engine GMC YUKON HYBRID 2010 Service Manual

Turn the DMCM coolant surge tank pressure cap
slowly counterclockwise (left) about one full turn.
Wait 30 seconds.
2. Then keep turning the DMCM coolant surge tankpressure 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.
6-12

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 6‑4for 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.
{WARNING:
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.
6-13

Checking Brake Fluid
Check brake fluid by looking at the brake fluid reservoir.
SeeEngine Compartment Overview on page 6‑4.
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.
{WARNING:
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.
6-14

Notice:
.Using the wrong fluid 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 fluid.
.If brake fluid is spilled on the vehicle's
painted surfaces, the paint finish can be
damaged. Be careful not to spill brake fluid
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.
{WARNING:
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.
6-15

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.
{WARNING:
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.
{WARNING:
Using an open flame 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.
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. (Continued)
6-20

WARNING: (Continued)
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.
{WARNING:
Fans or other moving engine parts can injure you
badly. Keep your hands away from moving parts
once the engine is running.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 (−) or you
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.
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8. Do not let the other end touch metal. Connect it tothe 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.
Notice: If the jumper cables are connected or
removed in the wrong order, electrical shorting may
occur and damage the vehicle. The repairs would
not be covered by the vehicle warranty. Always
connect and remove the jumper cables in the
correct order, making sure that the cables do not
touch each other or other metal.
6-22

Jumper Cable Removal
A. Heavy, Unpainted Metal Engine Part or RemoteNegative (−) Terminal
B. Good Battery or Remote Positive (+) and Remote Negative (−) Terminals
C. Dead Battery or Remote Positive (+) Terminal To disconnect the jumper cables from both vehicles:
1. Disconnect the black negative (−) cable from the vehicle that had the bad battery.
2. Disconnect the black negative (−) cable from the vehicle with the good battery.
3. Disconnect the red positive (+) cable from the vehicle with the good battery.
4. Disconnect the red positive (+) cable from the other vehicle.
5. Return the remote positive (+) terminal cover to its original position.
6-23

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 6‑4for more
information on its location. For more information on the
main underhood fuse block, see “Underhood Fuse
Block” in the owner manual.
6-26

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.
You have two minutes to match the first tire/wheel
position, and five minutes overall to match all four
tire/wheel positions. If it takes longer than two minutes,
to match the first tire and wheel, or more than
five minutes to match all four tire and wheel positions
the matching process stops and you need to start over.The TPMS sensor matching process is outlined below:
1. Set the parking brake.
2. Turn the ignition switch to ON/RUN with the engine off.
3. Press
QandKon the Remote Keyless Entry
(RKE) transmitter at the same time for
approximately five seconds. The horn sounds
twice to signal the receiver is in relearn mode and
TIRE LEARNING ACTIVE message displays on
the DIC screen.
4. Start with the driver side front tire.
5. Remove the valve cap from the valve cap stem. Activate the TPMS sensor by increasing or
decreasing the tire's air pressure for five seconds,
or until a horn chirp sounds. The horn chirp, which
may take up to 30 seconds to sound, confirms that
the sensor identification code has been matched to
this tire and wheel position.
6. Proceed to the passenger side front tire, and repeat the procedure in Step 5.
7. Proceed to the passenger side rear tire, and repeat the procedure in Step 5.
6-32