2009 GMC YUKON HYBRID brakes

Starting and Operating
Your Vehicle
Starting the Vehicle
{CAUTION:
Exiting the vehicle, without first shifting into
P (Park), may cause the vehicle to move, and you
or others can be seriously injured. Because the
vehicle has the Automatic Engine Start/Stop
feature, the vehicle’s engine might seem to be
shut off when you come to a complete stop.
CAUTION: (Continued)
CAUTION: (Continued)
However, once the brake pedal is released, the
vehicle can move. The vehicle’s engine can also
restart at any time.
Shift to P (Park) and turn the ignition to
LOCK/OFF, before exiting the vehicle.
Start the engine as you would any other engine.
See “Starting the Engine” in the owner manual for more
information on starting. The hybrid system provides
very quiet engine starting. If pulling a trailer with trailer
brakes, seeTowing a Trailer on page 4-2for more
information.
2-3

D (Drive):This position is for normal driving. It provides
the best fuel economy. If you need more power for
passing, and you are:
•Going less than about 35 mph (55 km/h), push the
accelerator pedal about halfway down.
•Going about 35 mph (55 km/h) or more, push the
accelerator all the way down.
D (Drive) or M (Manual Mode) can be used when towing
a trailer, carrying a heavy load, driving on steep hills,
or for off-road driving. You may want to shift the
transmission to a lower gear selection if the transmission
shifts too often.
Downshifting the transmission in slippery road conditions
could result in skidding. See “Skidding” under “Loss of
Control” in the Index of the vehicle’s owner manual
for more information.
When temperatures are very cold, the transmission’s
gear shifting may be delayed, providing more stable
shifts until the engine warms up. Shifts may be more
noticeable with a cold transmission. This difference
in shifting is normal.M (Manual Mode):This position lets drivers select
the range of gears appropriate for current driving
conditions. If the vehicle has this feature, see “Range
Selection Mode” later in this section.
Notice:Spinning the tires or holding the vehicle
in one place on a hill using only the accelerator
pedal may damage the transmission. The repair will
not be covered by the vehicle warranty. If you are
stuck, do not spin the tires. When stopping on a hill,
use the brakes to hold the vehicle in place.
The vehicle has a shift stabilization feature that
adjusts the transmission shifting to the current driving
conditions to reduce rapid upshifts and downshifts.
If the shift stabilization feature determines that a current
vehicle speed cannot be maintained, the transmission
does not upshift. In some cases, this may appear to be a
delayed shift, however the transmission is operating
normally.
2-8

Regenerative Braking
Regenerative braking is a hybrid technology that
enables the electric drive motor to operate as a
generator when coasting or braking. Energy from the
moving vehicle recharges the hybrid battery.
The hydraulic disc brakes work with the regenerative
braking to insure effective braking, such as when a high
braking demand is requested.
The braking system is computer controlled and blends
the regenerative braking with the conventional hydraulic
disc brakes to meet any requirements for deceleration.
The controller interprets the braking request and uses
regenerative braking, conventional hydraulic braking or
a combination of both as necessary. Because the
controller applies the hydraulic brakes through its high
pressure accumulator, you may occasionally hear
the motor driven pump when it recharges the system.
This is normal.
See “Warning Lights, Gages, and Indicators” and “Driver
Information Center (DIC)” in the Index of the owner
manual. In the event of a controller problem, the brake
pedal may be harder to push and the stopping
distance may be longer.
Running the Vehicle While Parked
It is better not to park with the engine running. But if you
ever have to, here are some things to know.
{CAUTION:
Exiting the vehicle, without first shifting into
P (Park), may cause the vehicle to move, and you
or others can be seriously injured. Because the
vehicle has the Automatic Engine Start/Stop
feature, the vehicle’s engine might seem to be
shut off when you come to a complete stop.
However, once the brake pedal is released, the
vehicle can move. The vehicle’s engine can also
restart at any time.
Shift to P (Park) and turn the ignition to
LOCK/OFF, before exiting the vehicle.
Follow the proper steps to be sure the vehicle will not
move. See “Shifting Into Park” in the owner manual
for more information.
If pulling a trailer, seeTowing a Trailer on page 4-2for
more information.
2-10

Antilock Brake System (ABS)
Warning Light
For vehicles with the
Antilock Brake System
(ABS), this light comes on
briefly when the engine
is in ON/RUN.
That is normal. If the light does not come on then, have
it fixed so it will be ready to warn if there is a problem.
If the ABS light stays on, turn the ignition off, if the light
comes on while driving, stop as soon as it is safely
possible and turn the ignition off. Then start the engine
again to reset the system. If the ABS light still stays
on, or comes on again while driving, the vehicle needs
service. If the regular brake system warning light is
not on, the vehicle still has brakes, but not antilock
brakes. If the regular brake system warning light is
also on, the vehicle does not have antilock brakes
and there is a problem with the regular brakes.
SeeBrake System Warning Light on page 3-6.
For vehicles with a Driver Information Center (DIC),
seeDIC Warnings and Messages on page 3-12for all
brake related DIC messages.
StabiliTrak®Indicator Light
For vehicles with
StabiliTrak, this warning
light comes on briefly when
the ignition is in ON/RUN.
If it does not, have the vehicle serviced by your
dealer/retailer. If the system is working normally the
indicator light goes off.
When this light flashes, the system is on.
If it stays on while driving, there may be a problem with
the StabiliTrak system and the vehicle may need
service. See the owner manual for more information.
3-7

SERVICE BATTERY CHARGING
SYSTEM
If the hybrid battery system faults or fails this message
will appear on the DIC. The engine auto stop feature
will be disabled and the battery/charging system light will
appear in the instrument panel cluster. See “Battery
Warning Light” in the owner manual Index.
Driving with this light on could drain your batteries.
Have the electrical system checked as soon as possible.
Pressing the select button or the trip odometer reset
stem on the instrument panel cluster will acknowledge
this message and clear it from the DIC display.
HOOD OPEN
If the hood is not fully closed or there is a problem
with the hood switch, this message will be displayed.
Close the hood to clear the message. If the HOOD
OPEN message continues to be displayed after
verifying the hood is closed, you should have the hood
switch serviced. Pressing the select button or the
trip odometer reset stem on the instrument panel cluster
will acknowledge this message and clear it from the
DIC display.
When this message is displayed, the auto stop
function will not operate. If the vehicle is in auto stop
mode when this message appears, the engine will
instantly start.
OIL PRESSURE LOW STOP ENGINE
If engine oil pressure is low, this message will be
displayed on the DIC. Stop the vehicle as soon as safely
possible and do not operate it until the cause of the
low oil pressure has been corrected. Check your oil level
as soon as possible and have your vehicle serviced.
See “Engine Oil” in the owner manual Index.
SERVICE BRAKE SYSTEM
This message will be displayed if there is a problem
with the brake system. You will still be able to brake, but
it will be noticeably more difficult. Pull off the road to a
safe location and have your vehicle towed to the nearest
dealer/retailer for service. See “Brakes,” “Brake System
Warning Light,” and “ABS Brake System Warning
Light” in the owner manual Index.
SERVICE HYBRID SYSTEM
If this message is displayed on the DIC, the vehicle may
continue to operate, but you need to have it serviced
as soon as possible.
SERVICE POWER STEERING
This message displays if a problem has been detected
with the electric power steering. Have your vehicle
serviced by your dealer/retailer immediately.
3-13

Maximum trailer weight is calculated assuming only the
driver is in the tow vehicle and it has all the required
trailering equipment. The weight of additional optional
equipment, passengers and cargo in the tow vehicle
must be subtracted from the maximum trailer weight.Use the following charts to determine how much the
vehicle can weigh, based upon the vehicle model
and options.
Vehicle Axle Ratio Maximum Trailer Weight GCWR*
2WD 6.0 L V8 3.08 6,200 lbs (2 812 kg) 12,000 lbs (5 443 kg)
4WD 6.0 L V8 3.08 6,000 lbs (2 722 kg) 12,000 lbs (5 443 kg)
*The Gross Combination Weight Rating (GCWR) is the total allowable weight of the completely loaded vehicle and
trailer including any passengers, cargo, equipment and conversions. The GCWR for the vehicle should not be
exceeded.
Trailer Brakes
If a trailer is being towed that has trailer brakes and
the trailer brakes are manually applied while driving
slower than 25 mph (40 km/h), the vehicle may go into
auto stop mode even if the brakes are not being
pressed. Using the trailer brake system manually can
make the hybrid vehicle perform as if the brake pedalin the vehicle is being pressed. The trailer brake
operation check will still work. If the trailer brakes are
manually applied for an extended period of time,
the SERVICE BRAKE SYSTEM DIC message comes
on. The message goes off after the trailer brakes
have been released. No other action is necessary.
For more information, see “Trailer Brakes” in the Index
of the vehicle’s owner manual.
4-3

Service............................................................5-2
Doing Your Own Service Work.........................5-2
Checking Things Under the Hood.....................5-3
High Voltage Devices and Wiring......................5-3
Engine Compartment Overview.........................5-4
Automatic Transmission Fluid...........................5-5
Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap..................5-6
Drive Motor/Generator Control Module (DMCM)
Cooling System...........................................5-6
Power Steering Fluid.....................................5-11
Brakes........................................................5-11
Battery........................................................5-15
Jump Starting...............................................5-16
Bulb Replacement..........................................5-21
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps.........................................5-21
Replacement Bulbs.......................................5-22Electrical System............................................5-22
Fuses and Circuit Breakers............................5-22
Underhood Fuse Block..................................5-22
Tires..............................................................5-24
Inflation - Tire Pressure.................................5-24
Tire Pressure Monitor Operation.....................5-25
Tire Inspection and Rotation...........................5-29
Tire Chains..................................................5-30
If a Tire Goes Flat........................................5-30
Tire Sealant and Compressor Kit
(Without Selector Switch)............................5-32
Tire Sealant and Compressor Kit
(With Selector Switch)................................5-42
Tire Sealant and Compressor Kit Storage.........5-50
Capacities and Specications..........................5-52
Section 5 Service and Appearance Care
5-1

A. See “Engine Air Cleaner/Filter” in the owner manual.
B. Drive Motor/Generator Control Module (DMCM).
SeeDrive Motor/Generator Control Module (DMCM)
Cooling System on page 5-6.
C. Engine Oil Dipstick. See “Engine Oil” in the owner
manual.
D. Automatic Transmission Fluid Dipstick. See
Automatic Transmission Fluid on page 5-5.
E. Brake Fluid Reservoir. SeeBrakes on page 5-11.
F. See “Underhood Fuse Block” in the owner manual.
G. See “Windshield Washer Fluid” in the owner
manual.
H. Hybrid Auxiliary Fuse Block. SeeUnderhood Fuse
Block on page 5-22.
I. DMCM Coolant Surge Tank Pressure Cap. See
Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap on page 5-6.
J. See “Coolant Surge Tank Pressure Cap” in
the owner manual.
K. Engine Oil Fill Cap. See “Engine Oil” in the owner
manual.Automatic Transmission Fluid
For more information, see “Automatic Transmission
Fluid” in the owner manual Index.
Checking the Fluid Level
Your vehicle’s automatic transmission dipstick looks like
this. For more information on location, seeEngine
Compartment Overview on page 5-4.
5-5