2009 GMC YUKON brake

Parking on Hills
{CAUTION:
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
at 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. 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.
{CAUTION:
It can be dangerous to get out of the vehicle if the
shift lever is not fully in P (Park) with the parking
brake rmly 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 rmly set.
4-70

Leaving After Parking on a Hill
1. Apply and hold the brake pedal while you:
Start the engine
Shift into a gear
Release the parking brake
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. 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
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 the following wiring
harnesses for towing a trailer.
Basic Trailer Wiring
The trailer wiring harness, with a seven-pin connector,
is located at the rear of the vehicle and is tied to
the vehicle’s frame. The harness connector can be
plugged into a seven-pin universal heavy-duty trailer
connector available through your dealer/retailer.
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.
4-71

Heavy-Duty Trailer Wiring Harness
Package
The vehicle is equipped with the seven-wire trailer
towing harness. This harness with a seven-pin universal
trailer connector is attached 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.
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.
4-72

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
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.
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 4-52.
4-73

Service............................................................5-3
Accessories and Modications..........................5-3
California Proposition 65 Warning.....................5-4
California Perchlorate Materials
Requirements.............................................5-4
Doing Your Own Service Work.........................5-4
Adding Equipment to the Outside of
the Vehicle.................................................5-5
Fuel................................................................5-5
Gasoline Octane............................................5-5
Gasoline Specications....................................5-6
California Fuel...............................................5-6
Additives.......................................................5-6
Fuel E85 (85% Ethanol)..................................5-7
Fuels in Foreign Countries...............................5-8
Filling the Tank..............................................5-9
Filling a Portable Fuel Container.....................5-11
Checking Things Under the Hood....................5-12
Hood Release..............................................5-12
Engine Compartment Overview.......................5-14
Engine Oil...................................................5-15
Engine Oil Life System..................................5-18
Engine Air Cleaner/Filter................................5-19
Automatic Transmission Fluid (4-Speed
Transmission)...........................................5-21Automatic Transmission Fluid (6-Speed
Transmission)...........................................5-24
Cooling System............................................5-28
Engine Coolant.............................................5-29
Engine Overheating.......................................5-35
Overheated Engine Protection
Operating Mode........................................5-37
Engine Fan Noise.........................................5-38
Power Steering Fluid.....................................5-38
Windshield Washer Fluid................................5-39
Brakes........................................................5-41
Battery........................................................5-44
Jump Starting...............................................5-45
Rear Axle.......................................................5-50
Four-Wheel Drive............................................5-52
Front Axle......................................................5-53
Headlamp Aiming...........................................5-54
Bulb Replacement..........................................5-57
Halogen Bulbs..............................................5-57
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-58
License Plate Lamp......................................5-59
Replacement Bulbs.......................................5-60
Windshield Wiper Blade Replacement..............5-60
Section 5 Service and Appearance Care
5-1

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 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 1-96.
5-3

Checking Things Under
the Hood
{CAUTION:
An electric fan under the hood can start up and
injure you even when the engine is not running.
Keep hands, clothing, and tools away from any
underhood electric fan.
{CAUTION:
Things that burn can get on hot engine parts and
start a re. These include liquids like fuel, oil,
coolant, brake uid, windshield washer and other
uids, and plastic or rubber. You or others could
be burned. Be careful not to drop or spill things
that will burn onto a hot engine.
Hood Release
To open the hood:
1. Pull the handle with
this symbol on it. It is
located inside the
vehicle to the lower left
of the steering wheel.
5-12

A.Engine Air Cleaner/Filter on page 5-19.
B. Coolant Surge Tank and Pressure Cap. SeeCooling
System on page 5-28.
C. Remote Positive (+) Terminal. SeeJump Starting on
page 5-45.
D.Battery on page 5-44.
E. Engine Oil Fill Cap. See “When to Add Engine Oil”
underEngine Oil on page 5-15.
F. Automatic Transmission Dipstick. See “Checking the
Fluid Level” underAutomatic Transmission Fluid
(4-Speed Transmission) on page 5-21orAutomatic
Transmission Fluid (6-Speed Transmission) on
page 5-24.
G. Remote Negative (−) Terminal (Out of View).
SeeJump Starting on page 5-45.
H. Engine Oil Dipstick (Out of View). See “Checking
Engine Oil” underEngine Oil on page 5-15.
I. Engine Cooling Fan. SeeCooling System on
page 5-28.
J. Power Steering Fluid Reservoir. SeePower Steering
Fluid on page 5-38.
K. Brake Master Cylinder Reservoir. See “Brake Fluid”
underBrakes on page 5-41.L.Underhood Fuse Block on page 5-120.
M. Windshield Washer Fluid Reservoir. See “Adding
Washer Fluid” underWindshield Washer Fluid
on page 5-39.
Engine Oil
Checking Engine Oil
It is a good idea to check the engine oil every time you
get fuel. In order to get an accurate reading, the oil
must be warm and the vehicle must be on level ground.
The engine oil dipstick handle is a yellow loop. See
Engine Compartment Overview on page 5-14for
the location of the engine oil dipstick.
1. Turn off the engine and give the oil several minutes
to drain back into the oil pan. If you do not do this,
the oil dipstick might not show the actual level.
2. Pull out the dipstick and clean it with a paper towel
or cloth, then push it back in all the way. Remove it
again, keeping the tip down, and check the level.
5-15