2012 GMC YUKON overheating

Black plate (17,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-17
SeeEngine Overheating on
page 10‑21.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Voltmeter Gauge
When the engine is not running, but
the ignition is on, this gauge shows
the battery's state of charge in
DC volts. When the engine is running, the
gauge shows the condition of the
charging system. The charging
system regulates voltage based on
the state of the battery for improved
fuel economy and battery life. The
gauge may transition from a higher
to lower or a lower to higher
reading, this is normal. Readings
between the low and high warning
zones indicate the normal operating
range. The gauge may also read
low during the fuel economy mode,
this is normal.
Readings in the low warning zone
may occur when a large number of
electrical accessories are operating
in the vehicle and the engine is left
at an idle for an extended period.
This condition is normal since the
charging system is not able to
provide full power at engine idle. As
engine speeds are increased, this
condition should correct itself as
higher engine speeds allow the
charging system to create full
power. If there is a problem with the
battery charging system, this lightwill come on or the SERVICE
BATTERY CHARGING SYSTEM
DIC message will display. See
Battery Voltage and Charging
Messages on page 5‑38
and
Charging System Light on
page 5‑20 for more information.
Safety Belt Reminders
Driver Safety Belt Reminder
Light
There is a driver safety belt
reminder light on the instrument
panel cluster.
When the vehicle is started, this
light flashes and a chime may come
on to remind the driver to fasten
their safety belt. Then the light stays
on solid until the belt is buckled.

Black plate (40,1)GMC Yukon/Yukon XL Owner Manual - 2012
5-40 Instruments and Controls
If this message continues to appear,
have the system repaired by your
dealer as soon as possible to avoid
damage to the engine.
ENGINE OVERHEATED IDLE
ENGINE
Notice:If you drive the vehicle
while the engine is overheating,
severe engine damage may
occur. If an overheat warning
appears on the instrument panel
cluster and/or DIC, stop the
vehicle as soon as possible. See
Engine Overheating on
page 10‑21 for more information.
This message displays when the
engine coolant temperature is too
hot. Stop and allow the vehicle to
idle until it cools down. See Engine
Coolant Temperature Gauge on
page 5‑16.
See Overheated Engine Protection
Operating Mode on page 10‑23 for
information on driving to a safe
place in an emergency.
ENGINE OVERHEATED STOP
ENGINE
Notice: If you drive the vehicle
while the engine is overheating,
severe engine damage may
occur. If an overheat warning
appears on the instrument panel
cluster and/or DIC, stop the
vehicle as soon as possible. See
Engine Overheating on
page 10‑21 for more information.
This message displays and a chime
sounds if the engine cooling system
reaches unsafe temperatures for
operation. Stop and turn off the
vehicle as soon as it is safe to do so
to avoid severe damage. This
message clears when the engine
has cooled to a safe operating
temperature.
Engine Oil Messages
CHANGE ENGINE OIL SOON
This message displays when the
engine oil needs to be changed.
When you change the engine oil, be sure to reset the CHANGE ENGINE
OIL SOON message. See
Engine
Oil Life System on page 10‑10 for
information on how to reset the
message. See Engine Oil on
page 10‑8 andMaintenance
Schedule on page 11‑3 for more
information.
ENGINE OIL HOT IDLE
ENGINE
This message displays when the
engine oil becomes hotter than the
normal operating temperature. Stop
and allow the vehicle to idle until it
cools down. See Engine Coolant
Temperature Gauge on page 5‑16.
OIL PRESSURE LOW STOP
ENGINE
Notice: If you drive the vehicle
while the engine oil pressure is
low, severe engine damage may
occur. If a low oil pressure
warning appears on the Driver
Information Center (DIC), stop the
vehicle as soon as possible. Do
not drive the vehicle until the

Black plate (41,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-41
cause of the low oil pressure is
corrected. SeeEngine Oil on
page 10‑8 for more information.
This message displays if low oil
pressure levels occur. Stop the
vehicle as soon as safely possible
and do not operate it until the cause
of the low oil pressure has been
corrected. Check the oil as soon as
possible and have the vehicle
serviced by your dealer. See Engine
Oil on page 10‑8.
Engine Power Messages
ENGINE POWER IS REDUCED
This message displays and a chime
sounds when the cooling system
temperature gets too hot and the
engine further enters the engine
coolant protection mode. See
Engine Overheating on page 10‑21
for further information.
This message also displays when
the engine power is reduced.
Reduced engine power can affect
the vehicle's ability to accelerate. If this message is on, but there
is no reduction in performance,
proceed to your destination. The
performance may be reduced the
next time the vehicle is driven. The
vehicle may be driven at a reduced
speed while this message is on, but
acceleration and speed may be
reduced. Anytime this message
stays on, the vehicle should be
taken to your dealer for service as
soon as possible.
Fuel System Messages
FUEL LEVEL LOW
This message displays and a chime
sounds if the fuel level is low. Refuel
as soon as possible. See
Fuel
Gauge on page 5‑14 andFuel on
page 9‑61 for more information.
TIGHTEN GAS CAP
This message may display along
with the check engine light on the
instrument panel cluster if the fuel cap is not tightened properly. See
Malfunction Indicator Lamp on
page 5‑21. Reinstall the fuel cap
fully. See
Filling the Tank on
page 9‑65. The diagnostic system
can determine if the fuel cap has
been left off or improperly installed.
A loose or missing fuel cap allows
fuel to evaporate into the
atmosphere. A few driving trips with
the cap properly installed should
turn this light and message off.
Key and Lock Messages
REPLACE BATTERY IN
REMOTE KEY
This message displays if a Remote
Keyless Entry (RKE) transmitter
battery is low. The battery needs to
be replaced in the transmitter. See
“Battery Replacement” under
Remote Keyless Entry (RKE)
System Operation on page 2‑3.

Black plate (44,1)GMC Yukon/Yukon XL Owner Manual - 2012
5-44 Instruments and Controls
page 9‑15. To turn the StabiliTrak
system on or off, seeStabiliTrak®
System on page 9‑46.
STABILITRAK OFF may also
display when the stability control
has been automatically disabled.
There are several conditions that
can cause this message to appear.
.One condition is overheating,
which could occur if StabiliTrak
activates continuously for an
extended period of time.
.The message also displays if the
brake system warning light is on.
SeeBrake System Warning
Light on page 5‑23.
.The message could display if the
stability system takes longer
than usual to complete its
diagnostic checks due to driving
conditions.
.The message displays if an
engine or vehicle related
problem has been detected and
the vehicle needs service. See
your dealer. The message turns off as soon as
the conditions that caused the
message to be displayed are no
longer present.
Airbag System Messages
SERVICE AIR BAG
This message displays if there is a
problem with the airbag system.
Have your dealer inspect the
system for problems. See
Airbag
Readiness Light on page 5‑18 and
Airbag System on page 3‑30 for
more information.
Anti-theft Alarm System
Messages
SERVICE THEFT DETERRENT
SYSTEM
This message displays when there
is a problem with the theft-deterrent
system. The vehicle may or may not
restart so you may want to take the
vehicle to your dealer before turning off the engine. See
Immobilizer
Operation on page 2‑15 for more
information.
Tire Messages
SERVICE TIRE MONITOR
SYSTEM
On vehicles with the Tire Pressure
Monitor System (TPMS), this
message displays if a part on the
TPMS is not working properly. The
tire pressure light also flashes and
then remains on during the same
ignition cycle. See Tire Pressure
Light on page 5‑26. Several
conditions may cause this message
to appear. See Tire Pressure
Monitor Operation on page 10‑59 for
more information. If the warning
comes on and stays on, there may
be a problem with the TPMS. See
your dealer.
TIRE LEARNING ACTIVE
On vehicles with the Tire Pressure
Monitor System (TPMS), this
message displays when the TPMS

Black plate (45,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-45
is re-learning the tire positions on
your vehicle. The tire positions must
be re-learned after rotating the tires
or after replacing a tire or sensor.
SeeTire Inspection on page 10‑62,
Tire Rotation on page 10‑62, Tire
Pressure Monitor System on
page 10‑58, and Tire Pressure on
page 10‑56 for more information.
TIRE LOW ADD AIR TO TIRE
On vehicles with the Tire Pressure
Monitor System (TPMS), this
message displays when the
pressure in one or more of the
vehicle's tires needs to be checked.
This message also displays LEFT
FRT (left front), RIGHT FRT (right
front), LEFT RR (left rear),
or RIGHT RR (right rear) to indicate
the location of the low tire. The low
tire pressure warning light will also
come on. See Tire Pressure Light
on page 5‑26. You can receive more
than one tire pressure message at a
time. To read the other messages
that may have been sent at the same time, press the set/reset
button or the trip odometer reset
stem. If a tire pressure message
appears on the DIC, stop as soon
as you can. Have the tire pressures
checked and set to those shown on
the Tire Loading Information label.
See
Tires on page 10‑48, Vehicle
Load Limits on page 9‑16, and Tire
Pressure on page 10‑56. The DIC
also shows the tire pressure values.
See “DIC Operation and Displays
(With DIC Buttons)” earlier in this
section.
Transmission Messages
SERVICE 4 WHEEL DRIVE
This message displays if a problem
occurs with the four-wheel-drive
system. If this message appears,
stop as soon as possible and turn
off the vehicle. Make sure the key is
in the LOCK/OFF position for at
least one minute and then restart
the vehicle and check for the
message on the DIC display. If the message is still displayed or
appears again when you begin
driving, the four-wheel-drive system
needs service. See your dealer.
TRANSMISSION HOT IDLE
ENGINE
Notice:
If you drive the vehicle
while the transmission fluid is
overheating and the transmission
temperature warning is displayed
on the instrument panel cluster
and/or DIC, you can damage the
transmission. This could lead to
costly repairs that would not be
covered by the warranty. Do not
drive the vehicle with overheated
transmission fluid or while the
transmission temperature
warning is displayed.
This message displays along with a
sound if the transmission fluid in the
vehicle gets hot. Driving with the
transmission fluid temperature high
can cause damage to the vehicle.
Stop the vehicle and let it idle to
allow the transmission to cool.

Black plate (70,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-70 Driving and Operating
Making Turns
Notice:Making very sharp turns
while trailering could cause the
trailer to come in contact with the
vehicle. The vehicle could be
damaged. Avoid making very
sharp turns while trailering.
When turning with a trailer, make
wider turns than normal. Do this
so the trailer will not strike soft
shoulders, curbs, road signs, trees
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance.
If the trailer turn signal bulbs burn
out, the arrows on the instrument
panel will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Driving on Grades
Reduce speed and shift to a lower
gear before starting down a long or
steep downgrade. If the transmission is not shifted down, the
brakes might get hot and no longer
work well.
Vehicles can tow in D (Drive). Shift
the transmission to a lower gear if
the transmission shifts too often
under heavy loads and/or hilly
conditions.
The tow/haul mode may be used if
the transmission shifts too often.
See
Tow/Haul Mode Light on
page 5‑25.
When towing at high altitude on
steep uphill grades, consider the
following: Engine coolant will boil at
a lower temperature than at normal
altitudes. If the engine is turned off
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
automatic transmission in P (Park)
for a few minutes before turning the engine off. If the overheat warning
comes on, see
Engine Overheating
on page 10‑21.
Parking on Hills
{WARNING
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface.
If parking the rig on a hill:
1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks under the trailer wheels.

Black plate (1,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-3
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-4
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil . . . . . . . . . . . . . . . . . . . 10-8
Engine Oil Life System . . . . . 10-10
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-12
Engine Air Cleaner/Filter . . . . 10-15
Cooling System . . . . . . . . . . . . 10-16
Engine Coolant . . . . . . . . . . . . . 10-17 Engine Overheating . . . . . . . . 10-21
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-23
Engine Fan . . . . . . . . . . . . . . . . . 10-23
Power Steering Fluid . . . . . . . 10-24
Washer Fluid . . . . . . . . . . . . . . . 10-25
Brakes . . . . . . . . . . . . . . . . . . . . . 10-26
Brake Fluid . . . . . . . . . . . . . . . . . 10-27
Battery . . . . . . . . . . . . . . . . . . . . . 10-28
Four-Wheel Drive . . . . . . . . . . . 10-29
Front Axle . . . . . . . . . . . . . . . . . . 10-30
Rear Axle . . . . . . . . . . . . . . . . . . 10-31
Starter Switch Check . . . . . . . 10-32
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-32
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-33
Park Brake and P (Park) Mechanism Check . . . . . . . . 10-33
Wiper Blade Replacement . . . . . . . . . . . . . . 10-33
Glass Replacement . . . . . . . . 10-34
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-35
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-37
Halogen Bulbs . . . . . . . . . . . . . . 10-37
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-37
License Plate Lamp . . . . . . . . 10-38
Replacement Bulbs . . . . . . . . . 10-39
Electrical System
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-39
Fuses and Circuit Breakers . . . . . . . . . . . . . . . . . . 10-40
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-41
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . . . 10-45
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . 10-48
Tire Sidewall Labeling . . . . . . 10-50
Tire Designations . . . . . . . . . . . 10-52
Tire Terminology and
Definitions . . . . . . . . . . . . . . . . 10-53
Tire Pressure . . . . . . . . . . . . . . . 10-56
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . 10-58

Black plate (17,1)GMC Yukon/Yukon XL Owner Manual - 2012
Vehicle Care 10-17
{WARNING
An electric engine cooling fan
under the hood can start up even
when the engine is not running
and can cause injury. Keep
hands, clothing, and tools away
from any underhood electric fan.
{WARNING
Heater and radiator hoses, and
other engine parts, can be very
hot. Do not touch them. If you do,
you can be burned.(Continued)
WARNING (Continued)
Do not run the engine if there is a
leak. If you run the engine, it
could lose all coolant. That could
cause an engine fire, and you
could be burned. Get any leak
fixed before you drive the vehicle.
Notice: Using coolant other than
DEX-COOL
®can cause premature
engine, heater core, or radiator
corrosion. In addition, the engine
coolant could require changing
sooner, at 50 000 km (30,000 mi)
or 24 months, whichever occurs
first. Any repairs would not be
covered by the vehicle warranty.
Always use DEX-COOL
(silicate-free) coolant in the
vehicle.
Engine Coolant
The cooling system in the vehicle
is filled with DEX-COOL engine
coolant. This coolant is designed to
remain in the vehicle for 5 years or
240 000 km (150,000 mi), whichever
occurs first.
The following explains the cooling
system and how to check and add
coolant when it is low. If there is a
problem with engine overheating,
see Engine Overheating on
page 10‑21.