service GMC YUKON HYBRID 2009 User Guide

Service
Doing Your Own Service Work
{CAUTION:
Never try to do your own service on hybrid
components. You can be injured and the vehicle
can be damaged if you try to do your own service
work. Service and repair of these hybrid
components should only be performed by a
trained service technician with the proper
knowledge and tools.
{CAUTION:
You can be injured and the vehicle could be
damaged if you try to do service work on a vehicle
without knowing enough about it.
•Be sure you have sufficient knowledge,
experience, the proper replacement parts,
and tools before attempting any vehicle
maintenance task.
•Be sure to use the proper nuts, bolts, and
other fasteners. English and metric fasteners
can be easily confused. If the wrong fasteners
are used, parts can later break or fall off.
You could be hurt.
5-2

If doing some of your own service work, use the proper
service manual. It tells you much more about how to
service the vehicle than this manual can. To order
the proper service manual, see “Service Publications
Ordering Information” in the owner manual.
This vehicle has an airbag system. Before attempting
to do your own service work, see “Servicing Your
Airbag-Equipped Vehicle” in the owner manual.
Keep a record with all parts receipts and list the
mileage and the date of any service work performed.
See “Maintenance Record” in the owner manual.Checking Things Under
the Hood
High Voltage Devices and Wiring
{CAUTION:
Exposure to high voltage can cause shock, burns,
and even death. The high voltage systems in your
vehicle can only be serviced by technicians with
special training.
High voltage devices are identified by labels.
Do not remove, open, take apart, or modify these
devices. High voltage cable or wiring has orange
covering. Do not probe, tamper with, cut, or modify
high voltage cable or wiring.
5-3

Drive Motor/Generator Control
Module (DMCM) Coolant Surge Tank
Pressure Cap
SeeEngine Compartment
Overview on page 5-4
for more information
on location.
The Drive Motor/Generator Control Module (DMCM)
coolant surge tank pressure cap must be fully installed
on the hybrid coolant surge tank.
Notice:If the pressure cap is not tightly installed,
coolant loss and possible damage to the Drive
Motor/Generator Control Module (DMCM) may occur.
Be sure the cap is properly and tightly secured.
Drive Motor/Generator Control
Module (DMCM) Cooling System
In addition to the regular cooling system, the vehicle is
also equipped with a cooling system for the DMCM
system. This system is serviced differently than
the vehicle’s main cooling system. The DMCM cooling
system includes the DMCM coolant surge tank,
DMCM surge tank pressure cap, DMCM cooling pumps,
hybrid cooling radiator and the Drive Motor/Generator
Control Module (DMCM). The DMCM cooling system
uses a 50/50 pre-mixed DEX-COOL™ coolant and
deionized water available at your dealer/retailer.
See “Engine Coolant” and “Cooling System” in the
owner manual for more information.
5-6

{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains ethylene glycol
and it will burn if the engine parts are hot enough.
Do not spill coolant on a hot engine.
If the DMCM coolant is empty, your vehicle must be
serviced by your dealer and a special fill procedure
must be followed.
Notice:Attempting to ll the DMCM cooling surge
tank yourself when the uid level is empty can
damage your vehicle. Your vehicle must be serviced.1. Park the vehicle on a level surface and turn the
vehicle off. Remove the DMCM coolant surge
tank pressure cap when the DMCM cooling system,
including the DMCM coolant surge tank pressure
cap and DMCM cooling hoses, are no longer hot.
Turn the DMCM coolant surge tank pressure cap
slowly counterclockwise (left) about one full turn.
Wait 30 seconds.
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2. Then keep turning the DMCM coolant surge tank
pressure cap slowly, and remove it.
3. Add the pre-mixed DEX-COOL™, available at your
dealer/retailer, to the DMCM coolant surge tank
until the level reaches the FULL COLD mark.
4. Turn the ignition to ON/RUN without starting the
engine. The hybrid cooling pumps will run and
any trapped air will purge to the surge tank.5. Add the pre-mixed DEX-COOL™, available at your
dealer/retailer, until the coolant level is maintained
at the FULL COLD mark. This should take no
longer than two minutes of hybrid cooling pump
operation.
If the level cannot be kept at the FULL COLD
level, your vehicle may need service. See your
dealer/retailer.
6. Then replace the
DMCM coolant surge
tank pressure cap.
Be sure the pressure
cap is hand-tight
and fully seated.
Notice:Using tap water, cooling system sealers or
conditioners in an attempt to stop coolant leaks
can damage the DMCM and engine cooling systems.
Never use tap water, cooling system sealers or
conditioners in your cooling system.
5-10

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

6. Check that the jumper cables do not have loose
or missing insulation. If they do, you could get a
shock. The vehicles could be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+) goes to
positive (+) or to a remote positive (+) terminal
if the vehicle has one. Negative (−) will go to
a heavy, unpainted metal engine part or a solid
engine ground.
Do not connect positive (+) to negative (−)oryou
will get a short that would damage the battery
and maybe other parts too. Do not connect
the negative (−) cable to the negative (−) terminal
on the dead battery because this can cause sparks.
7. Connect the red positive (+) cable to the positive (+)
terminal of the vehicle with the dead battery.
Use a remote positive (+) if the vehicle has one.8. Do not let the other end touch metal. Connect it
to the positive (+) terminal of the good battery.
Use a remote positive (+) if the vehicle has one.
9. Now connect the black negative (−) cable to the
negative (−) terminal of the good battery. Use a
remote negative (−) if the vehicle has one.
Do not let the other end touch anything until the
next step. The other end of the negative (−) cable
does not go to the dead battery. It goes to a
heavy, unpainted metal engine part or to the remote
negative (−) terminal on the vehicle with the dead
battery.
10. Connect the other end of the negative (−) cable to
the remote negative (−) terminal, on the vehicle
with the dead battery.
11. Now start the vehicle with the good battery and run
the engine for a while.
12. Try to start the vehicle that had the dead battery.
If it will not start after a few tries, it probably needs
service.
5-19

Replacement Bulbs
Exterior Lamp Bulb Number
Back-up Lamp and Rear Turn
Signal Lamp3156
Sidemarker Lamp 194
For replacement bulbs not listed here, contact your
dealer/retailer.
Electrical System
Fuses and Circuit Breakers
The wiring circuits in the vehicle are protected from
short circuits by a combination of fuses, circuit breakers
and fusible thermal links. This greatly reduces the
chance of fires caused by electrical problems.
Be sure you replace a bad fuse with a new one of the
identical size and rating.If you ever have a problem on the road and do not have
a spare fuse, you can borrow one that has the same
amperage. Just pick some feature of the vehicle that you
can get along without, like the radio or cigarette
lighter, and use its fuse, if it is the correct amperage.
Replace it as soon as you can.
The vehicle also has a special fuse in the battery box
for the 300-volt batteries. If this fuse has failed and
needs to be replaced, the vehicle will be disabled and
you will need to have the vehicle repaired by your
dealer/retailer. Do not attempt to self-service this fuse.
Underhood Fuse Block
Hybrid Auxiliary Underhood Fuse
Block
The hybrid underhood fuse block is located in the
engine compartment near the front of the vehicle.
Lift the cover for access to the fuse/relay block.
SeeEngine Compartment Overview on page 5-4for
more information on its location. For more information on
the main underhood fuse block, see “Underhood Fuse
Block” in the owner manual.
5-22

•One or more TPMS sensors are missing or
damaged. The DIC message and the TPMS
malfunction light should go off when the TPMS
sensors are installed and the sensor matching
process is performed successfully. See your
dealer/retailer for service.
•Replacement tires or wheels do not match your
vehicle’s original equipment tires or wheels.
Tires and wheels other than those recommended
for your vehicle could prevent the TPMS from
functioning properly. See “Buying New Tires” in
the Index of the owner manual.
•Operating electronic devices or being near facilities
using radio wave frequencies similar to the TPMS
could cause the TPMS sensors to malfunction.
If the TPMS is not functioning it cannot detect or
signal a low tire condition. See your dealer/retailer for
service if the TPMS malfunction light and DIC message
comes on and stays on.
TPMS Sensor Matching Process
Each TPMS sensor has a unique identification code.
Any time you rotate your vehicle’s tires or replace one or
more of the TPMS sensors, the identification codes
will need to be matched to the new tire/wheel position.
The sensors are matched to the tire/wheel positions
in the following order: driver side front tire, passenger
side front tire, passenger side rear tire, and driver
side rear tire using a TPMS diagnostic tool. See your
dealer/retailer for service.
The TPMS sensors can also be matched to each
tire/wheel position by increasing or decreasing the tire’s
air pressure. If increasing the tire’s air pressure, do
not exceed the maximum inflation pressure indicated on
the tire’s sidewall.
To decrease air-pressure out of a tire you can use the
pointed end of the valve cap, a pencil-style air pressure
gage, or a key.
5-27