
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 237
With the vehicle moving less than
5 km/h (3 mph) and the transmission in
N (Neutral), attempt the shift again.
Shifting Out of 4
n
1. The vehicle must be stopped or movingless than 5 km/h (3 mph) with the
transmission in N (Neutral) and the
ignition on. It is best for the vehicle to
be moving 1.6 to 3.2 km/h (1 to 2 mph).
2. Press 4
m, AUTO, or 2m. The actual 4x4
shift request is only made after the
button is released. The 4x4 graphic will
remain flashing until the shift request
has completed. A DIC message displays
to indicate the state of the request.
Once the 4x4 shift has completed, the
DIC message disappears, the 4x4 graphic
stops flashing, and the current setting is
indicated.
If vehicle speed is higher when shift
request occurs, a DIC message displays.
Reduce vehicle speed.
If the transmission is not in N (Neutral)
when shift request occurs, DIC messages will
display. The vehicle will allow 20 seconds for
this shift to occur. After this time, a graphic
in the instrument cluster will indicate that
the transfer case is in 4
n.
Caution
Shifting the transmission into gear before
the requested mode indicator light has
stopped flashing could damage the
transfer case.
If the transmission is not shifted into
N (Neutral) or the vehicle has not slowed to
5 km/h (3 mph) within 20 seconds, the
transfer case will remain in its original state.
This will be indicated in the instrument
cluster.
With the vehicle moving less than 5 km/h
(3 mph), and the transmission in N (Neutral),
attempt the shift again.
Shifting Into N (Neutral)
To shift into N (Neutral): 1. Start the vehicle.
2. Shift the transmission to N (Neutral).
3. Shift the transfer case to 2
m.
4. Apply the parking brake and/or brake pedal.
5. Press 2
mfive times in 10 seconds until
the N (Neutral) graphic starts flashing in
the instrument cluster. When the shift is
complete, the graphic stops flashing. If the parking brake and/or brake pedal
is not applied within 20 seconds, the
transfer case will remain in the original
state.
6. If the transmission is not shifted into N (Neutral) or the vehicle has not slowed
to 5 km/h (3 mph) within 20 seconds,
the transfer case will remain in its
original state. This will be indicated in
the instrument cluster.
Shifting Out of N (Neutral)
To shift out of N (Neutral): 1. Turn the ignition on with the engine off. See Ignition Positions (Key Access) 0221
or
Ignition Positions (Keyless Access) 0223.
2. Set the parking brake. See Electric
Parking Brake 0239.
3. Shift the transmission to N (Neutral).
4. Shift the transfer case to 2
m. Transfer
case shifts out of N (Neutral) can only be
made into 2
m. When the shift to 2mis
complete, the graphic in the instrument
cluster will stop flashing. If the transfer
case cannot complete a shift, the graphic
will return to the previously selected
setting.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/18/22
Vehicle Care 373
5. With the engine running, release theparking brake and verify that the
transfer case is in N (Neutral) by shifting
the transmission to D (Drive) and then to
R (Reverse). There should be no
movement while shifting the
transmission.
6. Shift the transmission to D (Drive).
7. If equipped with an ignition key, turn the ignition to ACC/ACCESSORY.
If equipped with Keyless Access, turn the
engine off. Disregard the Shift to P (Park)
DIC message. See Ignition Positions (Key
Access) 0221 or
Ignition Positions (Keyless Access) 0223.
{Warning
To avoid death, serious injury,
or property damage, before dinghy
towing the vehicle, always disconnect and
secure the negative battery cable and
cover the negative battery post and cable
with a non-conductive material. If the
battery is left connected or the battery
cable contacts the post, the Electric
Parking Brake may activate during
towing, which could cause a crash. 8. Disconnect the negative (–) battery
cable. See “Negative Battery Cable
Disconnection” inBattery - North
America 0319.
9. Shift the transmission to P (Park).
Caution
If the steering column is locked, vehicle
damage may occur.
10. Move the steering wheel to make sure the steering column is unlocked.
11. If the vehicle has an ignition key, keep it in the towed vehicle in ACC/ACCESSORY
to prevent the steering column from
locking. If the vehicle is equipped with
Keyless Access, keep the RKE transmitter
outside of the vehicle and manually lock
the doors. Access the vehicle by using
the key in the door lock. See Door Locks
0 23.
Disconnecting the Towed Vehicle
Before disconnecting from the tow vehicle: 1. Park on a level surface. Secure the vehicle with wheel blocks.
2. Re-connect the negative (–) battery. See Battery - North America 0319. 3. Turn on the ignition with the engine off.
For vehicles with a key, turn the ignition
to ON/RUN with the engine off. If the
vehicle is equipped with Keyless Access,
with your foot off the brake pedal, press
and hold ENGINE START/STOP for
five seconds until the green light comes
on in the button. See Ignition Positions
(Key Access) 0221 or
Ignition Positions (Keyless Access) 0223.
4. Set the parking brake. See Electric
Parking Brake 0239.
5. Disconnect from the tow vehicle.
6. Shift the transmission to N (Neutral).
7. Shift the transfer case to 2
m(Two-Wheel
Drive High). When the shift to 2
m
(Two-Wheel Drive High) is complete, the
light in the instrument cluster will stop
flashing and stay lit. See
Four-Wheel-Drive Light 0123.
8. Start the engine. Check that the vehicle is in 2
m(Two-Wheel Drive High) by
starting the engine and shifting the
transmission to D (Drive) and then to
R (Reverse). There should be movement
of the vehicle while shifting.
9. Shift the transmission to P (Park) and turn off the ignition.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Index 421
H
Halogen Bulbs . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Hazard Warning Flashers . . . . . . . . . . . . . . . . .142
HD Radio Technology . . . . . . . . . . . . . . . . . . . . 156
Head Restraints . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Head-Up Display (HUD) . . . . . . . . . . . . . . . . . . . 132
HeadlampsAiming . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 325
Automatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Bulb Replacement . . . . . . . . . . . . . . . . . . . . . . 325
Daytime Running Lamps (DRL) . . . . . . . . . . 141
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Headlamps, Front Turn Signal,Sidemarker, and Parking Lamps . . . . . . 325
High-Beam On Light . . . . . . . . . . . . . . . . . . . . 127
High/Low Beam Changer . . . . . . . . . . . . . . . 141
Lamps On Reminder . . . . . . . . . . . . . . . . . . . 128
Heated Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Rear Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Steering Wheel . . . . . . . . . . . . . . . . . . . . . . . . 105
Ventilated Front Seats . . . . . . . . . . . . . . . . . . 56
Heater Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226
Heating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196, 197
High-Beam On Light . . . . . . . . . . . . . . . . . . . . . . 127 Hill
Descent Control (HDC) . . . . . . . . . . . . . . . . . 242
Descent Control Light . . . . . . . . . . . . . . . . . . 123
Hill and Mountain Roads . . . . . . . . . . . . . . . . . 212
Hill Start Assist (HSA) . . . . . . . . . . . . . . . . . . . . 240
Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
Horn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106
How to Wear Seat Belts Properly . . . . . . . . . 59
HVAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .196, 197
I
If the System Needs Service . . . . . . . . . . . . . . 171
Ignition Positions . . . . . . . . . . . . . . . . . . . . 221, 223
Immobilizer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35
Indicator Vehicle Ahead . . . . . . . . . . . . . . . . . . . . . . . . . 124
Indicators
Warning Lights and Gauges . . . . . . . . . . . . . 111
Infants and Young Children, Restraints . . . . .77
Information Publication Ordering . . . . . . . . . . . . . . . . . . . 404
Infotainment Using the System . . . . . . . . . . . . . . . . . . . . . . 152
Infotainment System . . . . . . . . . . . . . . . . . . . . 407
Inspection Multi-Point Vehicle . . . . . . . . . . . . . . . . . . . . 387
Instrument Cluster . . . . . . . . . . . . . . . . . . . . . . . . 111
Instrument Panel Overview . . . . . . . . . . . . . . . . .5 Interior Rearview Mirrors . . . . . . . . . . . . . . . . . 40
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 2, 148
J
Jack
Auxiliary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
Jump
Starting - North America . . . . . . . . . . . . . . . 367
K
Keyless EntryRemote (RKE) System Operation . . . . . 12, 14
Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8, 11
L
Labeling, Tire Sidewall . . . . . . . . . . . . . . . . . . . 338
Lamps Auxiliary Roof Mounted Lamp . . . . . . . . . 144
Daytime Running (DRL) . . . . . . . . . . . . . . . . . 141
Dome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
Exterior Cargo . . . . . . . . . . . . . . . . . . . . . . . . . 144
Exterior Controls . . . . . . . . . . . . . . . . . . . . . . . 139
Exterior Lamps Off Reminder . . . . . . . . . . . 141
Exterior Lighting Battery Saver . . . . . . . . 147
Flash-to-Pass . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Fog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
High/Low Beam Changer . . . . . . . . . . . . . . . 141
License Plate . . . . . . . . . . . . . . . . . . . . . . . . . . . 327

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
424 Index
PhoneApple CarPlay and Android Auto . . . . . . . . 181
Bluetooth . . . . . . . . . . . . . . . . . . . . . . . . . . 176, 177
Pickup Conversion to Chassis Cab . . . . . . . . 300
Port USB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158
Positioning
Vehicle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170
Power Assist Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Door Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
Protection, Battery . . . . . . . . . . . . . . . . . . . . . 147
Retained Accessory (RAP) . . . . . . . . . . . . . . 227
Seat Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . 51
Steering Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Pregnancy, Using Seat Belts . . . . . . . . . . . . . . 64
Privacy Vehicle Data Recording . . . . . . . . . . . . . . . . 405
Problems with Route Guidance . . . . . . . . . . 170
Program Courtesy Transportation . . . . . . . . . . . . . . . 401
Prohibited Fuels . . . . . . . . . . . . . . . . . . . . . . . . . 264
Proposition 65 Warning
California . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Proposition 65 Warning, California . . . . . . . 367
Publication Ordering Information . . . . . . . . 404
R
Radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311
Radio
AM-FM Radio . . . . . . . . . . . . . . . . . . . . . . . . . . 154
Data System (RDS) . . . . . . . . . . . . . . . . . . . . . . 157
Frequency Statement . . . . . . . . . . . . . . . . . . 404
HD Radio Technology . . . . . . . . . . . . . . . . . . 156
Reception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Satellite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
Reading Lamps . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Rear Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
Camera Mirror . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Cross Traffic Alert (RCTA) System . . . . . . 257
Heated Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Locking Axle . . . . . . . . . . . . . . . . . . . . . . . . . . . 244
Seats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
Vision Camera (RVC) . . . . . . . . . . . . . . . . . . . 248
Windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Rearview Mirror Truck Bed Camera . . . . . . . . . . . . . . . . . . . . . . 43
Rearview Mirrors . . . . . . . . . . . . . . . . . . . . . . . . . .41
Automatic Dimming . . . . . . . . . . . . . . . . . . . . 41
Reclining Seatbacks . . . . . . . . . . . . . . . . . . . . . . . .52 Recognition
Voice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Recommended Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263
Recommended Fluids and Lubricants . . . . . 389
Records Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 391
Recreational Vehicle Towing . . . . . . . . . . . . . . 371
Reimbursement Program, GM Mobility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 399
Remote
Keyless Entry (RKE) System . . . . . . . . . . . . . . 12
Keyless Entry (RKE) SystemOperation . . . . . . . . . . . . . . . . . . . . . . . . . . 12, 14
Vehicle Start . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Replacement
Glass . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Replacement Parts Airbags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . 390
Replacing
Airbag System . . . . . . . . . . . . . . . . . . . . . . . . . . 75
LATCH System Parts After a Crash . . . . . . 92
Seat Belt System Parts after a Crash . . . . 65
Reporting Safety Defects
Canadian Government . . . . . . . . . . . . . . . . . 405
General Motors . . . . . . . . . . . . . . . . . . . . . . . . 405
U.S. Government . . . . . . . . . . . . . . . . . . . . . . . 404