cooling GMC SIERRA 2015 Owner's Manual

Black plate (14,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
1-14 In Brief
OFF:Turns the windshield
wipers off.
8: For a single wipe, turn to8,
then release. For several wipes,
hold the band on
8longer.
L m:Push the paddle at the top of
the lever to spray washer fluid on
the windshield.
See Windshield Wiper/Washer on
page 5-3.
Climate Controls
The heating, cooling, and ventilation in the vehicle can be controlled with
this system.
1. Driver Temperature Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger Temperature Control
7. AUTO (Automatic Operation)
8. Air Recirculation 9. Power Button
10. Rear Window Defogger
11. SYNC (Synchronized
Temperature)
See Dual Automatic Climate Control
System on page 8-1.

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Instruments and Controls 5-1
Instruments and
Controls
Controls
Steering Wheel Adjustment . . . 5-2
Steering Wheel Controls . . . . . . 5-2
Heated Steering Wheel . . . . . . . 5-3
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3
Windshield Wiper/Washer . . . . . 5-3
Compass . . . . . . . . . . . . . . . . . . . . . 5-4
Clock . . . . . . . . . . . . . . . . . . . . . . . . . 5-4
Power Outlets . . . . . . . . . . . . . . . . . 5-5
Warning Lights, Gauges, and
Indicators
Warning Lights, Gauges, andIndicators . . . . . . . . . . . . . . . . . . . . 5-8
Instrument Cluster . . . . . . . . . . . . 5-9
Speedometer . . . . . . . . . . . . . . . . 5-11
Odometer . . . . . . . . . . . . . . . . . . . . 5-11
Trip Odometer . . . . . . . . . . . . . . . 5-11
Tachometer . . . . . . . . . . . . . . . . . . 5-11
Fuel Gauge . . . . . . . . . . . . . . . . . . 5-12
Engine Oil Pressure Gauge . . . . . . . . . . . . . . . . . . . . . . 5-12
Engine Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . 5-13 Transmission Temperature
Gauge . . . . . . . . . . . . . . . . . . . . . . 5-14
Voltmeter Gauge . . . . . . . . . . . . . 5-15
Safety Belt Reminders . . . . . . . 5-15
Airbag Readiness Light . . . . . . 5-16
Passenger Airbag Status Indicator . . . . . . . . . . . . . . . . . . . . 5-17
Charging System Light . . . . . . 5-18
Malfunction Indicator Lamp . . . . . . . . . . . . . 5-18
Brake System Warning Light . . . . . . . . . . . . . . . . . . . . . . . 5-21
Antilock Brake System (ABS) Warning Light . . . . . . . . . . . . . . 5-21
Four-Wheel-Drive Light . . . . . . 5-22
Tow/Haul Mode Light . . . . . . . . 5-22
Hill Descent Control Light . . . . 5-22
Lane Departure Warning (LDW) Light . . . . . . . . . . . . . . . . 5-22
Vehicle Ahead Indicator . . . . . . 5-23
Traction Off Light . . . . . . . . . . . . 5-23
StabiliTrak
®OFF Light . . . . . . . 5-23
Traction Control System (TCS)/StabiliTrak
®Light . . . . 5-24
Engine Coolant Temperature Warning Light . . . . . . . . . . . . . . 5-24
Tire Pressure Light . . . . . . . . . . 5-25
Engine Oil Pressure Light . . . . 5-25
Low Fuel Warning Light . . . . . . 5-25 Security Light . . . . . . . . . . . . . . . . 5-26
High-Beam On Light . . . . . . . . . 5-26
Front Fog Lamp Light . . . . . . . . 5-26
Lamps On Reminder . . . . . . . . . 5-26
Cruise Control Light . . . . . . . . . 5-27
Door Ajar Light . . . . . . . . . . . . . . 5-27
Information Displays
Driver Information
Center (DIC) . . . . . . . . . . . . . . . 5-27
Vehicle Messages
Vehicle Messages . . . . . . . . . . . 5-31
Battery Voltage and ChargingMessages . . . . . . . . . . . . . . . . . . 5-31
Brake System Messages . . . . 5-32
Compass Messages . . . . . . . . . 5-32
Door Ajar Messages . . . . . . . . . 5-33
Engine Cooling System Messages . . . . . . . . . . . . . . . . . . 5-33
Engine Oil Messages . . . . . . . . 5-34
Engine Power Messages . . . . 5-34
Fuel System Messages . . . . . . 5-35
Key and Lock Messages . . . . . 5-35
Lamp Messages . . . . . . . . . . . . . 5-35
Object Detection System Messages . . . . . . . . . . . . . . . . . . 5-35
Ride Control System Messages . . . . . . . . . . . . . . . . . . 5-36

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 (8,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
6-8 Lighting
Lighting Features
Entry Lighting
The vehicle has an illuminated entry
feature.
When a door is opened, the dome
lamps and puddle lamps come on if
the dome lamp control is in the
DOOR position. If the dome lamp
control is in the OFF position, the
lamps do not come on.
The headlamps, parking lamps,
taillamps, and back-up lamps turn
on briefly at night, or in areas with
limited lighting, when
Kis pressed
on the Remote Keyless Entry (RKE)
transmitter. After about 30 seconds
the exterior lamps turn off. Entry
lighting can be disabled manually by
changing the ignition out of the OFF
position, or by pressing the RKE
transmitter
Qbutton.
This feature can be changed. See
“Vehicle Locator Lights” under
Vehicle Personalization on
page 5-42.
Exit Lighting
The interior lamps, headlamps,
parking lamps, back-up lamps, and
license plate lamps come on when
the key is removed from the ignition.
The interior lamps turn off
automatically in 20 seconds. The
interior lamps do not come on if the
dome lamp control is in the OFF
position.
The exterior lamps turn off
immediately by turning the exterior
lamps control off.
This feature can be changed. See
Vehicle Personalization on
page 5-42.
Battery Load
Management
The vehicle has Electric Power
Management (EPM), which
estimates the battery's temperature
and state of charge. It then adjusts
the voltage for best performance
and extended life of the battery. When the battery's state of charge
is low, the voltage is raised slightly
to quickly bring the charge back up.
When the state of charge is high,
the voltage is lowered slightly to
prevent overcharging. The voltmeter
gauge or the voltage display on the
Driver Information Center (DIC),
if equipped, may show the voltage
moving up or down. This is normal.
If there is a problem, an alert will be
displayed.
The battery can be discharged at
idle if the electrical loads are very
high. This is true for all vehicles.
This is because the generator
(alternator) may not be spinning fast
enough at idle to produce all the
power that is needed for very high
electrical loads.
A high electrical load occurs when
several of the following are on, such
as: headlamps, high beams, fog
lamps, rear window defogger,
climate control fan at high speed,
heated seats, engine cooling fans,
trailer loads, and loads plugged into
accessory power outlets.

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Climate Controls 8-1
Climate Controls
Climate Control Systems
Dual Automatic Climate ControlSystem . . . . . . . . . . . . . . . . . . . . . . 8-1
Air Vents
Air Vents . . . . . . . . . . . . . . . . . . . . . . 8-4
Maintenance
Passenger Compartment AirFilter . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Service . . . . . . . . . . . . . . . . . . . . . . . 8-6
Climate Control Systems
Dual Automatic Climate Control System
With this system the heating, cooling, and ventilation in the vehicle can be
controlled.
1. Driver Temperature Control
2. A/C (Air Conditioning)
3. Air Delivery Mode Controls
4. Fan Control
5. Defrost
6. Passenger Temperature Control 7. AUTO (Automatic Operation)
8. Air Recirculation
9. Power Button
10. Rear Window Defogger
11. SYNC (Synchronized
Temperature)

Black plate (11,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-11
suspension, wheels, tires, and
exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance service
is required. See theMaintenance
Schedule on page 11-3.
Driving on Wet Roads
Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep‐standing or flowing water.
{Warning
Wet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
(Continued)
Warning (Continued)
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is
wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road. There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips
Besides slowing down, other wet
weather driving tips include:
.Allow extra following distance.
.Pass with caution.
.Keep windshield wiping
equipment in good shape.
.Keep the windshield washer fluid
reservoir filled.
.Have good tires with proper
tread depth. See
Tires on
page 10-50.
.Turn off cruise control.
Hill and Mountain Roads
Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips for
driving in these conditions include:
.Keep the vehicle serviced and in
good shape.

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 (39,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-39
Low Traction Mode
If equipped, Low Traction Mode
assists in vehicle acceleration when
road conditions are slippery, such
as with ice or snow. While the
vehicle is at a stop, select M2 using
Range Selection Mode. This will
limit torque to the wheels and help
to prevent the tires from spinning.
Tow/Haul Mode
The vehicle has a Tow/Haul Mode.
The Tow/Haul Mode adjusts the
transmission shift pattern to reduceshift cycling, providing increased
performance, vehicle control, and
enhanced transmission and engine
cooling when driving down steep
hills or mountain grades, towing,
or hauling heavy loads.
The selector button is on the end of
the shift lever. Turn the Tow/Haul
Mode on and off by pressing the
button. When the Tow/Haul Mode is
enabled, a light on the instrument
cluster will come on.
See
Tow/Haul Mode Light on
page 5-22 andHill and Mountain
Roads on page 9-11.
Also see “Tow/Haul Mode” under
Towing Equipment on page 9-78.
Tow/Haul Mode Grade Braking
Tow/Haul Mode Grade Braking is
only enabled while the Tow/Haul
Mode is selected and the vehicle is
not in the Range Selection Mode.
See “Tow/Haul Mode” listed
previously and Manual Mode on
page 9-36. Tow/Haul Mode Grade
Braking assists in maintaining desired vehicle speeds when driving
on downhill grades by using the
engine and transmission to slow the
vehicle.
On vehicles with a gasoline engine,
to disable or enable Tow/Haul
Grade Braking within the current
ignition key cycle, press and hold
the Tow/Haul button for
five seconds. When the button is
released, the requested mode
change is made. A DIC message is
displayed. See
Transmission
Messages on page 5-39.
On vehicles with a diesel engine,
Tow/Haul Mode Grade Braking can
be enabled or disabled by pressing
the Tow/Haul Mode button. Use the
exhaust brake and Tow/Haul Mode
for maximum grade braking.
See Towing Equipment on
page 9-78.
For other forms of grade braking,
see Automatic Transmission on
page 9-33 andCruise Control on
page 9-52.

Black plate (71,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Driving and Operating 9-71
7. Stop and have someone pick upand store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11-3. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
If the vehicle is bi-fuel, see the
bi-fuel supplement. Do not tow a trailer during break-in.
See
New Vehicle Break-In on
page 9-23 for more information.
{Warning
The driver can lose control when
pulling a trailer if the correct
equipment is not used or the
vehicle is not driven properly. For
example, if the trailer is too
heavy, the brakes may not work
well or even at all. The driver and
passengers could be seriously
injured. The vehicle may also be
damaged; the resulting repairs
would not be covered by the
vehicle warranty. Pull a trailer
only if all the steps in this section
have been followed. Ask your
dealer for advice and information
about towing a trailer with the
vehicle.
{Caution
Pulling a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To pull a trailer
correctly, follow the advice in this
section and see your dealer for
important information about
towing a trailer with the vehicle.
See Vehicle Load Limits on
page 9-15 for more information
about the vehicle's maximum load
capacity.
To identify the trailering capacity of
the vehicle, read the information in
“Weight of the Trailer” later in this
section.