2020 GMC SIERRA maintenance

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
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 0442.
Replacement blades come in
different types and are removed in
different ways. For proper type and
length, see Maintenance
Replacement Parts 0455.
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 - 4/10/19
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 0442.
Hood
Trunk
Liftgate
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 - 4/10/19
Vehicle Care 389
Tire Pressure for
High-Speed Operation
{Warning
Driving at high speeds, 160 km/h
(100 mph) or higher, puts
additional strain on tires.
Sustained high-speed driving
causes excessive heat buildup
and can cause sudden tire failure.
This could cause a crash, and
you or others could be killed.
Some high-speed rated tires
require inflation pressure
adjustment for high-speed
operation. When speed limits and
road conditions allow the vehicle
to be driven at high speeds, make
sure the tires are rated for
high-speed operation, are in
excellent condition, and are set to
the correct cold tire inflation
pressure for the vehicle load.
Tire Pressure Monitor
System
The Tire Pressure Monitor System
(TPMS) uses radio and sensor
technology to check tire pressure
levels. The TPMS sensors monitor
the air pressure in your tires and
transmit tire pressure readings to a
receiver located in the vehicle.
Each tire, including the spare (if
provided), should be checked
monthly when cold and inflated to
the inflation pressure recommended
by the vehicle manufacturer on the
vehicle placard or tire inflation
pressure label. (If your vehicle has
tires of a different size than the size
indicated on the vehicle placard or
tire inflation pressure label, you
should determine the proper tire
inflation pressure for those tires.)
As an added safety feature, your
vehicle has been equipped with a
tire pressure monitoring system
(TPMS) that illuminates a low tire
pressure telltale when one or more
of your tires is significantly
under-inflated.Accordingly, when the low tire
pressure telltale illuminates, you
should stop and check your tires as
soon as possible, and inflate them
to the proper pressure. Driving on a
significantly under-inflated tire
causes the tire to overheat and can
lead to tire failure. Under-inflation
also reduces fuel efficiency and tire
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

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 391
inflation pressure for the tires when
they are cold. SeeVehicle 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
the sensor matching process is
performed successfully. See
your dealer for service.
. Replacement tires or wheels do
not match the original equipment
tires or wheels. Tires and wheels
other than those recommended
could prevent the TPMS from
functioning properly. See Buying
New Tires 0399.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
396 Vehicle Care
.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 0442.
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 0398 and
Wheel Replacement 0403.
Use this rotation pattern when
rotating the tires if the vehicle
has single rear wheels.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 397
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
0 459 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 0442.{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 - 4/10/19
398 Vehicle Care
Use this rotation pattern when
rotating the tires if the vehicle
has polished forged aluminum
dual rear wheels. The spare
wheel can be used in any
position in the event of a flat tire,
and can be rotated with the rear
inner wheels. After the flat tire is
repaired, if the spare is not on
one of the inner rear positions, it
must be replaced by the correct
wheel in the front or rear outer
positions.
When installing dual wheels,
check that the vent holes in the
inner and outer wheels on each
side are lined up.
Adjust the front and rear tires to
the recommended inflation
pressure on the Tire and
Loading Information label after
the tires have been rotated. See
Tire Pressure0387 and
Vehicle Load Limits 0200. Check that all wheel nuts are
properly tightened. See
“Wheel
Nut Torque” underCapacities
and Specifications 0459, and
“Removing the Flat Tire and
Installing the Spare Tire” under
Tire Changing 0407.
{Warning
Rust or dirt on a wheel, or on the
parts to which it is fastened, can
make wheel nuts become loose
after time. The wheel could come
off and cause a crash. When
changing a wheel, remove any
rust or dirt from places where the
wheel attaches to the vehicle. In
an emergency, a cloth or a paper
towel can be used; however, use
a scraper or wire brush later to
remove all rust or dirt.
Lightly coat the inner diameter of
the wheel hub opening with
wheel bearing grease after a
wheel change or tire rotation to
prevent corrosion or rust build-up. Do not get grease on
the flat wheel mounting surface
or on the wheel nuts or bolts.
Reset the Tire Pressure Monitor
System (TPMS), if the vehicle
has one. See
Tire Pressure
Monitor Operation 0390.
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. See Tire 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.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 399
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. SeeTire
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
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