
GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 283
system warning light will flash and a
chime will sound warning you that
the parking brake is still on.
If you are towing a trailer and are
parking on a hill, seeDriving
Characteristics and Towing
Tips 0304.
Brake Assist
The Brake Assist feature is
designed to assist the driver in
stopping or decreasing vehicle
speed in emergency driving
conditions. This feature uses the
stability system hydraulic brake
control module to supplement the
power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle. The
stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsation or
pedal movement during this time is
normal and the driver should
continue to apply the brake pedal as the driving situation dictates. The
Brake Assist feature will
automatically disengage when the
brake pedal is released or brake
pedal pressure is quickly
decreased.
Hill Start Assist (HSA)
This vehicle has a Hill Start Assist
(HSA) feature, which may be useful
when the vehicle is stopped on a
grade. This feature is designed to
prevent the vehicle from rolling,
either forward or rearward, during
vehicle drive off. After you
completely stop and hold the vehicle
in a complete standstill on a grade,
HSA will automatically activate.
During the transition period between
when you release the brake pedal
and start to accelerate to drive off
on a grade, HSA holds the braking
pressure for a maximum of
two seconds to ensure that there is
no rolling. The brakes will
automatically release when the
accelerator pedal is applied within
the two-second window. If the
vehicle is equipped with the
Integrated Trailer Brake Control(ITBC) system, HSA may also apply
the trailer brakes. It will not activate
if the vehicle is in a drive gear and
facing downhill or if the vehicle is
facing uphill and in R (Reverse).
There may be situations on minor
hills (less than 5% grade) with a
loaded vehicle or while pulling a
trailer where HSA may activate.
If you release the brake pedal and
then reapply the brake pedal while
HSA is activated, the brake pedal
typically feels firmer with less pedal
travel.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 285
maintaining control. The vehicle is
safe to drive, but driving should be
adjusted accordingly.
If
dcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.
Drive the vehicle. If
dcomes on
and stays on, the vehicle may need
more time to diagnose the problem.
If the condition persists, see your
dealer.
Turning the Systems Off
and On
The button for TCS and StabiliTrak
is on the center stack.
Caution
Do not repeatedly brake or
accelerate heavily when TCS is
off. The vehicle driveline could be
damaged.
To turn off only TCS, press and
release
g. The traction off lighti
displays in the instrument cluster.
The appropriate message will
display in the DIC. See Ride Control
System Messages 0149. To turn
TCS on again, press and release
g.
The traction off light
idisplayed in
the instrument cluster will turn off.
If TCS is limiting wheel spin when
g
is pressed, the system will not turn
off until the wheels stop spinning.
To turn off both TCS and StabiliTrak,
press and hold
guntil the traction
off light
iand the StabiliTrak OFF
light
gcome on and stay on in the
instrument cluster, then release. The appropriate message will display in
the DIC. See
Ride Control System
Messages 0149.
To turn TCS and StabiliTrak on
again, press and release
g. The
traction off light
iand the
StabiliTrak OFF light
gin the
instrument cluster turn off.
StabiliTrak will automatically turn on
if the vehicle exceeds 56 km/h
(35 mph). Traction control will
remain off.
The vehicle has a Trailer Sway
Control (TSC) feature and a Hill
Start Assist (HSA) feature. See
Trailer Sway Control (TSC) 0333 or
Hill Start Assist (HSA) 0283.
Adding accessories can affect the
vehicle performance. See
Accessories and
Modifications 0341.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 303
Warning (Continued)
.Fuel can spray out if the
refueling nozzle is inserted
too quickly. This spray can
happen if the tank is nearly
full, and is more likely in hot
weather. Insert the refueling
nozzle slowly and wait for
any hiss noise to stop prior
to beginning to flow fuel.
The vehicle has a capless refueling
system and does not have a fuel
cap. The filling nozzle must be fully
inserted and latched prior to starting
fuel flow.
{Warning
Overfilling the fuel tank by more
than three clicks of a standard fill
nozzle may cause:
. Vehicle performance issues,
including engine stalling and
damage to the fuel system.
. Fuel spills.
. Potential fuel fires.
Be careful not to spill fuel. Wait a
few seconds after you have finished
pumping before removing the
nozzle. Clean fuel from painted
surfaces as soon as possible. See
Exterior Care 0427.
{Warning
If a fire starts while you are
refueling, do not remove the
nozzle. Shut off the flow of fuel by
shutting off the pump or by
notifying the station attendant.
Leave the area immediately. For models with dual fuel tanks, the
fuel gauge shows an average of
both tanks. The rear tank is emptied
first. When refueling, refuel the front
tank first, then add fuel to the
rear tank.
Filling the Tank With a Portable
Gas Can
If the vehicle runs out of fuel and
must be filled from a portable
gas can:
1. Locate the capless funnel
adapter from inside the vehicle.
2. Insert and latch the funnel into the capless fuel system.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Driving and Operating 307
If parking the rig on a hill:1. Press the brake pedal, but do not shift into P (Park) yet. Turn
the wheels into the curb if
facing downhill or into traffic if
facing uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular
brakes until the chocks absorb
the load.
4. Reapply the brake pedal. Then apply the parking brake and
shift into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks. 7. Stop and have someone pick
up and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule 0438.
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 0258.
{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
or the trailer brakes are
inadequate for the load, the
vehicle may not stop as expected.
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
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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Vehicle Care 339
Vehicle Care
General Information
General Information . . . . . . . . . . 340
California Proposition65 Warning . . . . . . . . . . . . . . . . . 340
California Perchlorate Materials Requirements . . . . . 341
Accessories and Modifications . . . . . . . . . . . . . . . . 341
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 342
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 342
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 343
Engine Oil . . . . . . . . . . . . . . . . . . . . 348
Engine Oil Life System . . . . . . . 351
Automatic Transmission Fluid (6 Speed Transmission) . . . . . 352
Automatic Transmission Fluid (8 Speed Transmission) . . . . . 354
Engine Air Cleaner/Filter . . . . . . 355
Cooling System . . . . . . . . . . . . . . 356
Engine Coolant . . . . . . . . . . . . . . . 357
Engine Overheating . . . . . . . . . . 360
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . 362
Engine Fan . . . . . . . . . . . . . . . . . . . 362 Power Steering Fluid (1500
Series) . . . . . . . . . . . . . . . . . . . . . . 363
Power Steering Fluid (2500/ 3500 Series) . . . . . . . . . . . . . . . . 363
Washer Fluid . . . . . . . . . . . . . . . . . 363
Brakes . . . . . . . . . . . . . . . . . . . . . . . 364
Brake Fluid . . . . . . . . . . . . . . . . . . . 365
Battery - North America . . . . . . 366
Four-Wheel Drive . . . . . . . . . . . . . 367
Front Axle . . . . . . . . . . . . . . . . . . . . 368
Rear Axle . . . . . . . . . . . . . . . . . . . . 368
Noise Control System . . . . . . . . 370
Starter Switch Check . . . . . . . . . 371
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 371
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 371
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 371
Wiper Blade Replacement . . . . 372
Glass Replacement . . . . . . . . . . 372
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 373
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 373
Halogen Bulbs . . . . . . . . . . . . . . . . 373
High Intensity Discharge (HID) Lighting . . . . . . . . . . . . . . . . . . . . . 373 LED Lighting . . . . . . . . . . . . . . . . . 373
Taillamps, Turn Signal,
Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 374
Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 375
Replacement Bulbs . . . . . . . . . . . 375
Electrical System
High Voltage Devices and Wiring . . . . . . . . . . . . . . . . . . . . . . . 376
Electrical System Overload . . . 376
Fuses . . . . . . . . . . . . . . . . . . . . . . . . 376
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 376
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . . . 379
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 381
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 383
All-Season Tires . . . . . . . . . . . . . . 384
Winter Tires . . . . . . . . . . . . . . . . . . 384
Low-Profile Tires . . . . . . . . . . . . . 385
All-Terrain Tires . . . . . . . . . . . . . . . 385
Tire Sidewall Labeling . . . . . . . . 385
Tire Designations . . . . . . . . . . . . . 388
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 389

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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356 Vehicle Care
3. Air Duct Clamp
1. Locate the air cleaner/filterassembly. See Engine
Compartment Overview 0343.
2. Disconnect the outlet duct by loosening the air duct
clamp (3).
3. Disconnect the electrical connectors (2) and the
connector harness from the
cover.
4. Remove the four screws (1) on top of the cover of the housing
and lift up the cover.
5. Remove the engine air cleaner/ filter from the housing. Take
care to dislodge as little dirt as
possible.
6. Clean the engine air cleaner/ filter sealing surfaces and the
housing.
7. Inspect or replace the engine air cleaner/filter.
8. Reverse Steps 2–4 to reinstall the filter cover housing.{Warning
Operating the engine with the air
cleaner/filter off can cause you or
others to be burned. The air
cleaner not only cleans the air; it
helps to stop flames if the engine
backfires. Use caution when
working on the engine and do not
drive with the air cleaner/filter off.
Caution
If the air cleaner/filter is off, dirt
can easily get into the engine,
which could damage it. Always
have the air cleaner/filter in place
when you are driving.
Cooling System
If the vehicle has the Duramax
diesel engine, see the Duramax
diesel supplement.
The cooling system allows the
engine to maintain the correct
working temperature.
5.3L V8 Engine Shown, 4.3L
V6 Engine and 6.2L V8 Engine Similar
1. Coolant Surge Tank
2. Coolant Surge TankPressure Cap
3. Engine Electric Cooling Fans (Out of View)
{Warning
An electric engine cooling fan can
start even when the engine is not
running. To avoid injury, always
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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360 Vehicle Care
4. With the coolant surge tankpressure cap off, start the
engine and let it run until the
engine coolant temperature
gauge indicates approximately
90 °C (195 °F).
By this time, the coolant level
inside the coolant surge tank
may be lower. If the level is
lower, add more of the proper
mixture to the coolant surge
tank until the level reaches the
FULL COLD mark.
5. Replace the pressure cap tightly.
6. Verify coolant level after the engine is shut off and the
coolant is cold. If necessary,
repeat coolant fill procedure
Steps 1–6.
Caution
If the pressure cap is not tightly
installed, coolant loss and
possible engine damage may
occur. Be sure the cap is properly
and tightly secured.
Engine Overheating
If the vehicle has the Duramax
diesel engine, see the Duramax
diesel supplement.
Caution
Running the engine without
coolant may cause damage or a
fire. Vehicle damage would not be
covered by the vehicle warranty.
The vehicle has several indicators
to warn of engine overheating.
There is a coolant temperature
gauge in the vehicle's instrument
cluster. See Engine Coolant
Temperature Gauge 0127.
In addition, there are ENGINE
OVERHEATED STOP ENGINE,
ENGINE OVERHEATED IDLE
ENGINE, and ENGINE POWER IS
REDUCED messages in the Driver
Information Center (DIC). See
Engine Cooling System Messages
0 146 andEngine Power
Messages 0147. If the decision is made not to lift the
hood when this warning appears,
get service help right away. See
Roadside Assistance
Program
0461.
If the decision is made to lift the
hood, make sure the vehicle is
parked on a level surface.
4.3L V6, 5.3L V8, and 6.2L
V8 Engines
Check to see if the engine cooling
fans are running. If the engine is
overheating, the fans should be
running. If they are not, do not
continue to run the engine and have
the vehicle serviced.
If Steam is Coming from the
Engine Compartment
{Warning
Steam from an overheated engine
can burn you badly, even if you
just open the hood. Stay away
from the engine if you see or hear
steam coming from it. Just turn it (Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
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376 Vehicle Care
Electrical System
High Voltage Devices and
Wiring
For an eAssist vehicle, see the
Silverado/Sierra eAssist
supplement.
Electrical System
Overload
The vehicle has fuses to protect
against an electrical system
overload. Fuses also protect power
devices in the vehicle.
Replace a bad fuse with a new one
of the identical size and rating.
If there is a problem on the road and
a fuse needs to be replaced, there
are some spare fuses and a fuse
puller in the Instrument Panel Fuse
Block. The same amperage fuse
can also be borrowed. Choose
some feature of the vehicle that is
not needed to use and replace it as
soon as possible.
Headlamp Wiring
An electrical overload may cause
the lamps to go on and off, or in
some cases to remain off. Have the
headlamp wiring checked right away
if the lamps go on and off or
remain off.
Windshield Wipers
If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses
The wiring circuits in the vehicle are
protected from short circuits by
fuses. This greatly reduces the
chance of fires caused by electrical
problems.
Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.
Fuses of the same amperage can
be temporarily borrowed from
another fuse location, if a fuse goes
out. Replace the fuse as soon as
you can.
Engine Compartment
Fuse Block
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
The engine compartment fuse block
is in the engine compartment, on
the driver side of the vehicle.