2015 GMC SIERRA DENALI check engine light

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. See Tire 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
{ CautionLack 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 (37,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-37TRACTION CONTROL OFF This message displays when the
traction control has been turned off.
See Traction 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 (46,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
9-46 Driving and Operating This will take at least
10 seconds. Then slowly release
the dial to the 4
n position. The
N (Neutral) light will come on
when the transfer case shift to
N (Neutral) is complete.
7. With the engine running, verify
that the transfer case is in
N (Neutral) by shifting the
transmission to R (Reverse),
then shift the transmission to
D (Drive). There should be no
movement of the vehicle while
shifting the transmission.
8. Turn the engine off, and the
ignition to ACC/ACCESSORY.
9. Place the transmission shift
lever in P (Park).
10. See Recreational Vehicle
Towing on page 10-91 .
11. Turn the ignition to LOCK/OFF. Shifting Out of N (Neutral)
To shift:
1. Set the parking brake and apply
the brake pedal.
2. Turn the ignition to ON/RUN with
the engine off.
3. Shift the transmission to
N (Neutral).
4. Turn the transfer case knob to
the desired setting.
After the transfer case has
shifted out of N (Neutral), the
N (Neutral) light will go out.
5. Release the parking brake.
6. Start the engine and shift the
transmission to the desired gear. Brakes Antilock Brake
System (ABS) This vehicle has ABS, an advanced
electronic braking system that helps
prevent a braking skid.
When the vehicle begins to drive
away, ABS checks itself.
A momentary motor or clicking noise
might be heard while this test is
going on, and it might even be
noticed that the brake pedal moves
a little. This is normal.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
on page 5-21 .

Black plate (87,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-87continues over multiple ignition
cycles, there is a problem with the
ITBC system. Have the vehicle
serviced.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message displays
while driving, the ITBC system may
not be fully functional or may not
function at all. When traffic
conditions allow, 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. If either of
these messages continues, either
the vehicle or trailer needs service.
A GM dealer may be able to
diagnose and repair problems with
the trailer. However, any diagnosis
and repair of the trailer is not
covered under the vehicle warranty.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information. Trailer Sway
Control (TSC) Vehicles with StabiliTrak have a
TSC feature. Trailer sway is
unintended side-to-side motion of a
trailer while being towed. If the
vehicle is towing a trailer and the
TSC detects that sway is increasing,
the vehicle brakes are selectively
applied at each wheel, to help
reduce excessive trailer sway. If the
vehicle is equipped with the
Integrated Trailer Brake Control
(ITBC) system, and the trailer has
the electric actuated brake system,
StabiliTrak may also apply the trailer
brakes.
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on the
instrument cluster. Vehicle speed
must be reduced. If trailer sway
continues, StabiliTrak can reduce
engine torque to help slow the
vehicle. See Traction Control/
Electronic Stability Control on
page 9-49 .{ WarningEven if the vehicle is equipped
with TSC, trailer sway could result
in loss of control and the vehicle
could crash. If excessive trailer
sway is detected, slow down to a
safe speed. Check the trailer and
vehicle to help correct possible
causes. These could include an
improperly or overloaded trailer,
unrestrained cargo, improper
trailer hitch configuration,
excessive vehicle-trailer speed,
or improperly inflated or incorrect
vehicle or trailer tires. See Towing
Equipment on page 9-78 for
trailer ratings and hitch setup
recommendations.
Adding non-dealer accessories can
affect the vehicle performance. See
Accessories and Modifications on
page 10-3 .

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-1
Vehicle Care General Information General Information . . . . . . . . . . 10-2
California Proposition
65 Warning . . . . . . . . . . . . . . . . . 10-2
California Perchlorate
Materials Requirements . . . . 10-3
Accessories and
Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks Doing Your Own
Service Work . . . . . . . . . . . . . . . 10-3
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Engine Compartment
Overview . . . . . . . . . . . . . . . . . . . 10-5
Engine Oil . . . . . . . . . . . . . . . . . . . 10-8
Engine Oil Life System . . . . . 10-11
Automatic Transmission
Fluid (6 Speed
Transmission) . . . . . . . . . . . . . 10-12
Automatic Transmission
Fluid (8 Speed
Transmission) . . . . . . . . . . . . . 10-15
Engine Air Cleaner/Filter . . . . 10-15
Cooling System . . . . . . . . . . . . 10-17
Engine Coolant . . . . . . . . . . . . . 10-18 Engine Overheating . . . . . . . . 10-21
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-23
Engine Fan . . . . . . . . . . . . . . . . . 10-24
Power Steering Fluid (1500
Series) . . . . . . . . . . . . . . . . . . . . 10-24
Power Steering Fluid (2500/
3500 Series) . . . . . . . . . . . . . . 10-24
Washer Fluid . . . . . . . . . . . . . . . 10-25
Brakes . . . . . . . . . . . . . . . . . . . . . 10-26
Brake Fluid . . . . . . . . . . . . . . . . . 10-27
Battery . . . . . . . . . . . . . . . . . . . . . 10-29
Four-Wheel Drive . . . . . . . . . . . 10-29
Front Axle . . . . . . . . . . . . . . . . . . 10-30
Rear Axle . . . . . . . . . . . . . . . . . . 10-31
Noise Control System . . . . . . 10-32
Starter Switch Check . . . . . . . 10-33
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-34
Ignition Transmission Lock
Check . . . . . . . . . . . . . . . . . . . . . 10-34
Park Brake and P (Park)
Mechanism Check . . . . . . . . 10-34
Wiper Blade
Replacement . . . . . . . . . . . . . . 10-35
Glass Replacement . . . . . . . . 10-35 Headlamp Aiming Headlamp Aiming . . . . . . . . . . 10-36
Bulb Replacement Bulb Replacement . . . . . . . . . . 10-36
Halogen Bulbs . . . . . . . . . . . . . . 10-36
LED Lighting . . . . . . . . . . . . . . . 10-36
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-36
Fog Lamps . . . . . . . . . . . . . . . . . 10-37
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-37
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . 10-39
Replacement Bulbs . . . . . . . . . 10-40
Electrical System Electrical System
Overload . . . . . . . . . . . . . . . . . . 10-40
Fuses . . . . . . . . . . . . . . . . . . . . . . 10-41
Engine Compartment Fuse
Block . . . . . . . . . . . . . . . . . . . . . 10-41
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . 10-45
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . 10-48

Black plate (28,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-28 Vehicle Care
{ WarningIf 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 on page 5-21 .
Refer to the Maintenance Schedule
to determine when to check the
brake fluid. See Maintenance
Schedule on page 11-3 .
Checking Brake Fluid
Check brake fluid by looking at the
brake fluid reservoir. See Engine
Compartment Overview on
page 10-5 . The fluid level should be above
MIN. 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 is above MIN but not over the
MAX mark.
What to Add
Use only new DOT 3 brake fluid
from a sealed container. See
Recommended Fluids and
Lubricants on page 11-12 . Always clean the brake fluid
reservoir cap and the area around
the cap before removing it. This
helps keep dirt from entering the
reservoir.
{ WarningWith 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.
{ Caution .
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
(Continued)

Black plate (89,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-89
{ WarningUsing 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.
Battery fluid contains acid that
can burn you. Do not get it on
you. If you accidentally get it in
your eyes or on your skin, flush
the place with water and get
medical help immediately. { WarningFans or other moving engine
parts can injure you badly. Keep
your hands away from moving
parts once the engine is running.
6. Check that the jumper cables do
not have loose or missing
insulation. If they do, you could
get a shock. The vehicles could
be damaged too.
Before you connect the cables,
here are some basic things you
should know. Positive (+) will go
to positive (+) or to a remote
positive (+) terminal if the
vehicle has one. Negative ( − )
will go to a heavy, unpainted
metal engine part or to a remote
negative ( − ) terminal if the
vehicle has one.
Do not connect positive (+) to
negative ( − ) or you will get a
short that would damage the
battery and maybe other parts too. And do not connect the
negative ( − ) cable to the
negative ( − ) terminal on the
dead battery because this can
cause sparks.
5.3L Shown, 6.0L, 6.2L, and 6.6L
Similar
7. Connect the red positive (+)
cable to the positive (+) terminal
of the vehicle with the dead
battery.
8. Do not let the other end touch
metal. Connect it to the
positive (+) terminal of the good