ECU GMC SIERRA 2020 Owner's Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 103
Rear Center Position
Rear Center Position
2.3. For a top tether in the rear center position: 2.3.1. Remove the driver
side head restraint
and center
headrest. See
“Head Restraint or
Headrest Removal
and Reinstallation”
later in this
section.
2.3.2. Route the top tether (1) through
the center loop (2).
2.3.3. Attach the top tether (1) to the
driver side top
tether metal
anchor (3).
2.3.4. Make sure the child restraint top
tether hook is
completely closed
and secured to the
top tether anchor.
3. Tighten the top tether per the child restraint manufacturer's
instructions. When the top tether is properly
tightened, the loop may bend.
This is normal and will not
damage the vehicle.
If child restraints are installed
in both outboard positions, both
top tethers can be attached to
the center anchor. Top tethers
can be attached for child
restraints in all three rear
seating positions at the same
time, following the routing
instructions above.
4. Before placing a child in the child restraint, make sure it is
securely held in place. To
check, grasp the child restraint
at the LATCH path and attempt
to move it side to side and
back and forth. There should
be no more than 2.5 cm (1 in)
of movement for proper
installation.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
104 Seats and Restraints
Head Restraint or Headrest
Removal and Reinstallation
The second row outboard head
restraints or center headrest can be
removed if they interfere with the
proper installation of the child
restraint.
To remove the second row head
restraints or center headrest:
1. Press both buttons on the headrestraint or headrest posts at
the same time, and pull up on
the head restraint or headrest.
2. Store the head restraint or headrest in a secure place. 3. When the child restraint is
removed, reinstall the head
restraint or headrest before the
seating position is used.
{Warning
With head restraints that are not
installed and adjusted properly,
there is a greater chance that
occupants will suffer a neck/
spinal injury in a crash. Do not
drive until the head restraints for
all occupants are installed and
adjusted properly.
To reinstall the head restraint or
headrest:
1. Insert the head restraint or headrest posts into the holes in
the top of the seatback. The
notches on the posts must face
the driver side of the vehicle.
2. Push the head restraint or headrest down.
3. Try to move the head restraint or headrest to make sure that it
is locked in place.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 105
Replacing LATCH System
Parts After a Crash
{Warning
A crash can damage the LATCH
system in the vehicle. A damaged
LATCH system may not properly
secure the child restraint,
resulting in serious injury or even
death in a crash. To help make
sure the LATCH system is
working properly after a crash,
see your dealer to have the
system inspected and any
necessary replacements made as
soon as possible.
If the vehicle has the LATCH system
and it was being used during a
crash, new LATCH system parts
may be needed.
New parts and repairs may be
necessary even if the LATCH
system was not being used at the
time of the crash.
Securing Child Restraints
(With the Seat Belt in the
Rear Seat)
When securing a child restraint with
the seat belts in a rear seat position,
study the instructions that came with
the child restraint to make sure it is
compatible with this vehicle.
If the child restraint has the LATCH
system, see Lower Anchors and
Tethers for Children (LATCH
System) 092 for how and where to
install the child restraint using
LATCH. If a child restraint is secured
in the vehicle using a seat belt and
it uses a top tether, see Lower
Anchors and Tethers for Children
(LATCH System) 092 for top tether
anchor locations.
Do not secure a child seat in a
position without a top tether anchor
if a national or local law requires
that the top tether be anchored, or if
the instructions that come with the
child restraint say that the top tether
must be anchored. In Canada, the law requires that
forward-facing child restraints have
a top tether, and that the tether be
attached.
If the child restraint or vehicle seat
position does not have the LATCH
system, you will be using the seat
belt to secure the child restraint. Be
sure to follow the instructions that
came with the child restraint.
If more than one child restraint
needs to be installed in the rear
seat, be sure to read
Where to Put
the Restraint 091.
Double Cab
1. Remove the head restraint or
headrest prior to installing a
forward-facing child restraint in
an outboard rear seating
position. See “Head Restraint
or Headrest Removal and
Reinstallation” underLower
Anchors and Tethers for
Children (LATCH System) 092.
2. Put the child restraint on the seat.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 107
7. For forward-facing childrestraints, attach and tighten
the top tether to the top tether
anchor (loop). Refer to the child
restraint instructions, the
vehicle LATCH anchor weight
limits, and instructions listed in
Lower Anchors and Tethers for
Children (LATCH System) 092.
8. Before placing a child in the child restraint, make sure it is
securely held in place. To
check, grasp the child restraint
at the seat belt path and
attempt to move it side to side
and back and forth. When the
child restraint is properly
installed, there should be no
more than 2.5 cm (1 in) of
movement.
To remove the child restraint,
unbuckle the vehicle seat belt and
let it return to the stowed position.
If the top tether is attached to a top
tether anchor, disconnect it.
Reinstall the head restraint or
headrest before the seating position
is used. See “Head Restraint or
Headrest Removal and Reinstallation”
underLower Anchors
and Tethers for Children (LATCH
System) 092 for additional
information on installing the
headrest properly.
Crew Cab
1. Put the child restraint on the seat.
2. Pick up the latch plate, and run the lap and shoulder portions
of the vehicle seat belt through
or around the child restraint.
The child restraint instructions
will show you how.
3. Push the latch plate into thebuckle until it clicks.
Position the release button on
the buckle, away from the child
restraint, so that the seat belt
could be quickly unbuckled if
necessary.
4. Pull the shoulder belt all the
way out of the retractor to set
the lock. When the retractor
lock is set, the belt can be
tightened but not pulled out of
the retractor.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
108 Seats and Restraints
5. To tighten the belt, push downon the child restraint, pull the
shoulder portion of the belt to
tighten the lap portion of the
belt, and feed the shoulder belt
back into the retractor. When
installing a forward-facing child
restraint, it may be helpful to
use your knee to push down on
the child restraint as you
tighten the belt.
Try to pull the belt out of the
retractor to make sure the
retractor is locked. If the
retractor is not locked, repeat
Steps 4 and 5. 6. If the child restraint has a top
tether, follow the child restraint
manufacturer's instructions
regarding the use of the top
tether. See Lower Anchors and
Tethers for Children (LATCH
System) 092 for more
information on using the top
tether anchors.
7. Before placing a child in the child restraint, make sure it is
securely held in place. To
check, grasp the child restraint
at the seat belt path and
attempt to move it side to side
and back and forth. When the
child restraint is properly
installed, there should be no
more than 2.5 cm (1 in) of
movement.
To remove the child restraint,
unbuckle the vehicle seat belt and
let it return to the stowed position.
If the top tether is attached to a top
tether anchor, disconnect it.
For outboard rear seating positions,
if the child restraint cannot be
installed properly with the head
restraint in place, the head restraint may be removed. See your dealer
for assistance with removal, and
store the removed head restraint in
a secure place. When the child
restraint is removed, reinstall the
head restraint before the seating
position is used. For reinstallation
instructions, see
“Head Restraint or
Headrest Removal and
Reinstallation” underLower Anchors
and Tethers for Children (LATCH
System) 092.Securing Child Restraints
(In the Center Front Seat)
{Warning
A child in a child restraint in the
center front seat can be badly
injured or killed by the frontal
airbags if they inflate. Never
secure a child restraint in the
center front seat. It is always
better to secure a child restraint in
a rear seat.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 109
Do not use child restraints in the
center front seat position.
Securing Child Restraints
(With the Seat Belt in the
Front Outboard Seat)
This vehicle has airbags. A rear
seat is a safer place to secure a
forward-facing child restraint. See
Where to Put the Restraint091.
In addition, the vehicle has a
passenger sensing system which is
designed to turn off the front
outboard passenger frontal airbag
under certain conditions. See
Passenger Sensing System 078
and
Passenger Airbag Status Indicator
0 137 for more information,
including important safety
information.
Never put a rear-facing child
restraint in the front. This is because
the risk to the rear-facing child is so
great, if the airbag deploys.
{Warning
A child in a rear-facing child
restraint can be seriously injured
or killed if the front outboard
passenger frontal airbag inflates.
This is because the back of the
rear-facing child restraint would
be very close to the inflating
airbag. A child in a forward-facing
child restraint can be seriously
injured or killed if the front
outboard passenger frontal airbag
inflates and the passenger seat is
in a forward position.
Even if the passenger sensing
system has turned off the front
outboard passenger frontal
airbag, no system is fail-safe. No
one can guarantee that an airbag
will not deploy under some
unusual circumstance, even
though it is turned off.
Secure rear-facing child restraints
in a rear seat, even if the airbag
is off. If you secure a
(Continued)
Warning (Continued)
forward-facing child restraint in
the front outboard passenger
seat, always move the seat as far
back as it will go. It is better to
secure the child restraint in a
rear seat.
SeePassenger Sensing System
0 78 for additional information.
If the vehicle does not have a rear
seat that will accommodate a
rear-facing child restraint, a
rear-facing child restraint should not
be installed in the vehicle, even if
the airbag is off.
If the child restraint uses a top
tether, see Lower Anchors and
Tethers for Children (LATCH
System) 092 for top tether anchor
locations.
Do not secure a child seat in a
position without a top tether anchor
if a national or local law requires
that the top tether be anchored, or if

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
110 Seats and Restraints
the instructions that come with the
child restraint say that the top tether
must be anchored.
In Canada, the law requires that
forward-facing child restraints have
a top tether, and that the tether be
attached.
When using the lap-shoulder belt to
secure the child restraint in this
position, follow the instructions that
came with the child restraint and the
following instructions:1. Move the seat as far back as it will go before securing the
forward-facing child restraint.
Move the seat upward or the
seatback to an upright position,
if needed, to get a tight
installation of the child
restraint.
When the passenger sensing
system has turned off the front
outboard passenger frontal
airbag, the OFF indicator on
the passenger airbag status
indicator should light and stay lit when you start the vehicle.
See
Passenger Airbag Status
Indicator 0137.
2. Put the child restraint on the seat.
3. Pick up the latch plate, and run the lap and shoulder portions
of the vehicle seat belt through
or around the child restraint.
The child restraint instructions
will show you how.
Tilt the latch plate to adjust the
belt if needed.
4. Push the latch plate into thebuckle until it clicks.
Position the release button on
the buckle, away from the child
restraint, so that the seat belt
could be quickly unbuckled if
necessary.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Seats and Restraints 111
5. Pull the shoulder belt all theway out of the retractor to set
the lock. When the retractor
lock is set, the belt can be
tightened but not pulled out of
the retractor.6. To tighten the belt, push downon the child restraint, pull the
shoulder portion of the belt to
tighten the lap portion of the
belt, and feed the shoulder belt
back into the retractor. When
installing a forward-facing child
restraint, it may be helpful to
use your knee to push down on
the child restraint as you
tighten the belt.
Try to pull the belt out of the
retractor to make sure the
retractor is locked. If the
retractor is not locked, repeat
Steps 5 and 6. 7. If the vehicle does not have a
rear seat and the child restraint
manufacturer recommends
using a top tether anchor,
attach the top tether to the top
tether anchor. Refer to the
instructions that came with the
child restraint and to Lower
Anchors and Tethers for
Children (LATCH System) 092.
8. Before placing a child in the child restraint, make sure it is
securely held in place. To
check, grasp the child restraint
at the seat belt path and
attempt to move it side to side
and back and forth. When the
child restraint is properly
installed, there should be no
more than 2.5 cm (1 in) of
movement.
If the airbag is off, the OFF indicator
in the passenger airbag status
indicator will come on and stay on
when the vehicle is started.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
118 Instruments and Controls
Instruments and
Controls
Controls
Steering Wheel Adjustment . . . 119
Steering Wheel Controls . . . . . . 120
Heated Steering Wheel . . . . . . . 120
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Windshield Wiper/Washer . . . . 120
Compass . . . . . . . . . . . . . . . . . . . . . 121
Clock . . . . . . . . . . . . . . . . . . . . . . . . . 121
Power Outlets . . . . . . . . . . . . . . . . 122
Wireless Charging . . . . . . . . . . . . 124
Warning Lights, Gauges, and
Indicators
Warning Lights, Gauges, andIndicators . . . . . . . . . . . . . . . . . . . 126
Instrument Cluster . . . . . . . . . . . . 127
Speedometer . . . . . . . . . . . . . . . . . 131
Odometer . . . . . . . . . . . . . . . . . . . . . 132
Trip Odometer . . . . . . . . . . . . . . . . 132
Tachometer . . . . . . . . . . . . . . . . . . . 132
Fuel Gauge . . . . . . . . . . . . . . . . . . . 132
Engine Oil Pressure Gauge . . . . . . . . . . . . . . . . . . . . . . 133
Engine Coolant Temperature Gauge . . . . . . . . . . . . . . . . . . . . . . 134 Voltmeter Gauge . . . . . . . . . . . . . 135
Seat Belt Reminders . . . . . . . . . 136
Airbag Readiness Light . . . . . . . 136
Passenger Airbag Status
Indicator . . . . . . . . . . . . . . . . . . . . 137
Charging System Light . . . . . . . 138
Malfunction Indicator Lamp (Check Engine Light) . . . . . . . . 138
Brake System Warning Light . . . . . . . . . . . . . . . . . . . . . . . . 140
Electric Parking Brake Light . . . . . . . . . . . . . . . . . . . . . . . . 141
Service Electric Parking Brake Light . . . . . . . . . . . . . . . . . . . . . . . . 141
Antilock Brake System (ABS) Warning Light . . . . . . . . . . . . . . . 141
Four-Wheel-Drive Light . . . . . . . 142
Tow/Haul Mode Light . . . . . . . . . 142
Hill Descent Control Light . . . . 142
Lane Departure Warning (LDW) Light (2500/3500
Series) . . . . . . . . . . . . . . . . . . . . . . 142
Lane Keep Assist (LKA) Light (1500 Series) . . . . . . . . . . . . . . . 143
Vehicle Ahead Indicator . . . . . . 143
Pedestrian Ahead Indicator . . . 143
Traction Off Light . . . . . . . . . . . . . 143
Traction Control System (TCS)/ Electronic Stability Control
Light . . . . . . . . . . . . . . . . . . . . . . . . 144 Electronic Stability Control
(ESC) Off Light . . . . . . . . . . . . . . 144
Engine Coolant Temperature Warning Light . . . . . . . . . . . . . . . 145
Driver Mode Control Light . . . . 145
Tire Pressure Light . . . . . . . . . . . 145
Engine Oil Pressure Light
(Uplevel Cluster) . . . . . . . . . . . . 146
Low Fuel Warning Light . . . . . . 146
Security Light . . . . . . . . . . . . . . . . . 147
High-Beam On Light . . . . . . . . . . 147
Front Fog Lamp Light . . . . . . . . . 147
Lamps On Reminder . . . . . . . . . 147
Cruise Control Light . . . . . . . . . . 147
Door Ajar Light . . . . . . . . . . . . . . . 148
Information Displays
Driver Information Center (DIC) (Base Level) . . . . . . . . . . . . . . . . 148
Driver Information Center (DIC) (Midlevel and Uplevel) . . . . . . 149
Head-Up Display (HUD) . . . . . . 152
Vehicle Messages
Vehicle Messages . . . . . . . . . . . . 156
Engine Power Messages . . . . . 156
Vehicle Speed Messages . . . . . 156
Vehicle Personalization
Vehicle Personalization . . . . . . . 157

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 147
Security Light
The security light should come on
briefly as the engine is started. If it
does not come on, have the vehicle
serviced by your dealer. If the
system is working normally, the
indicator light turns off.
If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent
system. SeeImmobilizer Operation
0 39.
High-Beam On Light
This light comes on when the
high-beam headlamps are in use.
See Headlamp High/Low-Beam
Changer 0167.
IntelliBeam Light
This light comes on when the
IntelliBeam system, if equipped, is
enabled. See Exterior Lamp
Controls 0165.
Front Fog Lamp Light
For vehicles with fog lamps, this
light comes on when the fog lamps
are on. The light goes out when the fog
lamps are turned off. See
Fog
Lamps 0170.
Lamps On Reminder
This light comes on when the
exterior lamps are in use, except
when only the Daytime Running
Lamps (DRL) are active. See
Exterior Lamp Controls 0165.
Cruise Control Light