service GMC SIERRA 1500 2011 Repair Manual

Black plate (84,1)GMC Sierra Owner Manual - 2011
9-84 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 9‑87. For all other vehicles,
use only the unleaded gasoline
described under Recommended
Fuel on page 9‑84.
Recommended Fuel
For all vehicles except those with
the 6.2L V8 engine (VIN Code 2),
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 (85,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-85
If the vehicle has the 6.2L V8 engine
(VIN Code 2), use premium
unleaded gasoline with a posted
octane rating of 91 or higher.
You can also use regular unleaded
gasoline rated at 87 octane or
higher, but the vehicle's acceleration
could be slightly reduced, and
a slight audible knocking noise,
commonly referred to as spark
knock, might be heard. If the octane
is less than 87, you might notice
a heavy knocking noise when you
drive. If this occurs, use a gasoline
rated at 87 octane or higher as soon
as possible. Otherwise, you could
damage the engine. If heavy
knocking is heard when using
gasoline rated at 87 octane or
higher, the engine needs service.Gasoline Specifications
(U.S. and Canada Only)
At a minimum, gasoline should
meet ASTM specification
D 4814 in the United States
or CAN/CGSB‐3.5 or 3.511 in
Canada. Some gasolines contain
an octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). We recommend
against the use of gasolines
containing MMT. SeeFuel Additives
on page 9‑86 for additional
information.
California Fuel
Requirements
If the vehicle is certified to meet
California Emissions Standards,
it is designed to operate on fuels
that meet California specifications.
See the underhood emission control
label. If this fuel is not available in
states adopting California Emissions
Standards, the vehicle will operate
satisfactorily on fuels meeting
federal specifications, but emission
control system performance might
be affected. The malfunction
indicator lamp could turn on and the
vehicle might fail a smog‐check test.
See Malfunction Indicator Lamp on
page 5‑25. If this occurs, return to
your authorized dealer for diagnosis.
If it is determined that the condition
is caused by the type of fuel used,
repairs might not be covered by the
vehicle warranty.

Black plate (87,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-87
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 9‑84.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.
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.
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 (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.

Black plate (95,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-95
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 isclear 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 this
manual's Maintenance Schedule
or Index for more information.
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.
Trailer Towing
If the vehicle has a diesel engine,
see the Duramax diesel supplement
for more information.
If the vehicle is a hybrid, see
the hybrid supplement for more
information.
Do not tow a trailer during break‐in.
See New Vehicle Break-In on
page 9‑34 for more information.
{WARNING
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly.
For example, if the trailer is too
heavy, the brakes may not work
well or even at all. The driver and
passengers could be seriously
injured. The vehicle may also be
damaged; the resulting repairs
would not be covered by the
(Continued)
WARNING (Continued)
vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle.
Notice: Pulling a trailer
improperly can damage the
vehicle and result in costly
repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in
this section and see your dealer
for important information about
towing a trailer with the vehicle.
To identify the trailering capacity of
the vehicle, read the information in
“Weight of the Trailer” later in this
section.

Black plate (115,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-115
Heavy-DutyTrailer Wiring Harness
Package
For vehicles equipped with heavy
duty trailering, the harness is
connected to a bracket on the hitch
platform. 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 (116,1)GMC Sierra Owner Manual - 2011
9-116 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, an eight-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.

Black plate (120,1)GMC Sierra Owner Manual - 2011
9-120 Driving and Operating
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).
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.
On 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 9‑124
and Hill Start Assist (HSA) on
page 9‑70.

Black plate (121,1)GMC Sierra Owner Manual - 2011
Driving and Operating 9-121
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. Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and
must be adjusted any time vehicle
loading, trailer loading, or road
surface conditions change.
Setting the Trailer Gain properly
is needed for the best trailer
stopping performance. A trailer
that is over-gained may result in
locked trailer brakes. A trailer that
is under-gained may result in not
enough trailer braking. Both of
these conditions may result in
poorer stopping and stability of
the vehicle and trailer.

Black plate (124,1)GMC Sierra Owner Manual - 2011
9-124 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)
Trailer Sway Control (TSC)
2500 and 3500 series 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's 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.
Adding non‐dealer accessories can
affect the vehicle's performance.
See
Accessories and Modifications
on page 10‑3 for more information.

Black plate (1,1)GMC Sierra Owner Manual - 2011
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 . . . . . 10-11
Automatic Transmission Fluid (4-Speed
Transmission) . . . . . . . . . . . . . 10-13
Automatic Transmission Fluid (6-Speed
Transmission) . . . . . . . . . . . . . 10-16
Engine Air Cleaner/Filter . . . . 10-19
Cooling System . . . . . . . . . . . . 10-20
Engine Coolant . . . . . . . . . . . . . 10-22 Engine Overheating . . . . . . . . 10-25
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-28
Engine Fan . . . . . . . . . . . . . . . . . 10-28
Power Steering Fluid . . . . . . . 10-29
Washer Fluid . . . . . . . . . . . . . . . 10-29
Brakes . . . . . . . . . . . . . . . . . . . . . 10-30
Brake Fluid . . . . . . . . . . . . . . . . . 10-32
Battery . . . . . . . . . . . . . . . . . . . . . 10-34
Four-Wheel Drive . . . . . . . . . . . 10-34
Front Axle . . . . . . . . . . . . . . . . . . 10-36
Rear Axle . . . . . . . . . . . . . . . . . . 10-37
Noise Control System . . . . . . 10-38
Starter Switch Check . . . . . . . 10-39
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-40
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-40
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-40
Wiper Blade Replacement . . . . . . . . . . . . . . 10-41
Glass Replacement . . . . . . . . 10-41
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-42
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-44
Halogen Bulbs . . . . . . . . . . . . . . 10-44
Headlamps . . . . . . . . . . . . . . . . . 10-44
Pick-Up Box Identification and Fender Marker
Lamps . . . . . . . . . . . . . . . . . . . . 10-45
Taillamps (Chassis Cab Models) . . . . . . . . . . . . . . . . . . . 10-46
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-46
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . 10-47
License Plate Lamp . . . . . . . . 10-48
Replacement Bulbs . . . . . . . . . 10-48
Electrical System
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-49
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-50
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-50
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-54