2010 GMC YUKON HYBRID warning

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
{WARNING:
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.
6-3

{WARNING:
Steam and scalding liquids from a hot cooling
system can blow out and burn you badly. They are
under pressure, and if you turn the coolant surge
tank pressure cap—even a little —they can come
out at high speed. Never turn the cap when the
cooling system, including the coolant surge tank
pressure cap, is hot. Wait for the cooling system
and coolant surge tank pressure cap to cool if you
ever have to turn the pressure cap.
Notice: Using coolant other than a pre‐mixed
DEX-COOL, available at your dealer/retailer, may
damage your vehicle. Any repairs would not be
covered by your warranty. Always use a pre‐mixed
DEX-COOL (silicate-free) coolant in your vehicle.
{WARNING:
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 , the vehicle must be
serviced by your dealer and a special fill procedure
must be followed.
Notice:
Attempting to fill the DMCM cooling surge
tank yourself when the fluid 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.
6-11

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

Only a trained service technician with the proper
knowledge and tools should inspect, test, or replace
the hybrid battery. See your dealer/retailer if the
hybrid battery needs service. The dealer/retailer
has information on how to recycle the hybrid
battery. There is also information available at
http://www.recyclemybattery.com.
If an airbag inflates or the vehicle has been in a crash,
the vehicle's sensing system might command the
automatic hybrid battery disconnect to open. See
Replacing Restraint System Parts After a Crash
on
page 2‑3for more information.
{DANGER:
Battery posts, terminals, and related accessories
contain lead and lead compounds, chemicals
known to the State of California to cause cancer
and reproductive harm. Wash hands after
handling.
Vehicle Storage
{WARNING:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you are
not careful. See Jump Starting
on page 6‑18
for tips on working around a battery without
getting hurt.
Infrequent Usage: Remove the 12‐volt battery black,
negative (−) cable from the battery to keep the battery
from running down.
Extended Storage: Remove the 12‐volt battery black,
negative (−) cable from the battery or use a battery
trickle charger.
Remember to reconnect the battery when ready to drive
the vehicle.
6-17

Jump Starting
{WARNING:
Personal injury, death, or damage to the vehicle
can result if you try jump starting or using a
battery charger on the high voltage hybrid battery.
Use only the 12-volt battery for jump starting and
charging.
If the vehicle's 12‐volt battery has run down, you may
want to use another vehicle and some jumper cables to
start your vehicle. Use the following steps to do it safely.
{WARNING:
Batteries can hurt you. They can be dangerous
because:
.They contain acid that can burn you.
.They contain gas that can explode or ignite.
.They contain enough electricity to burn you.
If you do not follow these steps exactly, some or
all of these things can hurt you.
Notice: Ignoring these steps could result in costly
damage to the vehicle that would not be covered by
the warranty.
Trying to start the vehicle by pushing or pulling it
will not work, and it could damage the vehicle.
1. Check the other vehicle. It must have a 12‐volt battery with a negative ground system.
Notice: If the other vehicle's system is not a 12-volt
system with a negative ground, both vehicles can
be damaged. Only use vehicles with 12-volt systems
with negative grounds to jump start your vehicle.
6-18

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