2012 GMC YUKON check engine

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 (22,1)GMC Yukon/Yukon XL Owner Manual - 2012
5-22 Instruments and Controls
To prevent more serious damage to
the vehicle:
.Reduce vehicle speed.
.Avoid hard accelerations.
.Avoid steep uphill grades.
.If towing a trailer, reduce the
amount of cargo being hauled as
soon as it is possible.
If the light continues to flash, stop
and park the vehicle. Turn the
vehicle off, wait at least 10 seconds,
and restart the engine. If the light is
still flashing, follow the previous
steps and see your dealer for
service as soon as possible.
Light On Steady: An emission
control system malfunction has
been detected on the vehicle.
Diagnosis and service might be
required. The following may correct an
emission system malfunction:
.Check that the fuel cap is fully
installed. 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 the
light off.
.Check that good quality fuel is
used. Poor fuel quality causes
the engine not to run as
efficiently as designed and may
cause stalling after start-up,
stalling when the vehicle is
changed into gear, misfiring,
hesitation on acceleration,
or stumbling on acceleration.
These conditions might go away
once the engine is warmed up. If one or more of these conditions
occurs, change the fuel brand used.
It will require at least one full tank of
the proper fuel to turn the light off.
See
Recommended Fuel on
page 9‑62.
If none of the above have made the
light turn off, your dealer can check
the vehicle. The dealer has the
proper test equipment and
diagnostic tools to fix any
mechanical or electrical problems
that might have developed.

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 (39,1)GMC Yukon/Yukon XL Owner Manual - 2012
Instruments and Controls 5-39
See“Integrated Trailer Brake
Control System” underTowing
Equipment on page 9‑76 for more
information.
Door Ajar Messages
DRIVER DOOR OPEN
This message displays and a chime
sounds if the driver door is not fully
closed and the vehicle is shifted out
of P (Park). Stop and turn off the
vehicle, check the door for
obstructions, and close the door
again. Check to see if the message
still appears on the DIC.
HOOD OPEN
This message displays and a chime
sounds if the hood is not fully
closed. Stop and turn off the
vehicle, check the hood for
obstructions, and close the hood
again. Check to see if the message
still appears on the DIC.
LEFT REAR DOOR OPEN
This message displays and a chime
sounds if the driver side rear door is
not fully closed and the vehicle is
shifted out of P (Park). Stop and turn
off the vehicle, check the door for
obstructions, and close the door
again. Check to see if the message
still appears on the DIC.
PASSENGER DOOR OPEN
This message displays and a chime
sounds if the front passenger door
is not fully closed and the vehicle is
shifted out of P (Park). Stop and turn
off the vehicle, check the door for
obstructions, and close the door
again. Check to see if the message
still appears on the DIC.
REAR ACCESS OPEN
This message displays and a chime
sounds if the liftgate or liftglass is
open while the ignition is in ON/
RUN. Turn off the vehicle and check
the liftgate and liftglass. Restart the
vehicle and check for the message
on the DIC display.
RIGHT REAR DOOR OPEN
This message displays and a chime
sounds if the passenger side rear
door is not fully closed and the
vehicle is shifted out of P (Park).
Stop and turn off the vehicle, check
the door for obstructions, and close
the door again. Check to see if the
message still appears on the DIC.
Engine Cooling System
Messages
ENGINE HOT A/C (Air
Conditioning) TURNED OFF
This message displays when the
engine coolant becomes hotter than
the normal operating temperature.
See Engine Coolant Temperature
Gauge on page 5‑16. To avoid
added strain on a hot engine, the air
conditioning compressor
automatically turns off. When the
coolant temperature returns to
normal, the air conditioning
compressor turns back on. You can
continue to drive your vehicle.

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 (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.