light GMC SIERRA 2021 Owner's Guide

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 103
Caution
Hanging heavy equipment from the
power outlet can cause damage not
covered by the vehicle warranty. The
power outlets are designed for accessory
power plugs only, such as cell phone
charge cords.
Power Outlet 110/120-Volt Alternating
Current
If equipped, the vehicle has two alternating
current power outlets.
In Cab Power Outlet and DC/AC Switch
Truck Bed Power Outlet
When the ignition is on, power is supplied
to the outlets after the DC/AC switch is
pressed. A green indicator light on the
DC/AC switch indicates when the DC/AC
operation is active. One power outlet can be
used with electrical equipment that uses a
maximum of 400 watts. If both outlets are
being used, 400 watts will be shared
between the outlets. Ensure that all
connected devices do not exceed 400 watts.
The power outlet can be turned off by
pressing the DC/AC switch. The power outlet
can be turned back on after 10 seconds,
during which the indicator light on the
switch will flash. An indicator light on the outlet illuminates
when power is provided to the outlet and
no system fault is detected. The outlets will
not operate when the ignition is off, the
DC/AC switch is not pressed, or the plug is
not fully seated into the outlet.
If equipment is connected using more than
400 watts or a system fault is detected, a
protection circuit shuts off the power supply
and the indicator light turns off.
Do not use a power outlet with a missing or
damaged cover.
The power outlet is not designed for the
following, and may not work properly if
they are plugged in:
.Equipment with high initial peak wattage,
such as compressor-driven refrigerators
and electric power tools
.Other equipment requiring an extremely
stable power supply, such as
microcomputer-controlled electric blankets
and touch sensor lamps
.Medical equipment
Wireless Charging
The vehicle may have wireless charging on
the center console in front of the
cupholders. The system operates at 145 kHz

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
106 Instruments and Controls
Warning Lights, Gauges, and
Indicators
Warning lights and gauges can signal that
something is wrong before it becomes
serious enough to cause an expensive repair
or replacement. Paying attention to the
warning lights and gauges could prevent
injury.
Some warning lights come on briefly when
the engine is started to indicate they are
working. When one of the warning lights
comes on and stays on while driving,
or when one of the gauges shows there
may be a problem, check the section that
explains what to do. Waiting to do repairs
can be costly and even dangerous.
Instrument Cluster
Base Cluster English Shown, Metric Similar
1.Tachometer 0110
2. Engine Oil Pressure Gauge 0111
3. Engine Coolant Temperature Gauge
0112
4. Fuel Gauge 0110
5. Voltmeter Gauge 0113 6.
Speedometer 0110
7. Driver Information Center (DIC) (Base
Level) 0124 or
Driver Information Center (DIC)
(Midlevel and Uplevel) 0125

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 109
.Home
.Info App. This is where the selected Driver
Information Center (DIC) displays can be
viewed. See“Driver Information Center
(DIC) (Uplevel)” in the Index.
.Audio
.Navigation
.Phone
.Options
Home
Information displayed here can be
customized from the Options menu.
Speedometer : Displays how fast the vehicle
is moving in either kilometers per hour
(km/h) or miles per hour (mph).
Speed Sign : Shows sign information, which
comes from a roadway database in the
onboard navigation, if equipped.
Time : Displays the current time.
Fuel Range : Displays the approximate
distance the vehicle can be driven without
refueling. The fuel range estimate is based
on an average of the vehicle’s fuel economy
over recent driving history and the amount
of fuel remaining in the fuel tank. Fuel
range cannot be reset. Audio
In the Audio menu, use the thumbwheel to
scroll through options, browse for music,
select from favorites, or change the audio
source. In the main view, scroll to change
the station or go to the next or previous
track.
Navigation
In the Navigation menu, if there is no active
route, a compass will be displayed. If there
is an active route, press the thumbwheel to
cancel or resume route guidance, mute or
unmute voice guidance, or access Recents or
Favorites.
Phone
In the Phone menu, if there is no active
phone call, view recent calls, scroll through
contacts, select from the favorites, or change
the phone source. If there is an active call,
mute the phone or switch to handset
operation.
Options
Use the thumbwheel to scroll through items
in the Options menu.
Head-up Display (HUD) :
If equipped, this
feature allows for adjusting the angle of the
HUD image and changing or turning off the
Speed Limit Sign.
HUD Rotation: Press the thumbwheel while
Adjust Rotation is highlighted to enter
Adjust Mode. Scroll to adjust the angle of
the HUD display. Press the thumbwheel to
confirm and save the setting. This feature
may only be available in P (Park).
Speed Limit Style: Press the thumbwheel
while Speed Limit Style is highlighted to
change the speed sign style or to turn it off.
Units : Press the thumbwheel while Units is
displayed to enter the Units menu. Choose
US or metric units by pressing the
thumbwheel while the desired item is
highlighted. A selected mark will be
displayed next to the selected item.
Info Page Options : Press the thumbwheel
while Info Page Options is displayed to
enter and select the items to be displayed
in the Info app. A selected mark will be
displayed next to the selected item.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
110 Instruments and Controls
Home :Press the thumbwheel to select the
available elements to display. Not all
elements will be available on all vehicles:
Speedometer, Speed Sign, Time, and Fuel
Range.
Display (Uplevel) : Press the thumbwheel to
enter the Display menu. Select to turn on or
off the compass or speed sign.
Speed Warning : The Speed Warning display
allows the driver to set a speed that they
do not want to exceed. To set the Speed
Warning, press the thumbwheel when Speed
Warning is displayed, or press the
thumbwheel on the main view to set the
speed value. Scroll to adjust the value. Press
the thumbwheel to set the speed. Once the
speed is set, this feature can be turned off
by pressing the thumbwheel while viewing
this page. If the selected speed limit is
exceeded, a pop-up warning is displayed
with a chime.
Software Information : Press the
thumbwheel while Software Information is
highlighted to display open source software
information.Speedometer
The speedometer shows the vehicle's speed
in either kilometers per hour (km/h) or
miles per hour (mph).
Odometer
The odometer shows how far the vehicle has
been driven, in either kilometers or miles.
Trip Odometer
The trip odometer shows how far the
vehicle has been driven since the trip
odometer was last reset.
The trip odometer is accessed and reset
through the Driver Information Center (DIC).
See Driver Information Center (DIC) (Base
Level) 0124 or
Driver Information Center (DIC) (Midlevel and
Uplevel) 0125.
Tachometer
The tachometer displays the engine speed in
revolutions per minute (rpm).
For vehicles with the Stop/Start system,
when the ignition is on, the tachometer
indicates the vehicle status. When pointing
to AUTO STOP, the engine is off but the vehicle is on and can move. The engine
could auto start at any time. When the
indicator points to OFF, the vehicle is off.
When the engine is on, the tachometer will
indicate the engine’s revolutions per minute
(rpm). The tachometer may vary by several
hundred rpm, during Auto Stop mode, when
the engine is shutting off and restarting.
Fuel Gauge
Metric Uplevel Shown, Midlevel and Base
Level Similar

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 111
English Uplevel Shown, Midlevel and BaseLevel Similar
When the ignition is on, the fuel gauge
indicates about how much fuel is left in
the tank.
There is an arrow near the fuel gauge
pointing to the side of the vehicle the fuel
door is on.
When the indicator nears empty, the low
fuel light comes on. There still is a little fuel
left, but the vehicle should be refueled soon.
Here are three things that some owners ask
about. None of these show a problem with
the fuel gauge:
.It takes a little more, or less fuel to fill up
than the gauge indicated. For example,
the gauge may have indicated the tank
was half full, but it actually took a little
more, or less than half the tank's capacity
to fill the tank.
.The gauge moves a little while turning a
corner, speeding up or braking.
.The gauge takes a few seconds to
stabilize after the ignition is turned on
and goes back to empty when the
ignition is turned off.
Engine Oil Pressure Gauge
Uplevel Metric Shown, Base Level and Midlevel Similar
Uplevel English Shown, Base Level and
Midlevel Similar
The engine oil pressure gauge shows the
engine oil pressure in kPa (kilopascals)
or psi (pounds per square inch) when the
engine is running.
Oil pressure can vary with engine speed,
outside temperature, coolant temperature,
and oil viscosity.
On some models, the oil pump will vary
engine oil pressure according to engine
needs. Oil pressure may change quickly as
the engine speed or load varies. This is
normal. If the oil pressure warning light or
Driver Information Center (DIC) message

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 113
Voltmeter Gauge
Uplevel Shown, Base Level and MidlevelSimilar
When the ignition is on, this gauge indicates
the battery voltage.
When the engine is running, this gauge
shows the condition of the charging system.
The gauge can transition from a higher to
lower or a lower to higher reading. This is
normal. If the vehicle is operating outside
the normal operating range, the charging
system light comes on. See Charging System
Light 0115. The voltmeter gauge may also
read lower when in fuel economy mode.
This is normal. Readings outside the normal operating
range can also occur when a large number
of electrical accessories are operating in the
vehicle and the engine is left idling for an
extended period. This condition is normal
since the charging system is not able to
provide full power at engine idle. As engine
speeds are increased, this condition should
correct itself as higher engine speeds allow
the charging system to create maximum
power.
The vehicle can only be driven for a short
time with the readings outside the normal
operating range. If the vehicle must be
driven, turn off all accessories, such as the
radio and air conditioner.
Readings outside the normal operating
range indicate a possible problem in the
electrical system. Have the vehicle serviced
as soon as possible.
Seat Belt Reminders
Driver Seat Belt Reminder Light
There is a driver seat belt reminder light on
the instrument cluster.
When the vehicle is started, this light
flashes and a chime may come on to remind
the driver to fasten their seat belt.
Then the light stays on solid until the belt is
buckled. This cycle may continue several
times if the driver remains or becomes
unbuckled while the vehicle is moving.
If the driver seat belt is buckled, neither the
light nor the chime comes on.
Front Passenger Seat Belt Reminder
Light
The vehicle may have a front passenger seat
belt reminder light near the passenger
airbag status indicator. See
Passenger
Sensing System 066.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
114 Instruments and Controls
When the vehicle is started, this light
flashes and a chime may come on to remind
passengers to fasten their seat belt.
Then the light stays on solid until the belt is
buckled. This cycle continues several times if
the front passenger remains or becomes
unbuckled while the vehicle is moving.
If the front passenger seat belt is buckled,
neither the chime nor the light comes on.
The front passenger seat belt reminder light
and chime may come on if an object is put
on the seat such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device. To turn off the reminder light and/or
chime, remove the object from the seat or
buckle the seat belt.
Airbag Readiness Light
This light shows if there is an electrical
problem with the airbag system. The system
check includes the airbag sensor(s), the
passenger sensing system, the pretensioners,
the airbag modules, the wiring, and the
crash sensing and diagnostic module. For
more information on the airbag system, see
Airbag System061.
The airbag readiness light comes on for
several seconds when the vehicle is started.
If the light does not come on then, have it
fixed immediately.
{Warning
If the airbag readiness light stays on
after the vehicle is started or comes on
while driving, it means the airbag system
might not be working properly. The
airbags in the vehicle might not inflate in
a crash, or they could even inflate
without a crash. To help avoid injury,
have the vehicle serviced right away.
If there is a problem with the airbag
system, a Driver Information Center (DIC)
message may also come on.
Passenger Airbag Status Indicator
The vehicle has a passenger sensing system.
See Passenger Sensing System 066 for
important safety information. The overhead
console has a passenger airbag status
indicator.
United States
Canada
When the vehicle is started, the passenger
airbag status indicator will light ON and OFF,
or the symbols for on and off, for several
seconds as a system check. Then, after
several more seconds, the status indicator

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 115
will light either ON or OFF, or either the on
or off symbol, to let you know the status of
the front outboard passenger frontal airbag.
If the word ON or the on symbol is lit on
the passenger airbag status indicator, it
means that the front outboard passenger
frontal airbag is allowed to inflate.
If the word OFF or the off symbol is lit on
the passenger airbag status indicator, it
means that the passenger sensing system
has turned off the front outboard passenger
frontal airbag.
If, after several seconds, both status
indicator lights remain on, or if there are no
lights at all, there may be a problem with
the lights or the passenger sensing system.
See your dealer for service.
{Warning
If the airbag readiness light ever comes
on and stays on, it means that
something may be wrong with the airbag
system. To help avoid injury to yourself
or others, have the vehicle serviced right
away. SeeAirbag Readiness Light 0114
for more information, including important
safety information.
Charging System Light
The charging system light comes on briefly
when the ignition is turned on, but the
engine is not running, as a check to show
the light is working. It should go out when
the engine is started.
If the light stays on, or comes on while
driving, there may be a problem with the
electrical charging system. Have it checked
by your dealer. Driving while this light is on
could drain the battery.
When this light comes on, or is flashing, the
Driver Information Center (DIC) also displays
a message.
If a short distance must be driven with the
light on, be sure to turn off all accessories,
such as the radio and air conditioner. Find a
safe place to stop the vehicle.
Malfunction Indicator Lamp
(Check Engine Light)
This light is part of the vehicle’s emission
control on-board diagnostic system. If this
light is on while the engine is running, a
malfunction has been detected and the
vehicle may require service. The light should
come on to show that it is working when
the ignition is on and the engine is not
running. See Ignition Positions (Keyless
Access) 0230 or
Ignition Positions (Key Access) 0229.
Malfunctions are often indicated by the
system before any problem is noticeable.
Being aware of the light and seeking service
promptly when it comes on may prevent
damage.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
116 Instruments and Controls
Caution
If the vehicle is driven continually with
this light on, the emission control system
may not work as well, the fuel economy
may be lower, and the vehicle may not
run smoothly. This could lead to costly
repairs that might not be covered by the
vehicle warranty.
Caution
Modifications to the engine, transmission,
exhaust, intake, or fuel system, or the
use of replacement tires that do not
meet the original tire specifications, can
cause this light to come on. This could
lead to costly repairs not covered by the
vehicle warranty. This could also affect
the vehicle’s ability to pass an Emissions
Inspection/Maintenance test. See
Accessories and Modifications0323.
If the light is flashing : A malfunction has
been detected that could damage the
emission control system and increase vehicle
emissions. Diagnosis and service may be
required. To help prevent damage, reduce vehicle
speed and avoid hard accelerations and
uphill grades. If towing a trailer, reduce the
amount of cargo being hauled as soon as
possible.
If the light continues to flash, find a safe
place to park. Turn the vehicle off and wait
at least 10 seconds before restarting the
engine. If the light is still flashing, follow
the previous guidelines and see your dealer
for service as soon as possible.
If the light is on steady :
A malfunction has
been detected. Diagnosis and service may be
required.
Check the following:
.If fuel has been added to the vehicle
using the capless funnel adapter, make
sure that it has been removed. See
“Filling the Tank with a Portable
Gas Can” underFilling the Tank (Pickup
Model) 0285 or
Filling the Tank (Chassis Cab Model) 0287. The diagnostic system can
detect if the adapter has been left
installed in the vehicle, allowing fuel to
evaporate into the atmosphere. A few
driving trips with the adapter removed
may turn off the light.
.Poor fuel quality can cause inefficient
engine operation and poor driveability,
which may go away once the engine is
warmed up. If this occurs, change the fuel
brand. It may require at least one full
tank of the proper fuel to turn the light
off. See Recommended Fuel (Except 6.2L
V8 Engine) 0283 or
Recommended Fuel (6.2L V8 Engine)
0 284.
If the light remains on, see your dealer.
Emissions Inspection and Maintenance
Programs
If the vehicle requires an Emissions
Inspection/Maintenance test, the test
equipment will likely connect to the
vehicle's Data Link Connector (DLC).
The DLC is under the instrument panel to
the left of the steering wheel. Connecting
devices that are not used to perform an
Emissions Inspection/Maintenance test or to

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 117
service the vehicle may affect vehicle
operation. SeeAdd-On Electrical Equipment
0 318. See your dealer if assistance is
needed.
The vehicle may not pass inspection if:
.The light is on when the engine is
running.
.The light does not come on when the
ignition is on while the engine is off.
.Critical emission control systems have not
been completely diagnosed. If this
happens, the vehicle would not be ready
for inspection and might require
several days of routine driving before the
system is ready for inspection. This can
happen if the 12-volt battery has recently
been replaced or run down, or if the
vehicle has been recently serviced.
See your dealer if the vehicle will not pass
or cannot be made ready for the test.
Brake System Warning Light
MetricEnglish
This light should come on briefly when the
vehicle is turned on. If it does not come on
then, have it fixed so it will be ready to
warn you if there is a problem.
If the light comes on and stays on at start
up, there is a brake problem. Have the brake
system inspected right away.
If the light comes on while driving, pull off
the road and stop carefully. If equipped with
electric brake boost, vehicle speed may be
limited when the brake system warning
light comes on. The brake pedal might be
harder to push, or the brake pedal may go
closer to the floor. It could take longer to
stop. If the light is still on, have the vehicle
towed for service. See Towing the Vehicle
0 394.
{Warning
The brake system might not be working
properly if the brake system warning
light is on. Driving with the brake system
warning light on can lead to a crash.
If the light is still on after the vehicle has
been pulled off the road and carefully
stopped, have the vehicle towed for
service.
Electric Parking Brake Light
MetricEnglish
This light comes on when the parking brake
is applied. If the light continues flashing
after the parking brake is released, or while
driving, there is a problem with the Electric
Parking Brake system. A message may also
display in the Driver Information
Center (DIC).
If the light does not come on, or remains
flashing, see your dealer.