2021 GMC SIERRA theft deterrent system

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 31
To extend the steps:
.Pressjto extend both steps. A DIC
message displays.
.Pressjagain to extend to the tire.
A DIC message displays.
.Pressjagain to return to normal
operation.
Enable/Disable
To enable or disable the power assist steps,
press and hold
jfor four seconds. A DIC
message displays.
Cleaning
Clean the power assist steps regularly. For
an automatic car wash, extend the steps
while in N (Neutral) using the center stack
switch. The steps will stow when shifting
into D (Drive).
Vehicle Security
This vehicle has theft-deterrent features;
however, they do not make the vehicle
impossible to steal.
Vehicle Alarm System
The indicator light, on the instrument panel
near the windshield, indicates the status of
the system.
Off : Alarm system is disarmed.
On Solid : Vehicle is secured during the
delay to arm the system.
Fast Flash : Vehicle is unsecured. A door or
the hood is open.
Slow Flash : Alarm system is armed.
Arming the Alarm System
1. Turn off the vehicle. 2. Lock the vehicle in one of two ways:
.Use the RKE transmitter.
.With a door open, pressQon the
interior of the door.
3. After 30 seconds, the alarm system will arm and the indicator light will begin to
slowly flash. Pressing
Qon the RKE
transmitter a second time will bypass
the 30-second delay and immediately
arm the alarm system.
The vehicle alarm system will not arm if the
doors are locked with the key.
If the driver door is opened without first
unlocking with the RKE transmitter, the horn
will chirp and the lights will flash to indicate
pre-alarm. If the vehicle is not started,
or the door is not unlocked by pressing
K
on the RKE transmitter during the 10-second
pre-alarm, the alarm will be activated.
The alarm will also be activated if a
passenger door or the hood is opened
without first disarming the system. When
the alarm is activated, the turn signals flash
and the horn sounds for about 30 seconds.
The alarm system will then re-arm to
monitor for the next unauthorized event.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
32 Keys, Doors, and Windows
Disarming the Alarm System
To disarm the alarm system or turn off the
alarm if it has been activated:
.PressKon the RKE transmitter.
.Start the vehicle.
To avoid setting off the alarm by mistake:
.Lock the vehicle after all occupants have
exited.
.Always unlock a door with the RKE
transmitter.
Unlocking the driver door with the key
will not disarm the system or turn off the
alarm.
How to Detect a Tamper Condition
IfKis pressed on the RKE transmitter and
the horn chirps three times, an alarm
occurred previously while the alarm system
was armed.
If the alarm has been activated, a message
will appear on the DIC.
Steering Column Lock
If equipped, the steering column lock is a
theft-deterrent device. This feature locks the
steering column when the vehicle is turned
off and the driver door is opened, or when the driver door is opened and then the
vehicle is turned off. The steering column
unlocks when the vehicle is turned on.
The Driver Information Center (DIC) may
display one of these messages:
.A message to service the steering column
lock indicates that an issue has been
detected with the column lock feature
and the vehicle should be serviced.
.A message that the steering column is
locked indicates that the engine is
running, but the steering column is still
locked. It is normal for the column to be
locked during a remote start, but the
column should unlock after the brake
pedal is pressed and the vehicle is started.
No message will display during a remote
start.
.A message that the steering wheel must
be turned and the vehicle must be started
again indicates that the column lock
mechanism is bound, the column locking
device was unable to unlock the steering
column, and the vehicle did not start.
If this happens, immediately turn the
steering wheel from side to side to
unbind the column lock. If this does not
unlock the steering column, turn the
vehicle off and open the driver door to
reset the system. Then turn the vehicle
on and immediately turn the steering
wheel side to side for about 15 seconds.
In some cases, it may take significant
force to unbind the column.
To keep the steering column from binding,
straighten the front wheels before turning
off the vehicle.
Immobilizer
See Radio Frequency Statement 0436.
Immobilizer Operation
This vehicle has a passive theft-deterrent
system.
The system does not have to be manually
armed or disarmed.
The vehicle is automatically immobilized
when the vehicle is turned off.
The system is automatically disarmed when
the ignition is turned from off to on.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Keys, Doors, and Windows 33
The security light, in the instrument cluster,
comes on if there is a problem with arming
or disarming the theft-deterrent system.
The system has one or more RKE
transmitters matched to an immobilizer
control unit in your vehicle. Only a correctly
matched RKE transmitter will start the
vehicle. If the transmitter is ever damaged,
you may not be able to start your vehicle.
When trying to start the vehicle, the
security light may come on briefly when the
ignition is turned on. If the engine does not
start and the security light stays on, there is
a problem with the system. Turn the
ignition off and try again.
If the vehicle will not change ignition modes
(ACC/ACCESSORY, on, off), and the RKE
transmitter appears to be undamaged, try
another transmitter. Or, you may try placing
the transmitter in the transmitter pocket
located in the center console. SeeRemote
Keyless Entry (RKE) System Operation (Key
Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013.
If the ignition mode will not change with
the other transmitter or with the
transmitter in the transmitter pocket, your
vehicle needs service. If the ignition does change modes, the first transmitter may be
faulty. See your dealer who can service the
theft-deterrent system and have a new RKE
transmitter programmed to the vehicle.
It is possible for the immobilizer system to
learn new or replacement RKE transmitters.
Up to eight transmitters can be
programmed for the vehicle. To program
additional transmitters, see "Programming
Transmitters to the Vehicle" under
Remote
Keyless Entry (RKE) System Operation (Key
Access) 010 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 013
Do not leave the transmitter or device that
disarms or deactivates the vehicle theft
system in the vehicle.
When equipped with a key, if the engine
still does not start, and the key appears to
be undamaged, try another ignition key.
It may be necessary to check the fuse. See
Fuses and Circuit Breakers 0353. If the
engine still does not start with the other
key, the vehicle needs service. If the vehicle
does start, the first key may be faulty. See
your dealer. It is possible for the
immobilizer system to learn new or
replacement keys. Up to eight keys can be
programmed for the vehicle. To program additional keys, see
Keys (Key Access)07or
Keys (Keyless Access) 09. Do not leave the
key or device that disarms or deactivates
the vehicle theft system in the vehicle.
See your dealer to get a new key blank cut
exactly as the ignition key that operates the
system.
Exterior Mirrors
Convex Mirrors
{Warning
A convex mirror can make things, like
other vehicles, look farther away than
they really are. If you cut too sharply
into the right lane, you could hit a
vehicle on the right. Check the inside
mirror or glance over your shoulder
before changing lanes.
Standard Mirrors
The passenger side mirror is convex shaped.
A convex mirror's surface is curved so more
can be seen from the driver seat.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./
Canada/Mexico-14632426) - 2021 - CRC - 11/5/20
Instruments and Controls 123
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 032.
High-Beam On Light
This light comes on when the high-beam
headlamps are in use. See Headlamp High/
Low-Beam Changer 0141.
IntelliBeam Light
This light comes on when the IntelliBeam
system, if equipped, is enabled. See Exterior
Lamp Controls 0139.
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 Lamps0143.
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 0139.
Cruise Control Light
The cruise control light is white when the
cruise control is on and ready, and turns
green when the cruise control is set and
active.
See Cruise Control 0254.
Adaptive Cruise Control Light
If equipped, this light is white when the
Adaptive Cruise Control (ACC) is on and
ready, and turns green when the ACC is set
and active. When ACC is engaged and the
driver accelerates, the indicator will turn
blue. See Adaptive Cruise Control (Camera)
0 256.

GMC Sierra/Sierra Denali 1500 Owner Manual (GMNA-Localizing-U.S./Cana-
da/Mexico-14632426) - 2021 - CRC - 11/5/20
458 Index
Storage Compartments . . . . . . . . . . . . . . . . . . . 95
StrutsGas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349
Stuck Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
Sun Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Sunroof . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Navigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
System Brake Pad Life . . . . . . . . . . . . . . . . . . . . . . . . . 342
Engine Air Filter Life . . . . . . . . . . . . . . . . . . . 333
Forward Collision Alert (FCA) . . . . . . . . . . . 275
Global Positioning . . . . . . . . . . . . . . . . . . . . . . 173
Infotainment . . . . . . . . . . . . . . . . . . . . . . . . . . . 439
OnStar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Systems
Driver Assistance . . . . . . . . . . . . . . . . . . . . . . 265
T
Tachometer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23
TaillampsBulb Replacement . . . . . . . . . . . . . . . . . . . . . . 351
Task Lighting . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
Teen Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 192
Text Telephone (TTY) Users . . . . . . . . . . . . . . 430
Theft-Deterrent Systems . . . . . . . . . . . . . . . . . . .32 Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
All-Season . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
All-Terrain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 362
Buying New Tires . . . . . . . . . . . . . . . . . . . . . . 376
Chains . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
Changing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381
Designations . . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Different Size . . . . . . . . . . . . . . . . . . . . . . . . . . 377
Full-Size Spare . . . . . . . . . . . . . . . . . . . . . . . . . 390
If a Tire Goes Flat . . . . . . . . . . . . . . . . . . . . . 380
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 373
Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 367
Pressure Light . . . . . . . . . . . . . . . . . . . . . . . . . 122
Pressure Monitor Operation . . . . . . . . . . . 369
Pressure Monitor System . . . . . . . . . . . . . . 368
Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 374
Sidewall Labeling . . . . . . . . . . . . . . . . . . . . . . 362
Terminology and Definitions . . . . . . . . . . . 365
Uniform Tire Quality Grading . . . . . . . . . . 377
Wheel Alignment and Tire Balance . . . . 378
Wheel Replacement . . . . . . . . . . . . . . . . . . . . 378
When It Is Time for New Tires . . . . . . . . . 375
Winter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 361
Top Tier Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . 283
Tow/Haul Mode . . . . . . . . . . . . . . . . . . . . . . . . . 242
Tow/Haul Mode Light . . . . . . . . . . . . . . . . . . . . 119 Towing
Driving Characteristics . . . . . . . . . . . . . . . . . 288
Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
General Information . . . . . . . . . . . . . . . . . . . 288
Recreational Vehicle . . . . . . . . . . . . . . . . . . . 395
Trailer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Trailer Sway Control (TSC) . . . . . . . . . . . . . 306
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 394
Traction Limited-Slip Differential . . . . . . . . . . . . . . . . 254
Off Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Traction Control/Electronic Stability Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 248
Trademarks and License Agreements . . . . . 195
Trailer Sway Control (TSC) . . . . . . . . . . . . . . . . . . . . 306
Tow Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Towing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 293
Trailer Towing App . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Trailering App . . . . . . . . . . . . . . . . . . . . . . . . . . . 307
Transfer Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242
Transmission
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Fluid, Automatic . . . . . . . . . . . . . . . . . . . . . . . 333
Transportation Program, Courtesy . . . . . . . 433
Trip Odometer . . . . . . . . . . . . . . . . . . . . . . . . . . . .110
Truck-Camper Loading Information . . . . . . . 226