicle’s
capacity weight and seating positions. The
combined weight of the driver, passengers, and
cargo should never exceed your vehicle’s capacity
weight.
Certication/Tire Label
A vehicle specic Certication/Tire label is
found on the rear edge of the driver’s door.
The label shows the size of your vehicle’s original
tires and the ination pressures needed to
obtain the gross weight capacity of your vehicle.This is called Gross Vehicle Weight Rating
(GVWR). The GVWR includes the weight of the
vehicle, all occupants, fuel, and cargo.
The Certication/Tire label also tells you the
maximum weights for the front and rear axles,
called Gross Axle Weight Rating (GAWR). To nd
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.
The Certication/Tire label also contains
information about your Front Axle Reserve
Capacity.
And, if you do have a heavy load, you should
spread it out.
4-39

The plow your vehicle can carry depends on many
things, such as:
The options your vehicle came with, and the weight
of those options.
The weight and number of passengers you intend
to carry.
The weight of items you have added to your
vehicle.
The total weight of any additional cargo you intend
to carry.
Say, for example, you have a 700 lb (318 kg) snow
plow. The total weight of all occupants and cargo inside
the cab should not exceed 300 lb (135 kg). This
means that you may only be able to carry one
passenger. But, even this may be too much if you have
got other equipment already adding to the weight of
your vehicle.
Here are some guidelines for safely carrying a snow
plow on your vehicle:
Make sure the weight on the front and rear axles
does not exceed the axle rating for each.
For the front axle, if more cargo or passengers must
be carried, appropriate counter ballast must be
installed rear of the rear axle. Counter ballast must
be properly secured so it will not move during driving.
Follow the snow plow manufacturer’s
recommendations regarding rear ballast. Rear
ballast may be required to ensure a proper front and
rear weight distribution ratio, even though the actual
weight at the front axle may be less than the front
axle rating.
The snow plow manufacturer or installer can assist
you in determining the amount of rear ballast
required, to help make sure your snowplow/vehicle
combination does not exceed the GVW rating, the
front and rear axle ratings, and the front and rear
weight distribution ratio.
The total vehicle must not exceed the GVW rating.
Front axle reserve capacity is the difference between
your front Gross Axle Weight Rating (GAWR) and the
front axle weight of your vehicle with full fuel and
passengers. Basically, it is the amount of weight you can
add to your front axle before reaching your front GAWR.
The front axle reserve capacity for your vehicle can be
found in the lower right corner of the Certication/Tire
label, as shown.
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For example, adding a 700 lb (318 kg) snow plow
actually adds more than 700 lbs (318 kg) to the front
axle. Using the formula, if the snow plow is 4 ft (122 cm)
in front of the front axle and the wheel base is 10 ft
(305 cm), then:
W = 700 lb (318 kg)
A = 4 ft (122 cm)
W.B. = 10 ft (305 cm)
(W x (A + W.B.))/W.B. = (700 x (4 + 10))/10 = 980 lbs
(445 kg)
So, if your vehicle’s front axle reserve capacity is more
than 980 lbs (445 kg), you could add the snow plow
without exceeding the front GAWR.
You can add heavier equipment on the front of the vehicle
if you compensate for it by carrying fewer passengers,
less cargo, or by positioning cargo towards the rear. This
has the effect of reducing the load on the front. However,
the front GAWR, rear GAWR, and the Gross Vehicle
Weight Rating (GVWR) must never be exceeded.
{CAUTION:
On some vehicles that have certain front
mounted equipment, such as a snow plow, it
may be possible to load the front axle to the
front gross axle weight rating (GAWR) but not
have enough weight on the rear axle to have
proper braking performance. If your brakes can
not work properly, you could have a crash. To
help your brakes work properly when a snow
plow is installed, always follow the snow plow
manufacturer or installer’s recommendation for
rear ballast to ensure a proper front and rear
weight distribution ratio, even though the
actual front weight may be less than the front
GAWR, and the total vehicle weight is less
than the gross vehicle weight rating (GVWR).
Maintaining a proper front and rear weight
distribution ratio is necessary to provide
proper braking performance.
Total vehicle reserve capacity is the difference between
your GVWR and the weight of your vehicle with full
fuel and passengers. It is the amount of weight you can
add to your vehicle before reaching your GVWR.
4-44

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials Requirements.....5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside
of the Vehicle.............................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-6
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-7
Fuel E85 (85% Ethanol)..................................5-8
Fuels in Foreign Countries...............................5-9
Filling the Tank............................................5-10
Filling a Portable Fuel Container.....................5-13
Checking Things Under the Hood....................5-14
Hood Release..............................................5-14
Engine Compartment Overview.......................5-16
Engine Oil...................................................5-17
Engine Oil Life System..................................5-20
Engine Air Cleaner/Filter................................5-22
Automatic Transmission Fluid
(4-Speed Transmission)..............................5-24Automatic Transmission Fluid
(6-Speed Transmission)..............................5-27
Engine Coolant.............................................5-31
Coolant Surge Tank Pressure Cap..................5-34
Engine Overheating.......................................5-34
Overheated Engine Protection Operating Mode . . .5-36
Cooling System............................................5-37
Engine Fan Noise.........................................5-41
Power Steering Fluid.....................................5-42
Windshield Washer Fluid................................5-43
Brakes........................................................5-44
Battery........................................................5-47
Jump Starting...............................................5-48
Rear Axle.......................................................5-54
Four-Wheel Drive............................................5-55
Front Axle......................................................5-56
Headlamp Aiming...........................................5-58
Bulb Replacement..........................................5-61
Halogen Bulbs..............................................5-61
Taillamps, Turn Signal, Stoplamps
and Back-up Lamps...................................5-61
License Plate Lamp......................................5-63
Replacement Bulbs.......................................5-63
Windshield Wiper Blade Replacement..............5-64
Section 5 Service and Appearance Care
5-1

Filling the Tank
{CAUTION:
Fuel vapor burns violently and a fuel re can
cause bad injuries. To help avoid injuries to
you and others, read and follow all the
instructions on the pump island. Turn off your
engine when you are refueling. Do not smoke
if you are near fuel or refueling your vehicle.
Do not use cellular phones. Keep sparks,
ames, and smoking materials away from fuel.
Do not leave the fuel pump unattended when
refueling your vehicle. This is against the law
in some places. Do not re-enter the vehicle
while pumping fuel. Keep children away from
the fuel pump; never let children pump fuel.The tethered fuel cap is located behind a hinged fuel
door on the driver side of the vehicle. If the vehicle
is equipped with E85 fuel capability, a yellow cap with
the words “E85/gasoline” will appear.
5-10