service CHEVROLET SILVERADO 2012 2.G Repair Manual

Black plate (76,1)Chevrolet Silverado Owner Manual - 2012
9-76 Driving and Operating
Fuel
For diesel engine vehicles, see
“Fuel for Diesel Engines”in the
Duramax Diesel Supplement.
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.
The eighth digit of the Vehicle
Identification Number (VIN) shows
the code letter or number that
identifies the vehicle's engine.
The VIN is at the top left of the
instrument panel. See Vehicle
Identification Number (VIN) on
page 12‑1.
Vehicles that have a FlexFuel badge
and a yellow fuel cap can use either
unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85). See
Fuel E85 (85% Ethanol) on
page 9‑78. For all other vehicles,
use only the unleaded gasoline
described under Recommended
Fuel on page 9‑76.
Recommended Fuel
Use regular unleaded gasoline with
a posted octane rating of 87 or
higher. If the octane rating is less
than 87, an audible knocking noise,
commonly referred to as spark
knock, might be heard when driving.
If this occurs, use a gasoline rated
at 87 octane or higher as soon as
possible. If heavy knocking is
heard when using gasoline rated
at 87 octane or higher, the engine
needs service.

Black plate (78,1)Chevrolet Silverado Owner Manual - 2012
9-78 Driving and Operating
However, some gasolines contain
only the minimum amount of
additive required to meet U.S.
Environmental Protection Agency
regulations. To help keep fuel
injectors and intake valves clean
and avoid problems due to dirty
injectors or valves, look for gasoline
that is 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 the auto companies. A list of
marketers providing TOP TIER
Detergent Gasoline can be found at
www.toptiergas.com.
For customers who do not use TOP
TIER Detergent Gasoline regularly,
one bottle of GM Fuel System
Treatment PLUS, added to the fuel
tank at every engine oil change,
can help clean deposits from fuel
injectors and intake valves. GM Fuel
System Treatment PLUS is the only
gasoline additive recommended by
General Motors. It is available at
your dealer.Gasolines containing oxygenates,
such as ethers and ethanol,
and reformulated gasolines
might be available in your area.
We recommend that you use these
gasolines, if they comply with the
specifications described earlier.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must not be used in
vehicles that were not designed for
those fuels.
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.
Some gasolines that are
not reformulated for low
emissions can contain an
octane-enhancing additive called
methylcyclopentadienyl manganese tricarbonyl (MMT); ask the attendant
where you buy gasoline whether the
fuel contains MMT. We recommend
against the use of such gasolines.
Fuels containing MMT can reduce
spark plug life and affect emission
control system performance.
The malfunction indicator lamp
might turn on. If this occurs, return
to your dealer for service.
Fuel E85 (85% Ethanol)
Vehicles that have a FlexFuel badge
and a yellow fuel cap can use either
unleaded gasoline or ethanol fuel
containing up to 85% ethanol (E85).
For all other vehicles, use only the
unleaded gasoline described under
Recommended Fuel on page 9‑76.
We encourage the use of E85 in
vehicles that are designed to use it.
The ethanol in E85 is a
“renewable”
fuel, meaning it is made from
renewable sources such as corn
and other crops.

Black plate (79,1)Chevrolet Silverado Owner Manual - 2012
Driving and Operating 9-79
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.afdc.energy.gov/afdc/
locator/stations/) 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 or
CGSB Specification 3.512.
Filling the tank with fuel mixtures
that do not meet ASTM or CGSB
specifications can affect driveability
and could cause the malfunction
indicator lamp to come on. As the
outside temperature approaches
freezing, ethanol fuel distributors
should supply winter grade
ethanol, the same as with
unleaded gasoline. Winter grade
blends typically do not exceed
70% ethanol (E70).The starting characteristics of
ethanol make it more difficult to
start below 0°C (32°F), which may
lead to longer start/crank times.
Engine start on ethanol fuels down
to
−30°C (−20°F) is possible,
provided a winter grade ethanol
blend is used.
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 (3 gal) when refueling.
You should drive the vehicle
immediately after refueling for at
least 11 km (7 mi) to allow the
vehicle to adapt to the change in
ethanol concentration.
E85 has less energy per liter
(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 9‑80. 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.

Black plate (85,1)Chevrolet Silverado Owner Manual - 2012
Driving and Operating 9-85
If parking the rig on a hill:
1. Press the brake pedal, butdo not shift into P (Park) yet.
Turn the 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 brake pedal. Then apply the parking brake
and shift into P (Park).
5. If the vehicle is four-wheel-drive, be sure the transfer case is in a
drive gear and not in N (Neutral).
6. Release the brake pedal.{WARNING
It can be dangerous to get out of
the vehicle if the shift lever is not
fully in P (Park) with the parking
brake firmly set. The vehicle
can roll.
If the engine has been left
running, the vehicle can move
suddenly. You or others could be
injured. To be sure the vehicle will
not move, even when on fairly
level ground, use the steps that
follow.
Always put the shift lever fully in
P (Park) with the parking brake
firmly set.
If the transfer case on a
four-wheel-drive vehicle is in
N (Neutral), the vehicle will be
free to roll, even if the shift lever
is in P (Park). Be sure the transfer
case is in a drive gear —not in
N (Neutral).
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks.
7. Stop and have someone pick up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer.
See Maintenance Schedule on
page 11‑3. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.

Black plate (105,1)Chevrolet Silverado Owner Manual - 2012
Driving and Operating 9-105
If towing a light‐duty trailer with a
standard four‐way round pin
connector, an adapter is available
from your dealer.
Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy
duty trailering, the harness
connector is mounted in the bumper.The seven-wire harness contains
the following trailer circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn
Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed*
.Dark Blue: Trailer Brake*
*The fuses for these two circuits are
installed in the underhood electrical
center, but the wires are not
connected. They should be
connected by your dealer or a
qualified service center. The fuse
and wire for the ITBC is factory
installed and connected if the
vehicle is equipped with an ITBC. The fuse for the battery feed is
not required if the vehicle has an
auxiliary battery. If the vehicle does
not have an auxiliary battery, have
your dealer or authorized service
center install the required fuse.
If charging a remote (non-vehicle)
battery, press the Tow/Haul Mode
button, if equipped, located at the
end of the shift lever. This will boost
the vehicle system voltage and
properly charge the battery. If the
trailer is too light for Tow/Haul
Mode, or the vehicle is not
equipped with Tow/Haul, turn on
the headlamps as a second way
to boost the vehicle system and
charge the battery.

Black plate (106,1)Chevrolet Silverado Owner Manual - 2012
9-106 Driving and Operating
Camper/Fifth-Wheel Trailer
Wiring Package
The seven-wire camper harness is
located under the front edge of the
pickup box on the driver side of the
vehicle, attached to the frame
bracket. A connector must be
added to the wiring harness which
connects to the camper.
The harness contains the following
camper/trailer circuits:
.Yellow: Left Stop/Turn Signal
.Dark Green: Right Stop/Turn
Signal
.Brown: Taillamps
.White: Ground
.Light Green: Back-up Lamps
.Red: Battery Feed
.Dark Blue: Trailer Brake
If the vehicle is equipped with the
“Heavy-Duty Trailering”option,
please refer to “Heavy-Duty Trailer
Wiring Package” earlier in this
section.
When the camper-wiring harness is
ordered without the heavy-duty
trailering package, a seven-wire
harness with a seven-pin connector
is located at the rear of the vehicle
and is tied to the vehicle's frame.
Electric Brake Control Wiring
Provisions
These wiring provisions are
included with the vehicle as part of
the trailer wiring package. These
provisions are for an electric brake
controller. The instrument panel
contains blunt cut wires behind the
steering column for the trailer brake
controller. The harness contains the
following wires:
.Dark Blue: Brake Signal to
Trailer Connector
.Red/Black: Battery
.Light Blue/White: Brake Switch
.White: Ground
The harness should be installed by
your dealer or a qualified service
center.
If the vehicle is equipped with an
Integrated Trailer Brake Control
(ITBC) System, the blunt cuts exist,
but are not connected further in the

Black plate (110,1)Chevrolet Silverado Owner Manual - 2012
9-110 Driving and Operating
The control panel allows adjustment
to the amount of output, referred to
as trailer gain, available to the
electric trailer brakes and allows
manual application of the trailer
brakes. The Trailer Brake Control
Panel is used along with the Trailer
Brake Display Page on the DIC to
adjust and display power output to
the trailer brakes.
Trailer Brake DIC Display Page
The ITBC system displays
messages on the vehicle’s Driver
Information Center (DIC). See
Driver Information Center (DIC) on
page 5‑32for more information.
The display page indicates Trailer
Gain setting, power output to the
electric trailer brakes, trailer
connection, and system operational
status. The Trailer Brake Display Page can
be displayed by performing any of
the following actions:
.Scrolling through the DIC menu
pages using the odometer trip
stem or the DIC Vehicle
Information button (if equipped).
.Pressing a Trailer Gain
button—If the Trailer Brake
Display Page is not currently
displayed, pressing a Trailer
Gain button will first recall the
current Trailer Gain setting.
After the Trailer Brake Display
Page is displayed, each press
and release of the gain buttons
will then cause the Trailer Gain
setting to change.
.Activating the Manual Trailer
Brake Apply lever.
.Connecting a trailer equipped
with electric trailer brakes.All DIC warning and service
messages must first be
acknowledged by the driver by
pressing the odometer trip stem or
the DIC Vehicle Information button
(if equipped) before the Trailer
Brake Display Page can be
displayed and Trailer Gain can be
adjusted.
TRAILER GAIN: This setting is
displayed any time the Trailer Brake
Display Page is active. This setting
can be adjusted from 0.0 to 10.0
with either a trailer connected or
disconnected. To adjust the Trailer
Gain, press one of the Trailer Gain
adjustment buttons located on the
Trailer Brake Control Panel. Press
and hold a gain button to cause the
Trailer Gain to continuously adjust.
To turn the output to the trailer off,
adjust the Trailer Gain setting to
0.0 (zero).

Black plate (111,1)Chevrolet Silverado Owner Manual - 2012
Driving and Operating 9-111
0.0 (zero) gain is the factory default
setting. To properly adjust trailer
gain, see“Trailer Gain Adjustment
Procedure” later in this section.
TRAILER OUTPUT: This is
displayed any time a trailer with
electric brakes is connected.
Output to the electric brakes is
based on the amount of vehicle
braking present and relative to the
Trailer Gain setting. Output is
displayed from 0 to 10 bars for
each gain setting.
Non-hybrid vehicles with Trailer
Sway Control (TSC) or Hill Start
Assist (HSA), output to the electric
trailer brakes may be displayed
when the systems are active.
See Trailer Sway Control (TSC) on
page 9‑114 andHill Start Assist
(HSA) on page 9‑62. The Trailer Output will indicate
“- - - - - -”
on the Trailer Brake
Display Page whenever the
following occur:
.No trailer is connected
.A trailer without electric brakes
is connected (no DIC message
is displayed)
.A trailer with electric brakes
has become disconnected
(a CHECK TRAILER WIRING
message will also be displayed
on the DIC)
.There is a fault present in the
wiring to the electric trailer
brakes (a CHECK TRAILER
WIRING message will also be
displayed on the DIC)
.There is a fault in the ITBC
system (a SERVICE TRAILER
BRAKE SYSTEM message will
also be displayed in the DIC) Manual Trailer Brake Apply
The Manual Trailer Brake Apply
Lever is located on the Trailer Brake
Control Panel and is used to apply
the trailer
’s electric brakes
independent of the vehicle’s brakes.
This lever is used in the Trailer Gain
Adjustment Procedure to properly
adjust the power output to the trailer
brakes. Sliding the lever to the left
will apply only the trailer brakes.
The power output to the trailer is
indicated in the Trailer Brake
Display Page on the DIC. If the
vehicle’s service brakes are applied
while using the Manual Trailer Brake
Apply Lever, the trailer output power
will be the greater of the two.
The trailer's and the vehicle's brake
lamps will come on when either
vehicle braking or manual trailer
brakes are applied.

Black plate (114,1)Chevrolet Silverado Owner Manual - 2012
9-114 Driving and Operating
SERVICE TRAILER BRAKE
SYSTEM: This message
will be displayed when there is a
problem with the ITBC system.
If this message persists over
multiple ignition cycles, there is a
problem with the ITBC system.
Take the vehicle to an authorized
GM dealer to have the ITBC system
diagnosed and repaired.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message is
displayed while driving the vehicle,
power is no longer available to the
trailer brakes. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service.An authorized GM dealer may be
able to diagnose and repair
problems with the trailer. However,
any diagnosis and repair of the
trailer is not covered under the
vehicle warranty. Please contact
your trailer dealer for assistance
with trailer repairs and trailer
warranty information.
Trailer Sway
Control (TSC)
Non-hybrid vehicles with StabiliTrak
have a Trailer Sway Control (TSC)
feature. If the vehicle is towing a
trailer and the system detects that
the trailer is swaying, the vehicle
brakes are applied without the
driver pressing the brake pedal.
If the vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, StabiliTrak may
also apply the trailer brakes.
The TCS/StabiliTrak warning light
will flash on the instrument panel
cluster to notify the driver to reduce
speed. If the trailer continues to
sway, StabiliTrak will reduce engine
torque to help slow the vehicle.
See
StabiliTrak
®System on
page 9‑62 for more information.
Adding non‐dealer accessories can
affect the vehicle performance.
See Accessories and Modifications
on page 10‑3 for more information.

Black plate (1,1)Chevrolet Silverado Owner Manual - 2012
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-3
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-4
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil . . . . . . . . . . . . . . . . . . . 10-7
Engine Oil Life System . . . . . 10-10
Automatic Transmission Fluid (4-Speed Transmission) . . . 10-11
Automatic Transmission Fluid (6-Speed
Transmission) . . . . . . . . . . . . . 10-14
Manual Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-17
Hydraulic Clutch . . . . . . . . . . . . 10-17 Engine Air Cleaner/Filter . . . . 10-17
Cooling System . . . . . . . . . . . . 10-19
Engine Coolant . . . . . . . . . . . . . 10-20
Engine Overheating . . . . . . . . 10-23
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-26
Engine Fan . . . . . . . . . . . . . . . . . 10-26
Power Steering Fluid . . . . . . . 10-27
Washer Fluid . . . . . . . . . . . . . . . 10-28
Brakes . . . . . . . . . . . . . . . . . . . . . 10-28
Brake Fluid . . . . . . . . . . . . . . . . . 10-30
Battery . . . . . . . . . . . . . . . . . . . . . 10-31
Four-Wheel Drive . . . . . . . . . . . 10-32
Front Axle . . . . . . . . . . . . . . . . . . 10-33
Rear Axle . . . . . . . . . . . . . . . . . . 10-34
Noise Control System . . . . . . 10-36
Starter Switch Check . . . . . . . 10-36
Automatic Transmission Shift Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-37
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-38
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-38
Wiper Blade Replacement . . . . . . . . . . . . . . 10-39
Glass Replacement . . . . . . . . 10-39
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-39
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-42
Halogen Bulbs . . . . . . . . . . . . . . 10-42
Headlamps, Front Turn Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-42
Pick-Up Box Identification and Fender Marker
Lamps . . . . . . . . . . . . . . . . . . . . 10-43
Taillamps (Chassis Cab Models) . . . . . . . . . . . . . . . . . . . 10-43
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-44
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . 10-44
License Plate Lamp . . . . . . . . 10-45
Replacement Bulbs . . . . . . . . . 10-45