Page 268 of 630

When the fuel tank is low the FUEL LEVEL LOW
message appears. SeeDIC Warnings and Messages
on page 4‑65for more information.
Here are some situations owners can experience with
the 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 fill 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 fuel tank's
capacity to fill it.
.The gage goes back to empty when the ignition is
turned off.
For a diesel engine, see “Fuel Gage”in the Diesel
Engine Supplement.
Low Fuel Warning Light
This light, under the fuel
gage, comes on briefly
while the engine is being
started.
This light and a chime comes on when the fuel tank is
low on fuel. The Driver Information Center also displays
a “FUEL LEVEL LOW” message. SeeDIC Warnings
and Messages
on page 4‑65for more information.
When fuel is added this light and message should go
off. If it does not, have the vehicle serviced by your
dealer/retailer.
4-50
Page 452 of 630

Keep a record with all parts receipts and list the
mileage and the date of any service work performed.
SeeMaintenance Record on page 7‑17.
Adding Equipment to the Outside of
the Vehicle
Things added to the outside of the vehicle can affect
the airflow around it. This can cause wind noise and
can affect fuel economy and windshield washer
performance. Check with your dealer/retailer before
adding equipment to the outside of the vehicle.
Fuel
For diesel engine vehicles, see “Diesel Fuel
Requirements and Fuel System” in the DURAMAX®
Diesel manual.
For vehicles with gasoline engines, please read this.
Gasoline
Use of the recommended fuel is an important part of
the proper maintenance of this vehicle. To help keep
the engine clean and maintain optimum vehicle
performance, we recommend the use of gasoline
advertised as TOP TIER Detergent Gasoline. Look for the TOP TIER label on the fuel pump to ensure
gasoline meets enhanced detergency standards
developed by auto companies. A list of marketers
providing TOP TIER Detergent Gasoline can be found
at www.toptiergas.com.
6-6
Page 456 of 630

Many service stations will not have an 85% ethanol
fuel (E85) pump available. The U.S. Department of
Energy has an alternative fuels website
(www.eere.energy.gov/afdc/infrastructure/locator.html)
that can help you find E85 fuel. Those stations that do
have E85 should have a label indicating ethanol
content. Do not use the fuel if the ethanol content is
greater than 85%.
At a minimum, E85 should meet ASTM Specification
D 5798. By definition, this means that fuel labeled
E85 will have an ethanol content between 70% and
85%. Filling the fuel tank with fuel mixtures that
do not meet ASTM specifications can affect driveability
and could cause the malfunction indicator lamp to
come on.To ensure quick starts in the wintertime, the E85 fuel
must be formulated properly for your climate according
to ASTM specification D 5798. If you have trouble
starting on E85, it could be because the E85 fuel is not
properly formulated for your climate. If this happens,
switching to gasoline or adding gasoline to the fuel tank
can improve starting. For good starting and heater
efficiency below 0°C (32°F), the fuel mix in the fuel tank
should contain no more than 70% ethanol. It is best not
to alternate repeatedly between gasoline and E85.
If you do switch fuels, it is recommended that you add
as much fuel as possible
—do not add less than
11 L (three gallons) when refueling. You should drive
the vehicle immediately after refueling for at least
11 km (seven miles) to allow the vehicle to adapt to
the change in ethanol concentration.
E85 has less energy per gallon than gasoline, so you
will need to refill the fuel tank more often when using
E85 than when you are using gasoline. See Filling the
Tank on page 6‑11.
6-10
Page 457 of 630

Notice:Some additives are not compatible with E85
fuel and can harm the vehicle's fuel system. Do not
add anything to E85. Damage caused by additives
would not be covered by the vehicle warranty.
Notice: This vehicle was not designed for fuel that
contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under the
vehicle warranty.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel might 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 would not be
covered by the vehicle warranty.
To check the fuel availability, ask an auto club,
or contact a major oil company that does business in
the country where you will be driving.
Filling the Tank
If the vehicle has the DURAMAX Diesel engine, see the
DURAMAX Diesel manual for more information.
{WARNING:
Fuel vapor burns violently and a fuel fire can
cause bad injuries. To help avoid injuries to you
and others, read and follow all the instructions on
the fuel pump island. Turn off the engine when
refueling. Do not smoke near fuel or when
refueling the vehicle. Do not use cellular phones.
Keep sparks, flames, and smoking materials away
from fuel. Do not leave the fuel pump unattended
when refueling the 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.
6-11
Page 458 of 630

The tethered fuel cap is located behind a hinged fuel
door on the driver side of the vehicle. If the vehicle
has E85 fuel capability, the fuel cap will be yellow
and state that E85 or gasoline can be used.
SeeFuel E85 (85% Ethanol) on page 6‑9.
To remove the fuel cap, turn it slowly counterclockwise.
{WARNING:
Fuel can spray out on you if you open the fuel cap
too quickly. If you spill fuel and then something
ignites it, you could be badly burned. This spray
can happen if the tank is nearly full, and is more
likely in hot weather. Open the fuel cap slowly and
wait for any hiss noise to stop. Then unscrew the
cap all the way.
If the vehicle is a dual fuel tank chassis cab model, and
it runs out of fuel, refuel the front fuel tank first to ensure
a quick restart.
Be careful not to spill fuel. Do not top off or overfill the
tank and wait a few seconds after you have finished
pumping before removing the nozzle. Clean fuel from
painted surfaces as soon as possible. See Washing
Your Vehicle on page 6‑113.
When replacing the fuel cap, turn it clockwise until it
clicks. It will require more effort to turn the fuel cap on
the last turn as you tighten it. Make sure the cap is fully
installed. The diagnostic system can determine if the
fuel cap has been left off or improperly installed. This
would allow fuel to evaporate into the atmosphere.
See Malfunction Indicator Lamp on page 4‑42.
6-12
Page 459 of 630

The TIGHTEN GAS CAP message displays on the
Driver Information Center (DIC) if the fuel cap is not
properly installed. SeeDIC Warnings and Messages
on
page 4‑65for more information.
{WARNING:
If a fire starts while you are refueling, do not
remove the nozzle. Shut off the flow of fuel by
shutting off the pump or by notifying the station
attendant. Leave the area immediately.
Notice: If you need a new fuel cap, be sure to get
the right type. Your dealer/retailer can get one for
you. If you get the wrong type, it may not fit
properly. This may cause the malfunction indicator
lamp to light and may damage the fuel tank and
emissions system. See Malfunction Indicator Lamp
on page 4‑42.
Filling a Portable Fuel Container
{WARNING:
Never fill a portable fuel container while it is in the
vehicle. Static electricity discharge from the
container can ignite the fuel vapor. You can be
badly burned and the vehicle damaged if this
occurs. To help avoid injury to you and others:
.Dispense fuel 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.
.Do not smoke while pumping fuel.
.Do not use a cellular phone while
pumping fuel.
6-13
Page 569 of 630
FusesUsage
7 Front Washer
8 Oxygen Sensor
9 Antilock Brakes System 2
10 Trailer Back-up Lamps 11 Driver Side Low-Beam Headlamp
12 Engine Control Module (Battery)
13 Fuel Injectors, Ignition
Coils (Right Side)
14 Transmission Control
Module (Battery)
15 Vehicle Back-up Lamps
16 Passenger Side Low-Beam Headlamp
17 Air Conditioning Compressor
18 Oxygen Sensors
19 Transmission Controls (Ignition)
20 Fuel Pump
21 Fuel System Control Module
22 Not Used
Fuses Usage
23 Not Used
24Fuel Injectors, Ignition
Coils (Left Side)
25 Trailer Park Lamps
26 Driver Side Park Lamps
27 Passenger Side Park Lamps
28 Fog Lamps
29 Horn
30 Passenger Side High-Beam
Headlamp
31 Daytime Running Lamps (DRL)
32 Driver Side High-Beam Headlamp
33 Daytime Running Lights 2
34 Sunroof
35 Key Ignition System, Theft
Deterrent System
36 Windshield Wiper
37 SEO B2 Upfitter Usage (Battery)
6-123
Page 570 of 630
FusesUsage
38 Electric Adjustable Pedals
39 Climate Controls (Battery)
40 Airbag System (Ignition)
41 Amplifier
42 Audio System
43Miscellaneous (Ignition), Cruise
Control
44 Not Used
45 Airbag System (Battery)
46 Instrument Panel Cluster
47 Power Take-Off
48 Auxiliary Climate Control (Ignition)
49 Center High-Mounted
Stoplamp (CHMSL)
50 Rear Defogger
Fuses Usage
51 Heated Mirrors
52 SEO B1 Upfitter Usage (Battery)
53Cigarette Lighter, Auxiliary
Power Outlet
54 SEO Upfitter Usage
55 Climate Controls (Ignition)
56 Engine Control Module, Secondary
Fuel Pump (Ignition)
J-Case Fuses
Usage
57 Cooling Fan 1
58 Not Used
59 Heavy Duty Antilock Brake System
60 Cooling Fan 2
61 Antilock Brake System 1
6-124