check engine GMC SIERRA 2015 User Guide

Black plate (20,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-20 Instruments and Controls
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 may require at least one full tank
of the proper fuel to turn the light off.
See Fuel on page 9-63.
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.
Emissions Inspection and
Maintenance Programs
Depending on where you live, your
vehicle may be required to
participate in an emission control
system inspection and maintenance
program. For the inspection, the
emission system test equipment will
likely connect 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/RUN
while 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.

Black plate (24,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-24 Instruments and Controls
Traction Control System
(TCS)/StabiliTrak®Light
This light comes on briefly when the
engine is started.
If the light does not come on, have
the vehicle serviced by your dealer.
If the system is working normally,
the indicator light turns off.
If the light is on and not flashing, the
TCS and potentially the StabiliTrak
system have been disabled. A DIC
message may display. Check the
DIC messages to determine which
feature(s) is no longer functioning
and whether the vehicle requires
service.If the indicator/warning light is on
and flashing, the TCS and/or the
StabiliTrak system is actively
working.
See
Traction Control/Electronic
Stability Control on page 9-49.
Engine Coolant
Temperature Warning
Light
This light comes on briefly while
starting the vehicle.
If it does not, have the vehicle
serviced by the dealer. If the system
is working normally the indicator
light goes off.
{Caution
The engine coolant temperature
warning light indicates that the
vehicle has overheated. Driving
with this light on can damage the
engine and it may not be covered
by the vehicle warranty. See
Engine Overheating on
page 10-21.
The engine coolant temperature
warning light comes on when the
engine has overheated.
If this happens, pull over and turn
off the engine as soon as possible.
See Engine Overheating on
page 10-21.

Black plate (25,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-25
Tire Pressure Light
For vehicles with the Tire Pressure
Monitor System (TPMS), this light
comes on briefly when the engine is
started. It provides information
about tire pressures and the TPMS.
When the Light Is On Steady
This indicates that one or more of
the tires are significantly
underinflated.
A Driver Information Center (DIC)
tire pressure message may also
display. SeeTire Messages on
page 5-38. Stop as soon as
possible, and inflate the tires to the
pressure value shown on the Tire
and Loading Information label. See
Tire Pressure on page 10-59. When the Light Flashes First and
Then Is On Steady
If the light flashes for about a minute
and then stays on, there may be a
problem with the TPMS. If the
problem is not corrected, the light
will come on at every ignition cycle.
See
Tire Pressure Monitor
Operation on page 10-62.
Engine Oil Pressure Light
{Caution
Lack of proper engine oil
maintenance can damage the
engine. Driving with the engine
oil low can also damage the
engine. The repairs would not be
covered by the vehicle warranty.
Check the oil level as soon as
possible. Add oil if required, but if
the oil level is within the operating
range and the oil pressure is still
low, have the vehicle serviced.
Always follow the maintenance
schedule for changing engine oil.
This light should come on briefly as
the engine is started. If it does not
come on, have the vehicle serviced
by your dealer.
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 might have
some other system problem. See
your dealer.
Low Fuel Warning Light

Black plate (26,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-26 Instruments and Controls
This light is near the fuel gauge and
comes on briefly when the ignition is
turned on as a check to show it is
working.
It also comes on when the fuel tank
is low on fuel. The light turns off
when fuel is added. If it does not,
have the vehicle serviced.
Security Light
The security light should come on
briefly as the engine is started. If it
does not come on, have the vehicle
serviced by your dealer. If the
system is working normally, the
indicator light turns off.If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent
system. See
Immobilizer Operation
on page 2-13.
High-Beam On Light
This light comes on when the
high-beam headlamps are in use.
See Headlamp High/Low-Beam
Changer on page 6-2.
Front Fog Lamp Light
For vehicles with fog lamps, this
light comes on when the fog lamps
are on.
The light goes out when the fog
lamps are turned off. See Fog
Lamps on page 6-5 for more
information.
Lamps On Reminder
This light comes on when the
exterior lamps are in use. See
Exterior Lamp Controls on page 6-1.

Black plate (33,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-33
Door Ajar Messages
DOOR OPEN
This message displays and a chime
may sound if a door is not fully
closed. 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
may sound 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.
Engine Cooling System
Messages
A/C OFF DUE TO HIGH
ENGINE TEMP
This message displays when the
engine coolant becomes hotter than
the normal operating temperature.
SeeEngine Coolant Temperature
Gauge on page 5-13. 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.
If this message continues to appear,
have the system repaired by your
dealer as soon as possible to avoid
damage to the engine.
ENGINE OVERHEATING IDLE
ENGINE
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 5-13.
When towing, use Tow/Haul mode
to prevent damage to the engine or
transmission. See Tow/Haul Mode
on page 9-39.
ENGINE OVERHEATED STOP
ENGINE
This message displays and a chime
may sound 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.

Black plate (34,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
5-34 Instruments and Controls
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. SeeEngine
Oil Life System on page 10-11 for
information on how to reset the
message. See Engine Oil on
page 10-8 andMaintenance
Schedule on page 11-3.
ENGINE OIL LOW ADD OIL
On some vehicles, this message
displays when the engine oil level
may be too low. Check the oil level
before filling to the recommended
level. If the oil is not low and this
message remains on, take the
vehicle to your dealer for service.
See Engine Oil on page 10-8.
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 5-13.
OIL PRESSURE LOW STOP
ENGINE
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
may sound 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 more information.
This message also displays when
the vehicle's 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.

Black plate (37,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-37
TRACTION CONTROL OFF
This message displays when the
traction control has been turned off.
SeeTraction Control/Electronic
Stability Control on page 9-49.
TRACTION CONTROL ON
This message displays when the
traction control is active. See
Traction Control/Electronic Stability
Control on page 9-49.
STABILITRAK OFF
This message displays when the
StabiliTrak system has been turned
off. Adjust your driving accordingly.
To limit wheel spin and realize the
full benefits of the stability
enhancement system, you should
normally leave StabiliTrak on. See
Traction Control/Electronic Stability
Control on page 9-49. STABILITRAK OFF may also
display when the stability control
has been automatically disabled.
The following conditions can cause
this message to appear:
.The system is overheating,
which could occur if StabiliTrak
activates continuously for an
extended period of time.
.The brake system warning light
is on. See
Brake System
Warning Light on page 5-21.
.The stability system takes longer
than usual to complete its
diagnostic checks due to driving
conditions.
.An engine or vehicle-related
problem has been detected and
the vehicle needs service. See
your dealer.
.The transfer case is in
Four-Wheel Drive Low.
The message turns off as soon as
the conditions that caused the
message to be displayed are no
longer present.
Airbag System Messages
SERVICE AIRBAG
This message displays if there is a
problem with the airbag system.
Take the vehicle to your dealer for
service.
Safety Belt Messages
SHIFTER LOCKED. BUCKLE
SEATBELT
This message displays if the vehicle
is equipped with the Safety Belt
Assurance System and the driver
and front outboard passenger,
if present, safety belts are not
buckled. The vehicle will not shift
out of P (Park). Buckle the safety
belt(s) to unlock the shift lever.
This system may not allow the
vehicle to shift out of P (Park) if an
object - such as a briefcase,
handbag, grocery bag, laptop,
or other electronic device - is on the
front outboard passenger seat.

Black plate (41,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-41
TRANSMISSION HOT IDLE
ENGINE
This message displays and a chime
may 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. This message clears and the
chime stops when the fluid
temperature reaches a safe level.
When towing, use Tow/Haul Mode
to prevent damage to the engine or
transmission. SeeTow/Haul Mode
on page 9-39.
VEHICLE IN 4WD LOW
This message will display if the
vehicle is driven in 4
nfor about
10 minutes above 72 km/h (45 mph).
Vehicle Reminder
Messages
CHECK TRAILER WIRING
On vehicles with the Integrated
Trailer Brake Control (ITBC) system,
this message may display and a
chime may sound when one of the
following conditions exists:
.A trailer with electric brakes
becomes disconnected from the
vehicle.
‐ If the disconnect occurs while
the vehicle is stopped, this
message clears itself after a
short time.
‐ If the disconnect occurs while
the vehicle is moving, this
message stays on until the
ignition is turned off.
.There is a short in the wiring to
the electric trailer brakes.
When this message displays, power
is no longer available to the trailer
brakes. As soon as it is safe to do so,
carefully pull the vehicle over to the
side of the road and turn the ignition
off. Check the wiring connection to
the trailer and turn the ignition back
on. This message clears if the trailer
is reconnected. This message also
clears if you acknowledge it. If this
message still displays, either the
vehicle or the trailer needs service.
See your dealer.
See
“Integrated Trailer Brake
Control System” underTowing
Equipment on page 9-78.
ICE POSSIBLE DRIVE
WITH CARE
This message displays when ice
conditions are possible.
TRAILER CONNECTED
On vehicles with the Integrated
Trailer Brake Control (ITBC) system,
this message displays briefly when
a trailer with electric or electric over
hydraulic brakes is first connected
to the vehicle.

Black plate (12,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-12 Driving and Operating
.Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.Shift to a lower gear when going
down steep or long hills.
{Warning
Using the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.
{Warning
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. This can cause
overheating of the brakes and(Continued)
Warning (Continued)
loss of steering. Always have the
engine running and the vehicle
in gear.
.Stay in your own lane. Do not
swing wide or cut across the
center of the road. Drive at
speeds that let you stay in your
own lane.
.Be alert on top of hills;
something could be in your lane
(stalled car, accident).
.Pay attention to special road
signs (falling rocks area, winding
roads, long grades, passing or
no-passing zones) and take
appropriate action.
Winter Driving
Driving on Snow or Ice
Drive carefully when there is snow
or ice between the tires and the
road, creating less traction or grip. Wet ice can occur at about 0°C
(32°F) when freezing rain begins to
fall, resulting in even less traction.
Avoid driving on wet ice or in
freezing rain until roads can be
treated with salt or sand.
Drive with caution, whatever the
condition. Accelerate gently so
traction is not lost. Accelerating too
quickly causes the wheels to spin
and makes the surface under the
tires slick, so there is even less
traction.
Traction Control should be turned
on. See
Traction Control/Electronic
Stability Control on page 9-49.
The Antilock Brake System (ABS)
improves vehicle stability during
hard stops on slippery roads, but
apply the brakes sooner than when
on dry pavement. See Antilock
Brake System (ABS) on page 9-46.
Allow greater following distance on
any slippery road and watch for
slippery spots. Icy patches can
occur on otherwise clear roads in
shaded areas. The surface of a

Black plate (13,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-13
curve or an overpass can remain icy
when the surrounding roads are
clear. Avoid sudden steering
maneuvers and braking while
on ice.
Turn off cruise control on slippery
surfaces.
Blizzard Conditions
Being stuck in snow can be a
serious situation. Stay with the
vehicle unless there is help nearby.
If possible, use Roadside
Assistance. SeeRoadside
Assistance Program on page 13-5.
To get help and keep everyone in
the vehicle safe:
.Turn on the hazard warning
flashers.
.Tie a red cloth to an outside
mirror.
{Warning
Snow can trap engine exhaust
under the vehicle. This may
cause exhaust gases to get
inside. Engine exhaust contains
carbon monoxide (CO) which
cannot be seen or smelled. It can
cause unconsciousness and even
death.
If the vehicle is stuck in the snow:
.Clear away snow from around
the base of your vehicle,
especially any that is blocking
the exhaust pipe.
.Check again from time to
time to be sure snow does
not collect there.
.Open a window about 5 cm
(2 in) on the side of the
vehicle that is away from the
wind to bring in fresh air.
(Continued)
Warning (Continued)
.Fully open the air outlets on
or under the instrument
panel.
.Adjust the climate control
system to a setting that
circulates the air inside the
vehicle and set the fan speed
to the highest setting. See
“Climate Control Systems”.
For more information about
carbon monoxide, see Engine
Exhaust on page 9-32.
To save fuel, run the engine for only
short periods as needed to warm
the vehicle and then shut the engine
off and close the window most of
the way to save heat. Repeat this
until help arrives but only when you
feel really uncomfortable from the
cold. Moving about to keep warm
also helps.