2012 GMC YUKON maintenance

Black plate (21,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-21
Malfunction
Indicator Lamp
A computer system called OBD II
(On-Board Diagnostics-Second
Generation) monitors the operation
of the vehicle to ensure emissions
are at acceptable levels, to produce
a cleaner environment. This light
comes on when the vehicle is
placed in ON/RUN, as a check to
show it is working. If it does not,
have the vehicle serviced by your
dealer. SeeIgnition Positions on
page 9‑22 for more information.
If the malfunction indicator lamp
comes on and stays on while the
engine is running, this indicates that
there is an OBD II problem and
service is required.
Malfunctions often are indicated by
the system before any problem is
apparent. Being aware of the light
can prevent more serious damage
to the vehicle. This system assists
the service technician in correctly
diagnosing any malfunction.
Notice:If the vehicle is
continually driven with this light
on, the emission controls might
not work as well, the vehicle fuel
economy might not be as good,
and the engine might not run as
smoothly. This could lead to
costly repairs that might not be
covered by the vehicle warranty. Notice:
Modifications made to the
engine, transmission, exhaust,
intake, or fuel system of the
vehicle or the replacement of the
original tires with other than
those of the same Tire
Performance Criteria (TPC) can
affect the vehicle's emission
controls and can cause this light
to come on. Modifications to
these systems could lead to
costly repairs not covered by the
vehicle warranty. This could also
result in a failure to pass a
required Emission Inspection/
Maintenance test. See
Accessories and Modifications on
page 10‑3.
This light comes on during a
malfunction in one of two ways:
Light Flashing: A misfire condition
has been detected. A misfire
increases vehicle emissions and
could damage the emission control
system on the vehicle. Diagnosis
and service might be required.

Black plate (23,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-23
Emissions Inspection and
Maintenance Programs
Some local governments may have
programs to inspect the on-vehicle
emission control equipment. For the
inspection, the emission system test
equipment is connected to the
vehicle’s Data Link
Connector (DLC).
The DLC is under the instrument
panel to the left of the steering
wheel. See your dealer if assistance
is needed.
The vehicle may not pass
inspection if:
.The malfunction indicator lamp is
on with the engine running, or if
the light does not come on when
the ignition is turned to ON/RUNwhile the engine is off. See your
dealer for assistance in verifying
proper operation of the
malfunction indicator lamp.
.The OBD II (On-Board
Diagnostics) system determines
that critical emission control
systems have not been
completely diagnosed. The
vehicle would be considered not
ready for inspection. This can
happen if the 12-volt battery has
recently been replaced or run
down. The diagnostic system is
designed to evaluate critical
emission control systems during
normal driving. This can take
several days of routine driving.
If this has been done and the
vehicle still does not pass the
inspection for lack of OBD II
system readiness, your dealer
can prepare the vehicle for
inspection.
Brake System Warning
Light
With the ignition on, the brake
system warning light comes on
when the parking brake is set. If the
vehicle is driven with the parking
brake engaged, a chime sounds
when the vehicle speed is greater
than 8 km/h (5 mph).
The vehicle brake system consists
of two hydraulic circuits. If one
circuit is not working, the remaining
circuit can still work to stop the
vehicle. For normal braking
performance, both circuits need to
be working.
If the warning light comes on and a
chime sounds there could be a
brake problem. Have the brake
system inspected right away.

Black plate (27,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-27
Engine Oil Pressure Light
{WARNING
Do not keep driving if the oil
pressure is low. The engine can
become so hot that it catches fire.
Someone could be burned. Check
the oil as soon as possible and
have the vehicle serviced.
Notice: Lack of proper engine oil
maintenance can damage the
engine. The repairs would not be
covered by the vehicle warranty.
Always follow the maintenance
schedule for changing engine oil.
This light comes on briefly while
starting the engine. If it does not,
have the vehicle serviced by your dealer. If the system is working
normally the indicator light then
goes off.
If the light comes on and stays on, it
means that oil is not flowing through
the engine properly. The vehicle
could be low on oil and it might
have some other system problem.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Low Fuel Warning Light
This light, under the fuel gauge,
comes on briefly while the engine is
being started.
This light and a chime come on
when the fuel tank is low on fuel.
The Driver Information Center also
displays a FUEL LEVEL LOW
message. See
Fuel System
Messages on page 5‑41 for more
information. When fuel is added this
light and message should go off.
If they do not, have the vehicle
serviced by your dealer.
Security Light
The security light should come on
briefly as the engine is started. If the
system is working normally, the
indicator light turns off. If it does not
come on, have the vehicle serviced
by your dealer.
If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent
system.

Black plate (33,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-33
engine oil life system monitoring the
oil life, additional maintenance is
recommended in the Maintenance
Schedule in this manual. See
Maintenance Schedule on
page 11‑3for more information.
Remember, you must reset the OIL
LIFE display yourself after each oil
change. It will not reset itself. Also,
be careful not to reset the OIL LIFE
display accidentally at any time
other than when the oil has just
been changed. It cannot be reset
accurately until the next oil change.
To reset the engine oil life system,
see Engine Oil Life System on
page 10‑10.
Side Blind Zone Alert
If your vehicle has the Side Blind
Zone Alert (SBZA) system, this
display allows the system to be
turned on or off. Once in this
display, press the set/reset button to
select between ON or OFF. If you
choose ON, the system will be
turned on. If you choose OFF, the
system will be turned off. When the SBZA system is turned off, the DIC
will display the SIDE BLIND ZONE
ALERT SYSTEM OFF message as
a reminder that the system has
been turned off. See
Object
Detection System Messages on
page 5‑42 andSide Blind Zone Alert
(SBZA) on page 9‑54 for more
information.
Units
Press the vehicle information button
until UNITS displays. This display
allows you to select between metric
or English units of measurement.
Once in this display, press the set/
reset button to select between
METRIC or units ENGLISH. All of
the vehicle information will then be
displayed in the unit of
measurement selected.
Tire Pressure
On vehicles with the Tire Pressure
Monitor System (TPMS), the
pressure for each tire can be viewed
in the DIC. The tire pressure will be
shown in either kilopascals (kPa) or
pounds per square inch (psi). Press the vehicle information button until
the DIC displays FRONT
TIRES kPa (PSI) LEFT ##
RIGHT ##. Press the vehicle
information button again until the
DIC displays REAR TIRES kPa
(PSI) LEFT ## RIGHT ##.
If a low tire pressure condition is
detected by the system while
driving, a message advising you to
add pressure in a specific tire will
appear in the display. See
Tire
Pressure on page 10‑56 andTire
Messages on page 5‑44 for more
information.
If the tire pressure display shows
dashes instead of a value, there
may be a problem with your vehicle.
If this consistently occurs, see your
dealer for service.
Trailer Gain and Output
On vehicles with the Integrated
Trailer Brake Control (ITBC) system,
the trailer brake display appears in
the DIC. Press the vehicle
information button until TRAILER
GAIN and OUTPUT display.

Black plate (37,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-37
Oil Life
To access this display, the vehicle
must be in P (Park). Press the trip
odometer reset stem until OIL LIFE
REMAINING displays. This display
shows an estimate of the oil's
remaining useful life. If you see
99% OIL LIFE REMAINING on the
display, that means 99% of the
current oil life remains. The engine
oil life system will alert you to
change the oil on a schedule
consistent with your driving
conditions.
When the remaining oil life is low,
the CHANGE ENGINE OIL SOON
message will appear on the display.
See“CHANGE ENGINE OIL SOON”
under Engine Oil Messages on
page 5‑40. You should change the
oil as soon as you can. See Engine
Oil on page 10‑8. In addition to the
engine oil life system monitoring the
oil life, additional maintenance is
recommended in the Maintenance
Schedule in this manual. See
Maintenance Schedule on
page 11‑3 for more information. Remember, you must reset the OIL
LIFE display yourself after each oil
change. It will not reset itself. Also,
be careful not to reset the OIL LIFE
display accidentally at any time
other than when the oil has just
been changed. It cannot be reset
accurately until the next oil change.
To reset the engine oil life system,
see
Engine Oil Life System on
page 10‑10.
Relearn Tire Positions
Your vehicle may have this display.
To access this display, the vehicle
must be in P (Park). If your vehicle
has the Tire Pressure Monitor
System (TPMS), after rotating the
tires or after replacing a tire or
sensor, the system must re-learn the
tire positions. To re-learn the tire
positions, see Tire Pressure Monitor
System on page 10‑58. See Tire
Inspection on page 10‑62, Tire
Rotation on page 10‑62 andTire
Messages on page 5‑44 for more
information.Vehicle Messages
Messages displayed on the DIC
indicate the status of the vehicle or
some action may be needed to
correct a condition. Multiple
messages may appear one after
another.
The messages that do not require
immediate action can be
acknowledged and cleared by
pressing
V(Set/Reset) or the trip
odometer reset stem.
The messages that require
immediate action cannot be cleared
until that action is performed.
All messages should be taken
seriously and clearing the message
does not correct the problem.
The following are the possible
messages and some information
about them.

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 (4,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-4 Driving and Operating
Braking
Braking action involves perception
time and reaction time. Deciding to
push the brake pedal is perception
time. Actually doing it is
reaction time.
Average driver reaction time is
about three‐fourths of a second. In
that time, a vehicle moving at
100 km/h (60 mph) travels 20 m
(66 ft), which could be a lot of
distance in an emergency.
Helpful braking tips to keep in mind
include:
.Keep enough distance between
you and the vehicle in front
of you.
.Avoid needless heavy braking.
.Keep pace with traffic.
If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the
brakes. Doing so could make the
pedal harder to push down. If the
engine stops, there will be some power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop and the
brake pedal will be harder to push.
Steering
Hydraulic Power Steering
Your vehicle has hydraulic power
steering. It may require
maintenance. See Power Steering
Fluid
Power Steering Fluid on
page 10‑24.
If power steering assist is lost
because the engine stops or the
power steering system is not
functioning, the vehicle can be
steered but may required increased
effort. See your dealer if there is a
problem.
If the vehicle is a hybrid, see the
hybrid supplement for more
information.
Curve Tips
.Take curves at a reasonable
speed.
.Reduce speed before entering a
curve.
.Maintain a reasonable steady
speed through the curve
.Wait until the vehicle is out of
the curve before accelerating
gently into the straightaway.
Steering in Emergencies
.There are some situations when
steering around a problem may
be more effective than braking.
.Holding both sides of the
steering wheel allows you to turn
180 degrees without removing
a hand.
.Antilock Brake System (ABS)
allows steering while braking.

Black plate (6,1)GMC Yukon/Yukon XL Owner Manual - 2012
9-6 Driving and Operating
.Try to avoid sudden steering,
acceleration, or braking,
including reducing vehicle speed
by shifting to a lower gear. Any
sudden changes could cause
the tires to slide.
Remember: Antilock brakes help
avoid only the braking skid.
Off-Road Driving
Four-wheel-drive vehicles can be
used for off-road driving. Vehicles
without four-wheel drive and
vehicles not equipped with All
Terrain (AT) or On-Off Road (OOR)
tires must not be driven off-road
except on a level, solid surface. To
contact the tire manufacturer for
more information about the original
equipment tires, see the Limited
Warranty and Owner Assistance
Information manual. Controlling the vehicle is the key to
successful off-road driving. One of
the best ways to control the vehicle
is to control the speed.
{WARNING
When driving off-road, bouncing
and quick changes in direction
can easily throw you out of
position. This could cause you to
lose control and crash. You and
your passengers should always
wear safety belts.
Before Driving Off-Road
.Have all necessary maintenance
and service work completed.
.Fuel the vehicle, fill fluid levels,
and check inflation pressure in
all tires, including the spare,
if equipped.
.Read all the information about
four-wheel-drive vehicles in this
manual.
.Make sure all underbody
shields, if equipped, are properly
attached.
.Know the local laws that apply to
off-road driving.
To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower
air dam.
Notice: Operating the vehicle for
extended periods without the
front fascia lower air dam
installed can cause improper air
flow to the engine. Re‐attach the
front fascia air dam after off-road
driving.