engine GMC YUKON HYBRID 2009 Owner's Manual

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

When you decide it is safe to lift the hood, here is what
you will see:
A. Drive Motor/Generator Control Module (DMCM)
B. Engine Coolant Surge Tank Pressure Cap
C. DMCM Coolant Surge Tank/Engine Coolant
Surge Tank
D. DMCM Cooling Hoses (Out of View)
E. DMCM Coolant Tank Pressure Cap
If the coolant inside the DMCM coolant surge tank is
boiling, do not do anything else until it cools down.The coolant level should be at or above the FULL
COLD mark with the vehicle parked on a level surface.
If it is not, there might be a leak at the DMCM cooler
core, DMCM pressure cap, DMCM cooler hoses,
DMCM cooling pump or somewhere else in the DMCM
cooling system.
Notice:Running the engine when there is a leak in
the hybrid cooling system can cause the hybrid
cooling system to lose all coolant and can damage
the system. Get any leak xed before you drive
the vehicle or run the engine.
5-7

{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.
5-9

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

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

Notice:If you leave the radio or other accessories
on during the jump starting procedure, they
could be damaged. The repairs would not be
covered by the warranty. Always turn off the radio
and other accessories when jump starting the
vehicle.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or the accessory power outlets. Turn off
the radio and all the lamps that are not needed.
This avoids sparks and helps save both batteries.
It could save the radio!
4. Open the hood on the other vehicle and locate the
positive (+) and negative (−) terminal locations on
that vehicle.
Your vehicle has a remote positive (+) and a remote
negative (−) jump starting terminal. You should
always use these remote terminals instead of the
terminals on the battery.If the vehicle has a remote positive (+), it is located
under a red plastic cover at the positive battery
post. To uncover the remote positive (+) terminal,
open the red plastic cover.
5. The remote negative (−) is a solid engine ground.
5-17

{CAUTION:
An electric fan can start up even when the engine
is not running and can injure you. Keep hands,
clothing and tools away from any underhood
electric fan.
{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing this,
and some have been blinded. Use a flashlight if
you need more light.
CAUTION: (Continued)
CAUTION: (Continued)
Be sure the battery has enough water. You do not
need to add water to the battery installed in your
new vehicle. But if a battery has filler caps, be
sure the right amount of fluid is there. If it is low,
add water to take care of that first. If you do not,
explosive gas could be present.
Battery fluid contains acid that can burn you.
Do not get it on you. If you accidentally get it in
your eyes or on your skin, flush the place with
water and get medical help immediately.
{CAUTION:
Fans or other moving engine parts can injure you
badly. Keep your hands away from moving parts
once the engine is running.
5-18

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