2020 GMC SIERRA DENALI steering

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 277
{Warning
The LDW system does not steer
the vehicle. The LDW system
may not:. Provide enough time to
avoid a crash.
. Detect lane markings under
poor weather or visibility
conditions. This can occur if
the windshield or
headlamps are blocked by
dirt, snow, or ice; if they are
not in proper condition; or if
the sun shines directly into
the camera.
. Detect road edges.
. Detect lanes on winding or
hilly roads.
If LDW only detects lane
markings on one side of the road,
it will only warn you when
departing the lane on the side
where it has detected a lane
marking. Always keep your (Continued)
Warning (Continued)
attention on the road and
maintain proper vehicle position
within the lane, or vehicle
damage, injury, or death could
occur. Always keep the
windshield, headlamps, and
camera sensors clean and in
good repair. Do not use LDW in
bad weather conditions.
How the System Works
LDW utilizes a camera sensor
installed on the windshield ahead of
the rearview mirror to detect lane
markings.
To turn LDW on and off, press
@on
the instrument panel to the left of
the steering wheel. The control
indicator will light when LDW is on.
When LDW is on,@is green if
LDW is available to warn of a lane
departure. If the vehicle crosses a
detected lane marking without using
the turn signal in that direction,
@
changes to amber and flashes.
Additionally, there will be three
beeps, on the right or left,
depending on the lane departure
direction. LDW will not alert if the
turn signal is active in the direction
of lane departure or if LDA detects
that you are accelerating, braking or
actively steering.
When the System Does Not
Seem to Work Properly
The system may not detect lanes as
well when there are:
. Close vehicles ahead.
. Sudden lighting changes, such
as when driving through tunnels.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
278 Driving and Operating
.Banked roads.
If the LDW system is not functioning
properly when lane markings are
clearly visible, cleaning the
windshield may help.
LDW alerts may occur due to tar
marks, shadows, cracks in the road,
temporary or construction lane
markings, or other road
imperfections. This is normal system
operation; the vehicle does not need
service. Turn LDW off if these
conditions continue.
Lane Keep Assist (LKA)
(1500 Series)
If equipped, LKA may help avoid
crashes due to unintentional lane
departures. This system uses a
camera to detect lane markings
between 60 km/h (37 mph) and
180 km/h (112 mph). It may assist
by gently turning the steering wheel
if the vehicle approaches a detected
lane marking. It may also provide a
Lane Departure Warning (LDW)
alert if the vehicle crosses a
detected lane marking. LKA can be overridden by turning the steering
wheel. This system is not intended
to keep the vehicle centered in the
lane. LKA will not assist and alert if
the turn signal is active in the
direction of lane departure, or if it
detects that you are accelerating,
braking or actively steering.
{Warning
The LKA system does not
continuously steer the vehicle.
It may not keep the vehicle in the
lane or give a Lane Departure
Warning (LDW) alert, even if a
lane marking is detected.
The LKA and LDW systems
may not:
. Provide an alert or enough
steering assist to avoid a
lane departure or crash.
. Detect lane markings under
poor weather or visibility
conditions. This can occur if
the windshield or
headlamps are blocked by
(Continued)
Warning (Continued)
dirt, snow, or ice; if they are
not in proper condition; or if
the sun shines directly into
the camera.
. Detect road edges.
. Detect lanes on winding or
hilly roads.
If LKA only detects lane markings
on one side of the road, it will
only assist or provide an LDW
alert when approaching the lane
on the side where it has detected
a lane marking. Even with LKA
and LDW, you must steer the
vehicle. Always keep your
attention on the road and
maintain proper vehicle position
within the lane, or vehicle
damage, injury, or death could
occur. Always keep the
windshield, headlamps, and
camera sensors clean and in
good repair. Do not use LKA in (Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 279
Warning (Continued)
bad weather conditions or on
roads with unclear lane markings,
such as construction zones.
{Warning
Using LKA while towing a trailer
or on slippery roads could cause
loss of control of the vehicle and
a crash. Turn the system off.
How the System Works
LKA uses a camera sensor installed
on the windshield ahead of the
rearview mirror to detect lane
markings. It may provide brief
steering assist if it detects an
unintended lane departure. It may
further provide an audible alert or
the driver seat may pulse indicating
that a lane marking has been
crossed.To turn LKA on and off, press
A
on the center stack. If equipped, the
indicator light on the button comes
on when LKA is on and turns off
when LKA is disabled.
When on,
Ais white, if equipped,
indicating that the system is not
ready to assist.
Ais green if LKA
is ready to assist. LKA may assist
by gently turning the steering wheel
if the vehicle approaches a detected
lane marking.
Ais amber when
assisting. It may also provide a
Lane Departure Warning (LDW)
alert by flashing
Aamber if the
vehicle crosses a detected lane
marking. Additionally, there may be
three beeps, or the driver seat may
pulse three times, on the right or
left, depending on the lane
departure direction. Take Steering
The LKA system does not
continuously steer the vehicle.
If LKA does not detect active driver
steering, an alert and chime may be
provided. Steer the vehicle to
dismiss. LKA may become
temporarily unavailable after
repeated take steering alerts.
When the System Does Not
Seem to Work Properly
The system performance may be
affected by:
.
Close vehicles ahead.
. Sudden lighting changes, such
as when driving through tunnels.
. Banked roads.
. Roads with poor lane markings,
such as two-lane roads.
If the LKA system is not functioning
properly when lane markings are
clearly visible, cleaning the
windshield may help.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Driving and Operating 289
unexpected or unsafe manner.
Before driving, inspect all trailer
hitch parts and attachments, safety
chains, electrical connectors, lamps,
tires, and mirrors. SeeTowing
Equipment 0296. If the trailer has
electric brakes, start the
combination moving and then
manually apply the trailer brake
controller to check that the trailer
brakes work. During the trip,
occasionally check that the cargo
and trailer are secure and that the
lamps and any trailer brakes are
working.
Towing with a Stability Control
System
When towing, the stability control
system might be heard. The system
reacts to vehicle movement caused
by the trailer, which mainly occurs
during cornering. This is normal
when towing heavier trailers.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving without a trailer. This can
help to avoid heavy braking and
sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination of the vehicle and
trailer will not accelerate as quickly
and is much longer than the vehicle
alone. It is necessary to go much
farther beyond the passed vehicle
before returning to the lane. Pass
on level roadways. Avoid passing
on hills if possible.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move that hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making Turns
Caution
Turn more slowly and make wider
arcs when towing a trailer to
prevent damage to your vehicle.
Making very sharp turns could
cause the trailer to contact the
vehicle.
Make wider turns than normal when
towing, so the trailer will not go over
soft shoulders, over curbs, or strike
road signs, trees, or other objects.
Always signal turns well in advance.
Do not steer or brake suddenly.
Driving on Grades
Reduce speed and shift to a lower
gear before starting down a long or
steep downhill grade. If the
transmission is not shifted down, the
brakes may overheat and result in
reduced braking efficiency.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
304 Driving and Operating
lamp circuits on the trailer. DIC
messages and Trailering App alerts
may be displayed if lighting circuit
issues are detected on the trailer.
Pressing START LIGHT TEST in the
Trailering App automatically
activates the trailer lamps. The
Trailering App is not a substitute for
manually inspecting your trailer
lamps. SeeTrailering App 0310.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing
lanes, or stopping. When towing a
trailer, the arrows on the instrument
cluster will illuminate even if the
trailer is not properly connected or
the bulbs are burned out.
Tow/Haul Mode
For instructions on how to enter
Tow/Haul Mode, see Driver Mode
Control 0238.
Tow/Haul assists when pulling a
heavy trailer or a large or heavy
load. See Tow/Haul Mode 0227. Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See
“Trailer Weight ”under Trailer
Towing 0292.
Tow/Haul Mode is most useful when
towing a heavy trailer or carrying a
large or heavy load:
. Through rolling terrain.
. In stop-and-go traffic.
. In busy parking lots.
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage;
however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics,
heavy or light steering efforts, and
reduced fuel economy.Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer brake systems. These instructions
apply to both types of electric trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is proportional to
the amount of vehicle braking. This
available power output to the trailer
brakes can be adjusted to a wide
range of trailering situations.
The ITBC system is integrated with
the vehicle’
s brake, antilock brake,
and StabiliTrak/Electronic Stability
Control (ESC) systems. In trailering
conditions that cause the vehicle’s
antilock brake or StabiliTrak/ESC
systems to activate, power sent to
the trailer's brakes will be
automatically adjusted to minimize

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 327
Vehicle Care
General Information
General Information . . . . . . . . . . 328
California Proposition65 Warning . . . . . . . . . . . . . . . . . 329
California Perchlorate Materials Requirements . . . . . 329
Accessories and Modifications . . . . . . . . . . . . . . . . 329
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 330
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 330
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 332
Engine Oil . . . . . . . . . . . . . . . . . . . . 339
Engine Oil Life System . . . . . . . 341
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . 343
Engine Air Filter Life System . . . . . . . . . . . . . . . . . . . . . . 343
Engine Air Cleaner/Filter . . . . . . 344
Cooling System . . . . . . . . . . . . . . 346
Engine Overheating . . . . . . . . . . 351
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . 352
Engine Fan . . . . . . . . . . . . . . . . . . . 353 Power Steering Fluid . . . . . . . . . 354
Washer Fluid . . . . . . . . . . . . . . . . . 354
Brakes . . . . . . . . . . . . . . . . . . . . . . . 355
Brake Pad Life System . . . . . . . 356
Brake Fluid . . . . . . . . . . . . . . . . . . . 357
Battery - North America . . . . . . 358
Four-Wheel Drive . . . . . . . . . . . . . 361
Front Axle . . . . . . . . . . . . . . . . . . . . 361
Rear Axle . . . . . . . . . . . . . . . . . . . . 362
Noise Control System . . . . . . . . 362
Starter Switch Check . . . . . . . . . 363
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 363
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 363
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 364
Wiper Blade Replacement . . . . 364
Windshield Replacement . . . . . 365
Gas Strut(s) . . . . . . . . . . . . . . . . . . 365
Headlamp Aiming
Front Headlamp Aiming . . . . . . 366
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 367
Halogen Bulbs . . . . . . . . . . . . . . . . 367
LED Lighting . . . . . . . . . . . . . . . . . 367 Headlamps, Front Turn Signal,
Sidemarker, and Parking
Lamps . . . . . . . . . . . . . . . . . . . . . . 367
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 368
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 369
License Plate Lamp . . . . . . . . . . 369
Electrical System
Electrical System Overload . . . 370
Fuses and Circuit Breakers . . . 370
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 371
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . . . 374
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 376
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 379
All-Season Tires . . . . . . . . . . . . . . 379
Winter Tires . . . . . . . . . . . . . . . . . . 380
Low-Profile Tires . . . . . . . . . . . . . 380
All-Terrain Tires . . . . . . . . . . . . . . . 381
Tire Sidewall Labeling . . . . . . . . 381
Tire Designations . . . . . . . . . . . . . 383
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 385

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 339
1. Remote Negative (–) Location.See Jump Starting - North
America 0419.
2. Positive (+) Terminal (Under Cover). See Jump Starting -
North America 0419.
3. Battery - North America 0358.
4. Engine Air Cleaner/Filter 0344.
5. Engine Oil Dipstick. See “Checking Engine Oil” under
Engine Oil 0339.
6. Engine Cooling Fan (Out of View). See Cooling System
0 346.
7. Power Steering Fluid Reservoir. See Power Steering
Fluid 0354.
8. Engine Oil Fill Cap. See “When
to Add Engine Oil” under
Engine Oil 0339.
9. Auxiliary Battery. Battery -
North America 0358.
10. Brake Fluid Reservoir. See Brake Fluid 0357.
11. Engine Compartment Fuse
Block 0371. 12. Coolant Surge Tank and
Pressure Cap. See Cooling
System 0346.
13. Windshield Washer Fluid Reservoir. See “Adding Washer
Fluid” under Washer Fluid
0 354.
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
Engine Oil
For diesel engine vehicles, see
“Engine Oil” in the Duramax diesel
supplement.
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
. Use engine oil approved to the
proper specification and of the
proper viscosity grade. See
“Selecting the Right Engine Oil”
in this section. .
Check the engine oil level
regularly and maintain the
proper oil level. See “Checking
Engine Oil” and“When to Add
Engine Oil” in this section.
. Change the engine oil at the
appropriate time. See Engine Oil
Life System 0341.
. Always dispose of engine oil
properly. See “What to Do with
Used Oil” in this section.Checking Engine Oil
Check the engine oil level regularly,
every 650 km (400 mi), especially
prior to a long trip. The engine oil
dipstick handle is a loop. See
Engine Compartment Overview
0332 for the location.
{Warning
The engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
342 Vehicle Care
include engine revolutions, engine
temperature, and miles driven.
Based on driving conditions, the
mileage at which an oil change is
indicated can vary considerably. For
the oil life system to work properly,
the system must be reset every time
the oil is changed.
On some vehicles, when the system
has calculated that oil life has been
diminished, a CHANGE ENGINE
OIL SOON message comes on to
indicate that an oil change is
necessary. Change the oil as soon
as possible within the next 1 000 km
(600 mi). It is possible that, if driving
under the best conditions, the oil life
system might indicate that an oil
change is not necessary for up to a
year. The engine oil and filter must
be changed at least once a year
and, at this time, the system must
be reset. For vehicles without the
CHANGE ENGINE OIL SOON
message, an oil change is needed
when the REMAINING OIL LIFE
percentage is near 0%. Your dealer
has trained service people who will
perform this work and reset the
system. It is also important to checkthe oil regularly over the course of
an oil drain interval and keep it at
the proper level.
If the system is ever reset
accidentally, the oil must be
changed at 5 000 km (3,000 mi)
since the last oil change.
Remember to reset the oil life
system whenever the oil is changed.
How to Reset the Engine Oil
Life System
Reset the system whenever the
engine oil is changed so that the
system can calculate the next
engine oil change. Always reset the
engine oil life to 100% after every oil
change. It will not reset itself. To
reset the engine oil life system:
1. Display the oil life percentage on the DIC. See Driver
Information Center (DIC) (Base
Level) 0147 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0148.
2. Press the thumbwheel on the steering wheel, or the trip
odometer reset stem if the
vehicle does not have DIC controls, for several seconds.
When the confirmation
message displays, select YES.
The oil life will change
to 100%.
The oil life system can also be reset
as follows:
1. Display the oil life percentage on the DIC. See Driver
Information Center (DIC) (Base
Level) 0147 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0148.
2. Fully press the accelerator pedal slowly three times within
five seconds.
3. If the display changes to 100%, the system is reset.
If the vehicle has a CHANGE
ENGINE OIL SOON message and it
comes back on when the vehicle is
started and/or the oil life percentage
is near 0%, the engine oil life
system has not been reset. Repeat
the procedure.