service GMC SIERRA 2009 Repair Manual

A. Trailer Gain Setting
B. Power Output to Trailer Brakes
C. No trailer with electric brakes connected or fault
present
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 rst 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 rst 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 anytime 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 the 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.
4-73

The Trailer Output will indicate “------“ontheTrailer
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 in 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 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 specic 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.
Use the following procedure to correctly adjust Trailer
Gain for each towing condition:
1. Make sure the trailer brakes are in proper working
condition.
2. Connect a properly loaded trailer to the vehicle
and make all necessary mechanical and electrical
connections. SeeLoading the Vehicle on page 4-32
for more information.
4-74

CHECK TRAILER WIRING – This message will be
displayed if:
1. The ITBC system rst determines connection to
a trailer with electric brakes and then the trailer
harness becomes disconnected from the vehicle.
If the disconnect occurs while the vehicle is
stationary, this message will automatically turn
off in about thirty seconds. This message will also
turn off if the driver acknowledges this message
off or if the trailer harness is re-connected.
If the disconnect occurs while the vehicle is moving,
this message will continue until the ignition is turned
off. This message will also turn off if the driver
acknowledges this message off or if the trailer
harness is re-connected.
2. There is an electrical fault in the wiring to the
electric trailer brakes. This message will continue
as long as there is an electrical fault in the trailer
wiring. This message will also turn off if the driver
acknowledges this message off.
To determine if the electrical fault is on the vehicle side
or trailer side of the trailer wiring harness connection,
do the following:
1. Disconnect the trailer wiring harness from the
vehicle.
2. Turn the ignition OFF.3. Wait ten seconds, then turn the ignition back
to RUN.
4. If the CHECK TRAILER WIRING message
re-appears, the electrical fault is on the vehicle side.
If the CHECK TRAILER WIRING message only
re-appears when connecting the trailer wiring
harness to the vehicle, the electrical fault is on
the trailer side.
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.
4-76

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 uid,
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 Wiring Harness
The vehicle is equipped with one of the following
wiring harnesses for towing a trailer or hauling a
slide-in camper.
Basic Trailer Wiring
All regular, extended cab and crew cab pickups have a
seven-wire trailer towing harness.
For vehicles not equipped with heavy duty trailering,
the harness is secured to the vehicle’s frame behind the
spare tire mount. The harness requires the installation
of a trailer connector, which is available through
your dealer/retailer.
If towing a light-duty trailer with a standard four-way
round pin connector, an adapter is available from your
dealer/retailer.
4-81

Heavy-Duty Trailer 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/retailer or a qualied 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/retailer or authorized
service center install the required fuse.
If charging a remote (non-vehicle) battery, press the
tow/haul mode button 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, turn on the headlamps as a second way to boost
the vehicle system and charge the battery.
4-82

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
It should be installed by your dealer/retailer or a
qualied service center.
If the vehicle is equipped with an ITBC, the blunt cuts
exist, but are not connected further in the harness.
If an aftermarket trailer brake controller is installed,
the ITBC must be disconnected. Do not power
both ITBC and aftermarket controllers to control
the trailer brakes at the same time.
Auxiliary Battery
The auxiliary battery provision can be used to supply
electrical power to additional equipment that may be
added, such as a slide-in camper. If the vehicle has this
provision, this relay will be located on the drivers side of
the vehicle, next to the underhood electrical center.Be sure to follow the proper installation instructions
that are included with any electrical equipment that
is installed.
Notice:Leaving electrical equipment on for
extended periods will drain the battery. Always turn
off electrical equipment when not in use and do
not use equipment that exceeds the maximum
amperage rating for the auxiliary battery provision.
Trailer Recommendations
Subtract the hitch loads from the Cargo Weight Rating
(CWR). CWR is the maximum weight of the load the
vehicle can carry. It does not include the weight of the
people inside, but you can gure about 150 lbs. (68 kg)
for each passenger. The total cargo load must not be
more than the vehicles CWR.
Weigh the vehicle with the trailer attached, so
the GVWR or GAWR are not exceeded. If using a
weight-distributing hitch, weigh the vehicle without
the spring bars in place.
The best performance is obtained by correctly spreading
out the weight of the load and choosing the correct
hitch and trailer brakes.
For more information seeTowing a Trailer on page 4-51.
4-84

Service............................................................5-4
Accessories and Modications..........................5-4
California Proposition 65 Warning.....................5-5
California Perchlorate Materials
Requirements.............................................5-5
Doing Your Own Service Work.........................5-5
Adding Equipment to the Outside of
the Vehicle.................................................5-6
Fuel................................................................5-6
Gasoline Octane............................................5-6
Gasoline Specications....................................5-7
California Fuel...............................................5-7
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.....................5-12
Checking Things Under the Hood....................5-12
Hood Release..............................................5-13
Engine Compartment Overview.......................5-14
Engine Oil...................................................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-19Automatic Transmission Fluid (4-Speed
Transmission)...........................................5-21
Automatic Transmission Fluid (6-Speed
Transmission)...........................................5-24
Cooling System............................................5-28
Engine Coolant.............................................5-29
Engine Overheating.......................................5-34
Overheated Engine Protection
Operating Mode........................................5-37
Engine Fan Noise.........................................5-37
Power Steering Fluid.....................................5-38
Windshield Washer Fluid................................5-39
Brakes........................................................5-40
Battery........................................................5-43
Jump Starting...............................................5-44
Rear Axle.......................................................5-49
Four-Wheel Drive............................................5-51
Front Axle......................................................5-53
Noise Control System.....................................5-54
Tampering with Noise Control System
Prohibited.................................................5-54
Headlamp Aiming...........................................5-55
Section 5 Service and Appearance Care
5-1

Bulb Replacement..........................................5-58
Halogen Bulbs..............................................5-58
Headlamps..................................................5-58
Center High-Mounted Stoplamp (CHMSL)
and Cargo Lamp.......................................5-59
Pickup Box Identication and Fender
Marker Lamps...........................................5-60
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
Tires..............................................................5-65
Tire Sidewall Labeling...................................5-66
Tire Terminology and Denitions.....................5-70
Ination - Tire Pressure.................................5-73
High-Speed Operation...................................5-74
Dual Tire Operation.......................................5-75
Tire Pressure Monitor System.........................5-76
Tire Pressure Monitor Operation.....................5-77
Tire Inspection and Rotation...........................5-81
When It Is Time for New Tires.......................5-83
Buying New Tires.........................................5-84
Different Size Tires and Wheels......................5-86Uniform Tire Quality Grading..........................5-86
Wheel Alignment and Tire Balance..................5-88
Wheel Replacement......................................5-89
Tire Chains..................................................5-90
If a Tire Goes Flat........................................5-91
Changing a Flat Tire.....................................5-92
Removing the Spare Tire and Tools................5-93
Removing the Flat Tire and Installing
the Spare Tire..........................................5-98
Secondary Latch System..............................5-106
Storing a Flat or Spare Tire and Tools...........5-109
Spare Tire.................................................5-113
Appearance Care
..........................................5-113
Interior Cleaning.........................................5-113
Fabric/Carpet..............................................5-115
Leather......................................................5-115
Instrument Panel, Vinyl, and Other
Plastic Surfaces.......................................5-116
Care of Safety Belts....................................5-116
Weatherstrips.............................................5-116
Washing Your Vehicle..................................5-117
Cleaning Exterior Lamps/Lenses....................5-117
Finish Care................................................5-118
Windshield and Wiper Blades.......................5-118
Section 5 Service and Appearance Care
5-2

Aluminum or Chrome-Plated Wheels
and Trim................................................5-119
Tires.........................................................5-120
Sheet Metal Damage...................................5-120
Finish Damage...........................................5-120
Underbody Maintenance...............................5-120
Chemical Paint Spotting...............................5-120
Vehicle Identication.....................................5-121
Vehicle Identication Number (VIN)................5-121
Service Parts Identication Label...................5-121Electrical System..........................................5-122
Add-On Electrical Equipment.........................5-122
Windshield Wiper Fuses...............................5-122
Power Windows and Other
Power Options........................................5-122
Fuses and Circuit Breakers..........................5-122
Instrument Panel Fuse Block........................5-123
Center Instrument Panel Fuse Block..............5-125
Underhood Fuse Block................................5-126
Capacities and Specications........................5-129
Section 5 Service and Appearance Care
5-3

Service
For service and parts needs, visit your dealer/retailer.
You will receive genuine GM parts and GM-trained and
supported service people.
Genuine GM parts have one of these marks:
Accessories and Modications
When non-dealer/non-retailer accessories are added to
the vehicle, they can affect vehicle performance and
safety, including such things as airbags, braking, stability,
ride and handling, emissions systems, aerodynamics,
durability, and electronic systems like antilock brakes,
traction control, and stability control. Some of these
accessories could even cause malfunction or damage
not covered by the vehicle warranty.
Damage to vehicle components resulting from the
installation or use of non-GM certied parts, including
control module modications, are not covered under the
terms of the vehicle warranty and may affect remaining
warranty coverage for affected parts.
GM Accessories are designed to complement and
function with other systems on the vehicle. Your GM
dealer/retailer can accessorize the vehicle using genuine
GM Accessories. When you go to your GM
dealer/retailer and ask for GM Accessories, you will
know that GM-trained and supported service technicians
will perform the work using genuine GM Accessories.
Also, seeAdding Equipment to Your Airbag-Equipped
Vehicle on page 1-89.
5-4