2009 GMC YUKON HYBRID brakes

Power Steering Fluid
The vehicle has electric power steering and does not
use power steering fluid.
Brakes
Brake Fluid
The brake master cylinder
reservoir is filled with
DOT-3 brake fluid. See
Engine Compartment
Overview on page 5-4
for the location of
the reservoir.
There are only two reasons why the brake fluid level in
the reservoir might go down:
•The brake fluid level goes down because of normal
brake lining wear. When new linings are installed,
the fluid level goes back up.
•A fluid leak in the brake hydraulic system can also
cause a low fluid level. Have the brake hydraulic
system fixed, since a leak means that sooner
or later the brakes will not work well.Do not top off the brake fluid. Adding fluid does not
correct a leak. If fluid is added when the linings
are worn, there will be too much fluid when new brake
linings are installed. Add or remove brake fluid, as
necessary, only when work is done on the brake
hydraulic system.
{CAUTION:
If too much brake fluid is added, it can spill on
the engine and burn, if the engine is hot enough.
You or others could be burned, and the vehicle
could be damaged. Add brake fluid only when
work is done on the brake hydraulic system.
See “Checking Brake Fluid” in this section.
When the brake fluid falls to a low level, the brake
warning light comes on. See “Brake System Warning
Light” in the owner manual.
Refer to the Maintenance Schedule to determine when
to check the brake fluid. See “Scheduled Maintenance”
in the owner manual.
5-11

Checking Brake Fluid
Check brake fluid by looking at the brake fluid reservoir.
SeeEngine Compartment Overview on page 5-4.
With the engine not running for at least one minute, the
maximum fluid level (A) is at the top of the reservoir
body. With the engine running, the fluid level should be
in the proper operating range (B) between the MIN
and MAX marks. If it is not, have the brake hydraulic
system checked to see if there is a leak.After work is done on the brake hydraulic system,
make sure the level, with the engine running, is in
the proper operating range (B) between the MIN and
MAX marks.
What to Add
Use only new DOT-3 brake fluid from a sealed
container. See “Recommended Fluids and Lubricants”
in the owner manual.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This helps keep
dirt from entering the reservoir.
{CAUTION:
With the wrong kind of fluid in the brake hydraulic
system, the brakes might not work well. This could
cause a crash. Always use the proper brake fluid.
5-12

Notice:
Using the wrong uid can badly damage brake
hydraulic system parts. For example, just a
few drops of mineral-based oil, such as engine
oil, in the brake hydraulic system can damage
brake hydraulic system parts so badly that they
will have to be replaced. Do not let someone
put in the wrong kind of uid.
If brake uid is spilled on the vehicle’s painted
surfaces, the paint nish can be damaged.
Be careful not to spill brake uid on the
vehicle. If you do, wash it off immediately.
See “Washing Your Vehicle” in the owner
manual.
Brake Wear
This vehicle has disc brakes. Disc brake pads have
built-in wear indicators that make a high-pitched warning
sound when the brake pads are worn and new pads
are needed. The sound can come and go or be heard all
the time the vehicle is moving, except when applying
the brake pedal firmly.
{CAUTION:
The brake wear warning sound means that soon
the brakes will not work well. That could lead to an
accident. When the brake wear warning sound is
heard, have the vehicle serviced.
Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates can cause a brake
squeal when the brakes are first applied or lightly
applied. This does not mean something is wrong with
the brakes.
5-13

Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to torque specifications in
“Capacities and Specifications” in the owner manual.
Brake linings should always be replaced as complete
axle sets.
Brake Pedal Travel
See your dealer/retailer if the brake pedal does not
return to normal height, or if there is a rapid increase in
pedal travel. This could be a sign that brake service
might be required.
Brake Adjustment
Every time the brakes are applied, the disc brakes
adjust for wear.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its many
parts have to be of top quality and work well together
if the vehicle is to have really good braking. The
vehicle was designed and tested with top-quality
brake parts. When parts of the braking system are
replaced — for example, when the brake linings wear
down and new ones are installed — be sure to get new
approved replacement parts. If this is not done, the
brakes might not work properly. For example, if
someone puts in brake linings that are wrong for the
vehicle, the balance between the front and rear brakes
can change — for the worse. The braking performance
expected can change in many other ways if the
wrong replacement brake parts are installed.
5-14

Tire Chains
{CAUTION:
Do not use tire chains. There is not enough
clearance. Tire chains used on a vehicle without
the proper amount of clearance can cause
damage to the brakes, suspension, or other
vehicle parts. The area damaged by the tire
chains could cause you to lose control of the
vehicle and you or others may be injured in a
crash. Use another type of traction device only if
its manufacturer recommends it for use on the
vehicle and tire size combination and road
conditions. Follow that manufacturer’s instructions.
To help avoid damage to the vehicle, drive slowly,
re-adjust or remove the device if it is contacting
the vehicle, and do not spin the wheels. If you do
find traction devices that will fit, install them on the
rear tires.
If a Tire Goes Flat
Your vehicle has a tire inflator kit. There is no spare tire,
no tire changing equipment, and no place to store a tire.
It is unusual for a tire to blow out while you are driving,
especially if you maintain your tires properly. If air
goes out of a tire, it is much more likely to leak out
slowly. But, if you should ever have a blow out, here are
a few tips about what to expect and what to do:
If a front tire fails, the flat tire creates a drag that pulls
the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
5-30

A
Alternating Current
Power Outlet................................................ 2-2
Antilock Brake, System Warning Light.................. 3-7
Audio System(s)
Navigation/Radio System..............................3-14
Automatic Transmission, Fluid............................ 5-5
B
Battery..........................................................5-15
Brake Fluid....................................................5-11
Brakes..........................................................5-11
Regenerative Braking...................................2-10
System Warning Light.................................... 3-6
Bulb Replacement
Taillamps, Turn Signal, Stoplamps and
Back-up Lamps........................................5-21
C
Canadian Owners................................................ ii
Capacities and Specifications............................5-52
Chains, Tire...................................................5-30
Charging System Light...................................... 3-4Climate Controls............................................... 3-2
Compressor Kit
Storing.......................................................5-50
Compressor Kit, Tire Sealant....................5-32, 5-42
Coolant
Engine Temperature Gage.............................. 3-8
Coolant Surge Tank Pressure Cap, (DMCM)......... 5-6
Cooling System, (DMCM).................................. 5-6
D
Drive Motor/Generator Control Module (DMCM)
Coolant Surge Tank Pressure Cap................... 5-6
Drive Motor/Generator Control Module (DMCM)
Cooling System............................................. 5-6
Driver Information Center (DIC).........................3-12
Warnings and Messages...............................3-12
E
Engine
Compartment Overview.................................. 5-4
Coolant Temperature Gage............................. 3-8
Drive Belt Routing......................................... 6-2
1