2021 GMC SIERRA warning light

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
118 Instruments and Controls
Service Electric Parking Brake
Light
This light should come on briefly when
starting the vehicle. If it does not come on,
have it fixed so it will be ready to warn if
there is a problem.
If this light stays on, take the vehicle to
your dealer as soon as possible. See the
information for the Electric Parking Brake
underElectric Parking Brake 0247.
A message may also display in the Driver
Information Center (DIC).
Antilock Brake System (ABS)
Warning Light
This warning light should come on briefly
when the vehicle is turned on. If the light
does not come on, have it fixed so it will be
ready to warn if there is a problem.
If the light comes on while driving, safely
stop as soon as it is possible and turn off
the vehicle. Then turn on the vehicle again
to reset the system.
If the ABS warning light stays on, or comes
on again while driving, the vehicle needs
service. A chime may also sound when the
light stays on.
If the ABS warning light is the only light on,
the vehicle has regular brakes, but ABS is
not functioning. If both the ABS warning light and the brake
system warning light are on, ABS is not
functioning and there is a problem with the
regular brakes. See your dealer for service.
See
Brake System Warning Light 0117.
Four-Wheel-Drive Light
Auto Mode Shown, Other Modes Similar
If equipped, the four-wheel-drive light
displays what mode the vehicle is in. The
light will show each mode: 2WD, 4HI, AUTO
(all transfer cases); 4LOW and N (two-speed
transfer case only).
The light will flash when a shift is in
progress. Once the shift is complete the
light will be steady.
If the light turns amber, there may be a
malfunction with the four-wheel-drive
system. See your dealer.
See Four-Wheel Drive 0242.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 119
Tow/Haul Mode Light
For vehicles with the Tow/Haul Mode
feature, this light comes on when the Tow/
Haul Mode has been activated.
SeeTow/Haul Mode 0242.
Hill Descent Control Light
If equipped, the Hill Descent Control light
comes on when the system is ready for use.
When the light flashes, the system is active.
See Hill Descent Control (HDC) 0250.
Lane Keep Assist (LKA) Light
After the vehicle is started, this light turns
off and stays off if LKA has not been turned
on or is unavailable.
If equipped, this light is white if LKA is
turned on, but not ready to assist. This light
is green if LKA is turned on and is ready to
assist.
LKA may assist by gently turning the
steering wheel if the vehicle approaches a
detected lane marking. The LKA light is
amber when assisting.
This light flashes amber as a Lane Departure
Warning (LDW) alert, to indicate that the
lane marking has been crossed.
LKA will not assist or alert if the turn signal
is active in the direction of lane departure,
or if LKA detects that you are accelerating,
braking, or actively steering.
See Lane Keep Assist (LKA) 0281.
Vehicle Ahead Indicator
If equipped, this indicator will display green
when a vehicle is detected ahead and amber
when you are following a vehicle ahead
much too closely.
See Forward Collision Alert (FCA) System
0 275.
Pedestrian Ahead Indicator
If equipped, this indicator will display amber
when a nearby pedestrian is detected in
front of the vehicle.
See Front Pedestrian Braking (FPB) System
0 278.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 121
serviced by your dealer. If the system is
working normally, the indicator light then
turns off. This light comes on when the
Electronic Stability Control (ESC) system is
turned off. If ESC is off, the Traction Control
System (TCS) is also off. To turn ESC off and
on, seeTraction Control/Electronic Stability
Control 0248.
If ESC and TCS are off, the systems do not
assist in controlling the vehicle. Adjust
driving accordingly.
Engine Coolant Temperature
Warning Light
This light comes on briefly while starting
the vehicle.
If it does not, have the vehicle serviced by
your dealer. If the system is working
normally the indicator light goes off.
Caution
The engine coolant temperature warning
light indicates that the vehicle has
overheated. Driving with this light on can
damage the engine and it may not be
covered by the vehicle warranty. See
Engine Overheating 0338.
The engine coolant temperature warning
light comes on when the engine has
overheated.
If this happens, pull over and turn off the
engine as soon as possible. See Engine
Overheating 0338.
Driver Mode Control Light
This light comes on when Sport Mode is
selected.
This light comes on when Snow/Ice Mode is
selected.
This light comes on when Terrain Mode is
selected.
This light comes on when Off-Road Mode is
selected.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
122 Instruments and Controls
Tire Pressure Light
For vehicles with the Tire Pressure Monitor
System (TPMS), this light comes on briefly
when the engine is started. It provides
information about tire pressures and
the TPMS.
When the Light Is On Steady
This indicates that one or more of the tires
are significantly underinflated.
A Driver Information Center (DIC) tire
pressure message may also display. Stop as
soon as possible, and inflate the tires to the
pressure value shown on the Tire and
Loading Information label. SeeTire Pressure
0 367.
When the Light Flashes First and Then Is On
Steady
If the light flashes for about a minute and
then stays on, there may be a problem with
the TPMS. If the problem is not corrected, the light will come on at every ignition
cycle. See
Tire Pressure Monitor Operation
0 369.
Engine Oil Pressure Light (Uplevel
Cluster)
Caution
Lack of proper engine oil maintenance
can damage the engine. Driving with the
engine oil low can also damage the
engine. The repairs would not be covered
by the vehicle warranty. Check the oil
level as soon as possible. Add oil if
required, but if the oil level is within the
operating range and the oil pressure is
still low, have the vehicle serviced.
Always follow the maintenance schedule
for changing engine oil.
This 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 light comes on and stays on, it means
that oil is not flowing through the engine
properly. The vehicle could be low on oil
and might have some other system
problem. See your dealer.
Low Fuel Warning Light
This light is near the fuel gauge and comes
on briefly when the ignition is turned on as
a check to show it is working.
It also comes on when the fuel tank is low
on fuel. The light turns off when fuel is
added. If it does not, have the vehicle
serviced.
Security Light

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/6/20
Lighting 139
Lighting
Exterior Lighting
Exterior Lamp Controls . . . . . . . . . . . . . . . . 139
Exterior Lamps Off Reminder . . . . . . . . . . . 141
Headlamp High/Low-Beam Changer . . . . 141
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Daytime Running Lamps (DRL) . . . . . . . . . 141
Automatic Headlamp System . . . . . . . . . . 142
Hazard Warning Flashers . . . . . . . . . . . . . . 142
Turn and Lane-Change Signals . . . . . . . . . 143
Fog Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
Task Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . 144
Auxiliary Roof-Mounted Lamp . . . . . . . . . 144
Exterior Cargo Lamps . . . . . . . . . . . . . . . . . . 144
Interior Lighting
Instrument Panel IlluminationControl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Dome Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . 146
Lighting Features
Entry Lighting . . . . . . . . . . . . . . . . . . . . . . . . . 146
Exit Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Battery Load Management . . . . . . . . . . . . 146
Battery Power Protection . . . . . . . . . . . . . . 147
Exterior Lighting Battery Saver . . . . . . . . 147
Exterior Lighting
Exterior Lamp Controls
The exterior lamp control is on the
instrument panel to the left of the steering
wheel.
O: Turns off the automatic headlamps and
Daytime Running Lamps (DRL). Turn the
headlamp control to
Oagain to turn the
automatic headlamps or DRL back on.
For vehicles first sold in Canada, off will only
work when the vehicle is in P (Park). AUTO :
Automatically turns on the
headlamps, parking lamps, taillamps,
instrument panel lights, roof marker lamps
(if equipped), front/rear sidemarker lamps,
and license plate lamps.
;: Turns on the parking lamps including
all lamps, except the headlamps and fog
lamps, if equipped.
For some trim levels and series of trucks
first sold in Canada, the headlamps may
turn on with the parking lamps.
2: Turns on the headlamps together with
the parking lamps, taillamps, instrument
panel lights, roof marker lamps (if
equipped), front/rear sidemarker lamps, and
license plate lamps.
When the headlamps are turned on while
the vehicle is on, the headlamps turn off
automatically 10 minutes after the ignition
is turned off. When the headlamps are
turned on while the vehicle is off, the
headlamps will stay on for 10 minutes
before turning off to prevent the battery
from being drained. Turn the headlamp
control off and then back to the headlamp
on position to make the headlamps stay on

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/6/20
142 Lighting
Automatic Headlamp System
When the exterior lamp control is set to
AUTO and it is dark enough outside, the
headlamps come on automatically.
There is a light sensor on top of the
instrument panel. Do not cover the sensor,
otherwise the headlamps will come on when
they are not needed.
The system may also turn on the headlamps
when driving through a parking garage or
tunnel.
If the vehicle is started in a dark garage, the
automatic headlamp system comes on
immediately. If it is light outside when the
vehicle leaves the garage, there is a slightdelay before the automatic headlamp
system changes to the Daytime Running
Lamps (DRL). During that delay, the
instrument cluster may not be as bright as
usual. Make sure the instrument panel
illumination control is in the full bright
position. See
Instrument Panel Illumination
Control 0145.
When it is bright enough outside, the
headlamps will turn off or may change
to DRL.
The automatic headlamp system turns off
when the exterior lamp control is turned to
Oor the ignition is off.
Lights On with Wipers
If the windshield wipers are activated in
daylight with the engine on, and the
exterior lamp control is in AUTO, the
headlamps, parking lamps, and other
exterior lamps come on. The transition time
for the lamps coming on varies based on
wiper speed. When the wipers are not
operating, these lamps turn off. Move the
exterior lamp control to
Oor;to disable
this feature.
Hazard Warning Flashers
|: Press this button to make the front
and rear turn signal lamps flash on and off.
Press again to turn the flashers off.
When the hazard warning flashers are on,
the vehicle's turn signals will not work.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
194 Infotainment System
Manage Settings
Audio Volume Limit :Allows the audio
volume limit to be turned on or off. Touch
Set Audio Volume Limit to choose the
maximum allowable audio volume level.
Set Audio Volume Limit : Allows a
maximum radio volume to be set. Use the
arrows to choose the maximum allowable
level for the audio volume.
Teen Driver Speed Limiter : Limits the
maximum speed of the vehicle. When the
speed limiter is turned on and the vehicle is
started with a Teen Driver key, the DIC
displays a message that the top speed is
limited.
On certain vehicles, when the Speed Limiter
is turned ON, the vehicle’s maximum
acceleration will be limited. The DIC will
display a message that the acceleration is
limited.
Teen Driver Speed Warning : Allows the
speed warning to be turned on or off. Touch
Set Teen Driver Speed Warning to set the
warning speed. Set Teen Driver Speed Warning :
Displays a
warning in the DIC when exceeding a
selectable speed. Choose the desired speed
warning level. The speed warning does not
limit the speed of the vehicle.
SiriusXM Explicit Content Filter (if
equipped) : Allows the SiriusXM Explicit
Content Filter to be turned ON or OFF.
When ON, the teen driver will not be able
to listen to SiriusXM stations that contain
explicit content, and the Explicit Content
Filter selection in the Audio Settings will be
unavailable for change.
When Teen Driver is Active:
.If equipped with Buckle to Drive, shifting
out of P (Park) will be prevented if the
driver seat belt, and in some vehicles the
front passenger seat belt, is not buckled.
.The radio will mute when the driver seat
belt, and in some vehicles the front
passenger seat belt, is not buckled. The
audio from any device paired to the
vehicle will also be muted.
.An object placed on the front passenger
seat, such as a briefcase, handbag,
grocery bag, laptop, or other electronic
device, could cause the passenger sensing
system to falsely sense an unbuckled
front passenger and mute the radio. If this happens, remove the object from
the seat. See
Passenger Sensing System
0 66.
.Some safety systems, such as Forward
Collision Alert, if equipped, cannot be
turned off.
.The gap setting for the Forward Collision
Alert and Adaptive Cruise Control,
if equipped, cannot be changed.
.When trying to change a safety feature
that is not configurable in Teen Driver,
the DIC displays a message indicating
that Teen Driver is active and the action
is not available.
.Super Cruise, if equipped, is not available.
.Enhanced Low Fuel Warning (if equipped)
–When the vehicle is low on fuel, the
low fuel light on the instrument cluster
flashes and the DIC low fuel warning
cannot be dismissed.
.Do not tow a trailer.
Report Card
The vehicle owner must secure the driver’s
consent to record certain vehicle data when
the vehicle is driven with a registered Teen
Driver key. There is one Report Card per

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Driving and Operating 217
{Warning
If the vehicle has the two-speed
automatic transfer case, shifting the
transfer case to N (Neutral) can cause
your vehicle to roll even if the
transmission is in P (Park). This is because
the N (Neutral) position on the transfer
case overrides the transmission. You or
someone else could be injured. If leaving
the vehicle, set the parking brake and
shift the transmission to P (Park). Shift
the transfer case to any position but
N (Neutral).
.When driving down a hill, keep the
vehicle headed straight down. Use a low
gear because the engine will work with
the brakes to slow the vehicle and help
keep the vehicle under control.
{Warning
Heavy braking when going down a hill
can cause your brakes to overheat and
fade. This could cause loss of control and
you or others could be injured or killed.(Continued)
Warning (Continued)
Apply the brakes lightly when descending
a hill and use a low gear to keep vehicle
speed under control.
If a brake fade condition is detected, a DIC
warning message is displayed. Adjust brake
pedal use and shift to a lower transmission
gear to reduce braking.
If the brakes continue to fade to a severe
condition, additional DIC messages are
displayed. The brake system warning light
will illuminate, and the vehicle speed may
be limited. See Brake System Warning Light
0 117.
If the vehicle stalls on a hill: 1. Apply the brakes to stop the vehicle, and then apply the parking brake.
2. Shift into P (Park) and then restart the engine.
.If driving uphill when the vehicle
stalls, shift to R (Reverse), release the
parking brake, and back
straight down.
.Never try to turn the vehicle around.
If the hill is steep enough to stall the
vehicle, it is steep enough to cause it
to roll over.
.If you cannot make it up the hill,
back straight down the hill.
.Never back down a hill in N (Neutral)
using only the brake. The vehicle can
roll backward quickly and you could
lose control.
.If driving downhill when the vehicle
stalls, shift to a lower gear, release
the parking brake, and drive straight
down the hill.
3. If the vehicle cannot be restarted after stalling, set the parking brake, shift into
P (Park), and turn the vehicle off.
3.1. Leave the vehicle and seek help.
3.2. Stay clear of the path the vehicle would take if it rolled downhill.
.Avoid turns that take the vehicle across
the incline of the hill. A hill that can be
driven straight up or down might be too
steep to drive across. Driving across an
incline puts more weight on the downhill
wheels, which could cause a downhill
slide or a rollover.