2010 GMC SIERRA DENALI brakes

6. Adjust the Trailer Gain to just below the point oftrailer wheel lock-up, indicated by trailer wheel
squeal or tire smoke when a trailer wheel locks.
Trailer wheel lock-up may not occur if towing a
heavily loaded trailer. In this case, adjust the
Trailer Gain to the highest allowable setting for the
towing condition.
7. Re-adjust Trailer Gain any time vehicle loading, trailer loading or road surface conditions change or
if trailer wheel lock-up is noticed at any time while
towing.
Other ITBC Related DIC Messages
In addition to displaying TRAILER GAIN and TRAILER
OUTPUT through the DIC, trailer connection and ITBC
system status is displayed in the DIC.
TRAILER CONNECTED –This message will be briefly
displayed when a trailer with electric brakes is first
connected to the vehicle. This message will
automatically turn off in about ten seconds. The driver
can also acknowledge this message before it
automatically turns off. CHECK TRAILER WIRING
–This message will be
displayed if:
1. The ITBC system first 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.
5-54

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 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.
5-55

Driving with a Trailer
{WARNING:
When towing a trailer, exhaust gases may collect
at the rear of the vehicle and enter if the liftgate,
trunk/hatch, or rear-most window is open.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
To maximize safety when towing a trailer:
.Have the exhaust system inspected for leaks
and make necessary repairs before starting
a trip.
.Never drive with the liftgate, trunk/hatch,
or rear-most window open.(Continued)
WARNING: (Continued)
.Fully open the air outlets on or under the
instrument panel.
.Adjust the Climate Control system to a setting
that brings in only outside air and set the fan
speed to the highest setting. See Climate
Control System in the Index.
For more information about carbon monoxide, see
Engine Exhaust on page 3‑37.
Towing a trailer requires a certain amount of
experience. The combination you are driving is longer
and not as responsive as the vehicle itself. Get
acquainted with the handling and braking of the rig
before setting out for the open road.
Before starting, check all trailer hitch parts and
attachments, safety chains, electrical connectors,
lamps, tires and mirrors. If the trailer has electric
brakes, start the combination moving and then apply the
trailer brake controller by hand to be sure the
brakes work.
During the trip, check occasionally to be sure that the
load is secure and the lamps and any trailer brakes
still work.
5-56

Driving On Grades
Reduce speed and shift to a lower gearbeforestarting
down a long or steep downgrade. If the transmission is
not shifted down, the brakes might get hot and no
longer work well.
Vehicles can tow in D (Drive). Shift the transmission to
a lower gear if the transmission shifts too often under
heavy loads and/or hilly conditions.
The tow/haul mode may be used if the transmission
shifts too often. See Tow/Haul Mode on page 3‑32.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If the engine
is turned off immediately after towing at high altitude on
steep uphill grades, the vehicle may show signs similar
to engine overheating. To avoid this, let the engine run
while parked, preferably on level ground, with the
automatic transmission in P (Park) for a few minutes
before turning the engine off. If the overheat warning
comes on, see Engine Overheating on page 6‑34.
Parking on Hills
{WARNING:
Parking the vehicle on a hill with the trailer
attached can be dangerous. If something goes
wrong, the rig could start to move. People can be
injured, and both the vehicle and the trailer can be
damaged. When possible, always park the rig on
a flat surface.
If parking the rig on a hill: 1. Press the brake pedal, but do 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. Release the brake pedal.
5-58

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 near the data link connector 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
qualified 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.
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 figure 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 see Towing a Trailer
on
page 5‑42.
5-61

Section 6 Service and Appearance Care
Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4
Accessories and Modifications . . . . . . . . . . . . . . . . . . 6-4
California Proposition 65 Warning . . . . . . . . . . . . . . . 6-5
California Perchlorate Materials Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5
Doing Your Own Service Work . . . . . . . . . . . . . . . . . . 6-5
Adding Equipment to the Outside of the Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-6
Gasoline Octane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Gasoline Specifications . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
California Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Additives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Fuel E85 (85% Ethanol) . . . . . . . . . . . . . . . . . . . . . . . . . 6-9
Fuels in Foreign Countries . . . . . . . . . . . . . . . . . . . . . 6-10
Filling the Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-10
Filling a Portable Fuel Container . . . . . . . . . . . . . . . 6-13
Checking Things Under the Hood . . . . . . . . . . . . . . .6-14
Hood Release . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-14
Engine Compartment Overview . . . . . . . . . . . . . . . . 6-16
Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-18
Engine Oil Life System . . . . . . . . . . . . . . . . . . . . . . . . 6-20
Engine Air Cleaner/Filter . . . . . . . . . . . . . . . . . . . . . . . 6-22
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . 6-24
Cooling System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-28 Engine Coolant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-29
Engine Overheating . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-34
Overheated Engine Protection
Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37
Engine Fan Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-37
Power Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 6-38
Windshield Washer Fluid . . . . . . . . . . . . . . . . . . . . . . 6-39
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-40
Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-43
Jump Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-44
All-Wheel Drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-49
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-50
Front Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-51
Headlamp Aiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-52
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Headlamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-55
Center High-Mounted Stoplamp (CHMSL) and Cargo Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-57
Taillamps, Turn Signal, Stoplamps and Back-up Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-58
License Plate Lamp . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Replacement Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-60
Windshield Wiper Blade Replacement . . . . . . . . . . .6-61
6-1

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 Modifications
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 certified parts, including
control module modifications, is 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 2‑72.
6-4

A.Engine Air Cleaner/Filter on page 6‑22.
B. Coolant Surge Tank and Pressure Cap. See Cooling System on page 6‑28.
C. Remote Positive (+) Terminal. See Jump Starting
on page 6‑44.
D. Battery on page 6‑43.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
under Engine Oil on page 6‑18.
F. Automatic Transmission Dipstick (Out of View). See “Checking the Fluid Level” underAutomatic
Transmission Fluid on page 6‑24.
G. Remote Negative (−) Terminal (GND) (Out of View). See Jump Starting on page 6‑44. H. Engine Oil Dipstick (Out of View). See
“Checking
Engine Oil” underEngine Oil on page 6‑18.
I. Engine Cooling Fan (Out of View). See Cooling
System on page 6‑28.
J. Power Steering Fluid Reservoir (Out of View). See Power Steering Fluid on page 6‑38.
K. Brake Master Cylinder Reservoir. See “Brake
Fluid” under Brakes on page 6‑40.
L. Underhood Fuse Block on page 6‑118.
M. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on
page 6‑39.
6-17