maintenance GMC SIERRA DENALI 2020 Owner's Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 361
For vehicles equipped with the Stop/
Start system:1. Install the negative battery cable to the battery
sensor stud.
2. Install the negative battery cable nut to the battery sensor
stud and tighten.
3. Turn the ignition on.
For vehicles not equipped with the
Stop/Start system: 1. Install the negative battery cable clamp to the negative
battery post.
2. Tighten the negative battery cable nut.
3. Turn the ignition on.
Four-Wheel Drive
Transfer Case
When to Check Lubricant
Refer to Maintenance Schedule
0 441 to determine when to check
the lubricant.
1. Fill Plug
2. Drain Plug
To get an accurate reading, the
vehicle should be on a level
surface.
If the level is below the bottom of
the fill plug (1) hole, located on the
transfer case, some lubricant will
need to be added. Add enough
lubricant to raise the level to the
bottom of the fill plug (1) hole. Use
care not to overtighten the plug. When to Change Lubricant
Refer to
Maintenance Schedule
0 441 to determine how often to
change the lubricant.
What to Use
Refer to Recommended Fluids and
Lubricants 0452 to determine what
kind of lubricant to use.
Front Axle
When to Check Lubricant
It is not necessary to regularly
check the front axle fluid unless a
leak is suspected or an unusual
noise is heard. A fluid loss could
indicate a problem. Have it
inspected and repaired. This service
can be complex. See your dealer.
Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the fluid. Contaminated
fluid will decrease the life of the
transfer case and/or drive axles and
should be replaced.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
362 Vehicle Care
Rear Axle
When to Check Lubricant
It is not necessary to regularly
check the rear axle fluid unless a
leak is suspected or an unusual
noise is heard. A fluid loss could
indicate a problem. Have it
inspected and repaired. This service
can be complex. See your dealer.
Do not directly power wash the
transfer case and/or front/rear axle
output seals. High pressure water
can overcome the seals and
contaminate the fluid. Contaminated
fluid will decrease the life of the
transfer case and/or drive axles and
should be replaced.
Noise Control System
NOISE EMISSIONS
WARRANTY
General Motors LLC, warrants to the
first person who purchases this
vehicle for purposes other than
resale and to each subsequent
purchaser that this vehicle as
manufactured by General MotorsLLC, was designed, built and
equipped to conform at the time it
left General Motors LLC’s control
with all applicable U.S. EPA Noise
Control Regulations. This warranty
covers this vehicle as designed,
built and equipped by General
Motors LLC, and is not limited to
any particular part, component or
system of the vehicle manufactured
by General Motors LLC. Defects in
design, assembly or in any part,
component or system of the vehicle
as manufactured by General Motors
LLC, which, at the time it left
General Motors LLC’
s control,
caused noise emissions to exceed
Federal standards, are covered by
this warranty for the life of the
vehicle.
TAMPERING WITH NOISE
CONTROL SYSTEM
PROHIBITED
Federal law prohibits the following
acts or the causing thereof:
1. The removal or rendering inoperative by any person,
other than for purposes of maintenance, repair,
or replacement, of any device
or element of design
incorporated into any new
vehicle for the purpose of noise
control prior to its sale or
delivery to the ultimate
purchaser or while it is in
use; or
2. the use of the vehicle after such device or element of
design has been removed or
rendered inoperative by any
person.
Among those acts presumed to
constitute tampering are the acts
listed below.
Insulation:
Removal of the noise shields or any
undercab insulation.
Engine:
Removal or rendering engine speed
governor, if so equipped, inoperative
so as to allow engine speed to
exceed manufacturer specifications.
Modification of the engine control
system or calibration.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
364 Vehicle Care
The ignition key should come out
only when the ignition is off. Contact
your dealer if service is required.
Park Brake and P (Park)
Mechanism Check
{Warning
When you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake.
. To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.
. To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement
Windshield wiper blades should be
replaced periodically. See
Maintenance Schedule 0441.
Replacement blades come in
different types and are removed in
different ways. For proper type and
length, see Maintenance
Replacement Parts 0454.
Caution
Allowing the wiper arm to touch
the windshield when no wiper
blade is installed could damage
the windshield. Any damage that
occurs would not be covered by
the vehicle warranty. Do not allow
the wiper arm to touch the
windshield.
Front Wiper Blade
Replacement
To replace the wiper blade:
1. Pull the wiper assembly away from the windshield.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
366 Vehicle Care
Caution
Do not apply tape or hang any
objects from gas struts. Also do
not push down or pull on gas
struts. This may cause damage to
the vehicle.
See Maintenance Schedule 0441.
Hood
Trunk
Liftgate
Headlamp Aiming
Front Headlamp Aiming
Headlamp aim has been preset and
should need no further adjustment.
If the vehicle is damaged in a crash,
the headlamp aim may be affected.
If adjustment to the headlamps is
necessary, see your dealer.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
390 Vehicle Care
tread life, and may affect the
vehicle's handling and stopping
ability.
Please note that the TPMS is not a
substitute for proper tire
maintenance, and it is the driver's
responsibility to maintain correct tire
pressure, even if under-inflation has
not reached the level to trigger
illumination of the TPMS low tire
pressure telltale.
Your vehicle has also been
equipped with a TPMS malfunction
indicator to indicate when the
system is not operating properly.
The TPMS malfunction indicator is
combined with the low tire pressure
telltale. When the system detects a
malfunction, the telltale will flash for
approximately one minute and then
remain continuously illuminated.
This sequence will continue upon
subsequent vehicle start-ups as
long as the malfunction exists.
When the malfunction indicator is
illuminated, the system may not be
able to detect or signal low tire
pressure as intended. TPMS
malfunctions may occur for a varietyof reasons, including the installation
of replacement or alternate tires or
wheels on the vehicle that prevent
the TPMS from functioning properly.
Always check the TPMS malfunction
telltale after replacing one or more
tires or wheels on your vehicle to
ensure that the replacement or
alternate tires and wheels allow the
TPMS to continue to function
properly.
See
Tire Pressure Monitor
Operation 0390.
See Radio Frequency Statement
0 472.
Tire Pressure Monitor
Operation
This vehicle may have a Tire
Pressure Monitor System (TPMS).
The TPMS is designed to warn the
driver when a low tire pressure
condition exists. TPMS sensors are
mounted onto each tire and wheel
assembly, excluding the spare tire
and wheel assembly. The TPMS
sensors monitor the air pressure in the tires and transmit the tire
pressure readings to a receiver
located in the vehicle.
When a low tire pressure condition
is detected, the TPMS illuminates
the low tire pressure warning light
located on the instrument cluster.
If the warning light comes on, stop
as soon as possible and inflate the
tires to the recommended pressure
shown on the Tire and Loading
Information label. See
Vehicle Load
Limits 0200.
A message to check the pressure in
a specific tire displays in the Driver
Information Center (DIC). The low
tire pressure warning light and the
DIC warning message come on at
each ignition cycle until the tires are
inflated to the correct inflation
pressure. If the vehicle has DIC
buttons, tire pressure levels can be

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 391
viewed. For additional information
and details about the DIC operation
and displays, seeDriver Information
Center (DIC) (Base Level) 0147 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0148.
The low tire pressure warning light
may come on in cool weather when
the vehicle is first started, and then
turn off as the vehicle is driven. This
could be an early indicator that the
air pressure is getting low and
needs to be inflated to the proper
pressure.
A Tire and Loading Information label
shows the size of the original
equipment tires and the correct
inflation pressure for the tires when
they are cold. See Vehicle Load
Limits 0200, for an example of the
Tire and Loading Information label
and its location. Also see Tire
Pressure 0387.
The TPMS can warn about a low
tire pressure condition but it does
not replace normal tire
maintenance. See Tire Inspection
0 396, Tire Rotation 0396 and
Tires 0379.Caution
Tire sealant materials are not all
the same. A non-approved tire
sealant could damage the TPMS
sensors. TPMS sensor damage
caused by using an incorrect tire
sealant is not covered by the
vehicle warranty. Always use only
the GM approved tire sealant
available through your dealer or
included in the vehicle.
TPMS Malfunction Light and
Message
The TPMS will not function properly
if one or more of the TPMS sensors
are missing or inoperable. When the
system detects a malfunction, the
low tire pressure warning light
flashes for about one minute and
then stays on for the remainder of
the ignition cycle. A DIC warning
message also displays. The
malfunction light and DIC warning
message come on at each ignition cycle until the problem is corrected.
Some of the conditions that can
cause these to come on are:
.
One of the road tires has been
replaced with the spare tire. The
spare tire does not have a
TPMS sensor. The malfunction
light and the DIC message
should go off after the road tire
is replaced and the sensor
matching process is performed
successfully. See "TPMS Sensor
Matching Process" later in this
section.
. The TPMS sensor matching
process was not done or not
completed successfully after
rotating the tires. The
malfunction light and the DIC
message should go off after
successfully completing the
sensor matching process. See
"TPMS Sensor Matching
Process" later in this section.
. One or more TPMS sensors are
missing or damaged. The
malfunction light and the DIC
message should go off when the
TPMS sensors are installed and

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
396 Vehicle Care
successfully completing the
sensor learning process. See
"TTPMS Sensor Learning
Process" underTrailering App
0 310.
. One or more TTPMS sensors
are missing or damaged. The
DIC message should go off
when the TTPMS sensors are
installed and the sensor learning
process is performed
successfully. See "TTPMS
Sensor Learning Process" under
Trailering App 0310.
. Operating electronic devices or
being near facilities using radio
wave frequencies similar to the
TTPMS could cause interference
to the TTPMS which could
cause loss of signal reception
from the sensor.
. If the system does not receive
the signal from an individual
sensor, an error message may
not occur until the vehicle has
been driver for a period of time. If the TTPMS is not functioning
properly, it cannot detect or signal a
low tire condition. See your dealer
for service if the DIC message
comes on and stays on when the
trailer tire pressures have been
checked and determined to be
correct.
Tire Inspection
We recommend that the tires,
including the spare tire, if the
vehicle has one, be inspected
for signs of wear or damage at
least once a month.
Replace the tire if:
.The indicators at three or
more places around the tire
can be seen.
.There is cord or fabric
showing through the tire's
rubber.
.The tread or sidewall is
cracked, cut, or snagged
deep enough to show cord or
fabric.
.The tire has a bump, bulge,
or split.
.The tire has a puncture, cut,
or other damage that cannot
be repaired well because of
the size or location of the
damage.
Tire Rotation
Tires should be rotated every
12 000 km (7,500 mi). See
Maintenance Schedule
0441.
Tires are rotated to achieve a
more uniform wear for all tires.
The first rotation is the most
important.
Anytime unusual wear is
noticed, rotate the tires as soon
as possible, check for proper tire
inflation pressure, and check for
damaged tires or wheels. If the
unusual wear continues after the
rotation, check the wheel
alignment. See When It Is Time
for New Tires 0399 and
Wheel Replacement 0403.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 397
Use this rotation pattern when
rotating the tires if the vehicle
has single rear wheels.
Dual Tire Rotation
When the vehicle is new,
or whenever a wheel, wheel
bolt, or wheel nut is replaced or
serviced, check the wheel nut
torque after 160, 1 600, and
10 000 km (100, 1,000, and
6,000 mi) of driving. For proper
torque and wheel nut tightening
information, see“Removing the
Flat Tire and Installing the Spare
Tire” under Tire Changing 0407 and
“Wheel Nut Torque” under
Capacities and Specifications
0 458 and “Removing the Flat
Tire and Installing the Spare
Tire” under Tire Changing 0407.
The outer tire on a dual wheel
setup generally wears faster
than the inner tire. Tires last
longer and wear more evenly if
they are rotated. See Tire
Inspection 0396 and
Tire Rotation 0396. Also see
Maintenance Schedule 0441.
{Warning
If the vehicle is operated with a
tire that is underinflated, the tire
can overheat. An overheated tire
can lose air suddenly or catch
fire. You or others could be
injured. Properly inflate all tires,
including the spare.
See Tire Pressure 0387, for
information on proper tire
inflation.
Use this rotation pattern when
rotating the tires if the vehicle
has dual rear wheels (except
polished forged aluminum
wheels).
Vehicles with polished forged
aluminum dual wheels have
three unique wheels; a front, a
rear outer and a rear inner.
These wheels cannot be rotated
to another position, however,
they can be rotated from left to
right to the same position.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 399
If the full-size tire is part of the
tire rotation, make sure the tire
rotated into the spare position is
stored securely. Push, pull, and
then try to rotate or turn the tire.
If it moves, use the wheel
wrench/hoist shaft to tighten the
cable. SeeTire Changing 0407.
When It Is Time for New
Tires
Factors, such as maintenance,
temperatures, driving speeds,
vehicle loading, and road conditions
affect the wear rate of the tires.
Treadwear indicators are one way to
tell when it is time for new tires.
Treadwear indicators appear when
the tires have only 1.6 mm (1/16 in)
or less of tread remaining. Some
commercial truck tires may not have
treadwear indicators. See Tire
Inspection 0396 and
Tire Rotation 0396 for additional
information.
The rubber in tires ages over time.
This also applies to the spare tire,
if the vehicle has one, even if it is
never used. Multiple factors
including temperatures, loading
conditions, and inflation pressure
maintenance affect how fast aging
takes place. GM recommends that
tires, including the spare if
equipped, be replaced after six
years, regardless of tread wear. To
identify the age of a tire, use the tire
manufacture date which is the last
four digits of the DOT Tire
Identification Number (TIN) which is
molded into one side of the tire
sidewall. The first two digits
represent the week (01-52) and the
last two digits, the year. For example, the third week of the year
2010 would have a four-digit DOT
date of 0310.
Vehicle Storage
Tires age when stored normally
mounted on a parked vehicle. Park
a vehicle that will be stored for at
least a month in a cool, dry, clean
area away from direct sunlight to
slow aging. This area should be free
of grease, gasoline, or other
substances that can deteriorate
rubber.
Parking for an extended period can
cause flat spots on the tires that
may result in vibrations while
driving. When storing a vehicle for
at least a month, remove the tires or
raise the vehicle to reduce the
weight from the tires.
Buying New Tires
GM has developed and matched
specific tires for the vehicle. The
original equipment tires installed
were designed to meet General
Motors Tire Performance Criteria

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
400 Vehicle Care
Specification (TPC Spec)
system rating. When
replacement tires are needed,
GM strongly recommends
buying tires with the same TPC
Spec rating.
GM's exclusive TPC Spec
system considers over a dozen
critical specifications that impact
the overall performance of the
vehicle, including brake system
performance, ride and handling,
traction control, and tire
pressure monitoring
performance. GM's TPC Spec
number is molded onto the tire's
sidewall near the tire size. If the
tires have an all-season tread
design, the TPC Spec number
will be followed by MS for mud
and snow. SeeTire Sidewall
Labeling 0381 for additional
information.
GM recommends replacing worn
tires in complete sets of four (six
for dual rear wheels). Uniform tread depth on all tires will help
to maintain the performance of
the vehicle. Braking and
handling performance may be
adversely affected if all the tires
are not replaced at the same
time. If proper rotation and
maintenance have been done,
all four tires (six for dual rear
wheels) should wear out at
about the same time. See
Tire
Rotation 0396 for information
on proper tire rotation. However,
if it is necessary to replace only
one axle set of worn tires, place
the new tires on the rear axle
(two for single rear wheels, four
for dual rear wheels).
{Warning
Tires could explode during
improper service. Attempting
to mount or dismount a tire
could cause injury or death.
(Continued)
Warning (Continued)
Only your dealer or authorized
tire service center should
mount or dismount the tires.
{Warning
Mixing tires of different sizes,
tread patterns, or types on the
same axle may cause loss of
control of the vehicle, resulting
in a crash or other vehicle
damage. Use the same size,
load range, and type of tires
as the original tires.
This vehicle may have a
different size spare than the
road tires originally installed
on the vehicle. When new, the
vehicle included a spare tire
and wheel assembly with a
similar overall diameter as the
road tires and wheels, so it is
(Continued)