2020 GMC SIERRA DENALI parking brake

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 421
6.6L V8 Engine (L8T) Only
1. Good Battery PositiveTerminal
2. Good Battery Negative Terminal
3. Discharged Battery Remote Positive Terminal
4. Discharged Battery Remote Negative Terminal
The jump start positive post (1) and
negative post (2) are on the battery
of the vehicle providing the jump
start. The jump start positive post (3) and
the negative grounding point (4) for
the discharged battery are on the
passenger side of the vehicle.
The positive jump start connection
for the discharged battery is under a
cover. Slide the cover to expose the
terminal.
1. Check the other vehicle. It must have a 12-volt battery
with a negative ground system.
Caution
If the other vehicle does not have
a 12-volt system with a negative
ground, both vehicles can be
damaged. Only use a vehicle that
has a 12-volt system with a
negative ground for jump starting.
2. If you have a vehicle with a diesel engine with two
batteries, you should know
before you begin that,
especially in cold weather, you
may not be able to get enough
power from a single battery in another vehicle to start your
diesel engine. If your vehicle
has more than one battery,
using the battery that is closer
to the starter will reduce
electrical resistance. This is
located on the passenger side,
in the rear of the engine
compartment.
3. Get the vehicles close enough so the jumper cables can
reach, but be sure the vehicles
are not touching each other.
If they are, it could cause an
unwanted ground connection.
You would not be able to start
your vehicle, and the bad
grounding could damage the
electrical systems.
To avoid the possibility of the
vehicles rolling, set the parking
brake firmly on both vehicles
involved in the jump start
procedure. Put the automatic
transmission in P (Park) before
setting the parking brake. If you
have a four-wheel-drive

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
426 Vehicle Care
Two-wheel-drive vehicles and
vehicles with a single-speed transfer
case should not be towed with all
four wheels on the ground.
Dinghy Towing (Vehicles with a
Two-Speed Transfer Case)
Only dinghy tow four-wheel-drive
vehicles with a two-speed transfer
case that have an N (Neutral) and a
4
n(Four-Wheel Drive Low) setting.
{Warning
Shifting a four-wheel-drive
vehicle's transfer case into
N (Neutral) can allow the vehicle
to move even if the transmission
is in P (Park). You or others could
be injured. Set the parking brake
and use wheel blocks before
shifting the transfer case to
N (Neutral).
To dinghy tow: 1. Position the vehicle being towed behind the tow vehicle,
facing forward and on a level
surface.
2. Securely attach the vehicle being towed to the tow vehicle.
3. Start the engine.
4. Shift the transfer case to N (Neutral). See “Shifting into
N (Neutral)” underFour-Wheel
Drive 0227. 5. With the engine running,
release the parking 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 (Keyless
Access) 0208 or
Ignition Positions (Key Access)
0 210.
{Warning
To avoid death, serious injury,
or property damage, before
dinghy towing the vehicle, always
disconnect and secure the
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Vehicle Care 427
Warning (Continued)
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”
in Battery - North America
0 358.
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 026.
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 0358. 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 (Keyless
Access) 0208 or
Ignition Positions (Key Access)
0 210.
4. Set the parking brake. See Electric Parking Brake 0233.
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
0 141.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
428 Vehicle Care
8. Start the engine. Check thatthe 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.
10. Release the parking brake and remove the wheel blocks.
11. Reset any lost presets. The outside temperature
display will default to 0 °C
(32 °F) but will reset with
normal usage.
Dolly TowingCaution
Do not tow this vehicle with two
wheels on the ground, or vehicle
damage could occur. This
damage would not be covered by
the vehicle warranty.
Dolly towing this vehicle is not
allowed with either the front or the
rear tires on the ground for
two-wheel drive or four-wheel drive,
regardless of transfer case.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 8/27/19
Service and Maintenance 443
.Lubricate body components. See
Exterior Care 0429.
. Check starter switch. See Starter
Switch Check 0363.
. Check automatic transmission
shift lock control function. See
Automatic Transmission Shift
Lock Control Function Check
0363.
. Check ignition transmission lock.
See Ignition Transmission Lock
Check 0363.
. Check parking brake and
automatic transmission park
mechanism. See Park Brake and
P (Park) Mechanism Check
0 364.
. Check accelerator pedal for
damage, high effort, or binding.
Replace if needed.
. Visually inspect gas strut for
signs of wear, cracks, or other
damage. Check the hold open
ability of the strut. If the hold
open is low, service the gas
strut. See Gas Strut(s) 0365. .
Inspect sunroof track and seal,
if equipped. See Sunroof050.
. Verify spare tire key lock
operation and lubricate as
needed. See Tire Changing
0 407.
. Visually inspect the spare tire to
ensure that it is tightly stowed
under the vehicle. Push, pull,
and try to turn the tire. If the
spare tire moves, tighten as
necessary. See Tire Changing
0 407.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
488 Index
Assistance Program,Roadside . . . . . . . . . . . . . . . . . . . . . . 466
Assistance Systems for Driving . . . . . . . . . . . . . . . . . . . . . . . . 268
Assistance Systems for Parking and Backing . . . . . . . . . . 257
Auto Stop
Stop/Start System . . . . . . . . . . . . 213
Automatic Dimming Mirrors . . . . . . . . . . . . . . . . 43
Door Locks . . . . . . . . . . . . . . . . . . . . . 27
Emergency Braking (AEB) . . . . 270
Headlamp System . . . . . . . . . . . . 168
Transmission . . . . . . . . . . . . . . . . . 221
Transmission Fluid . . . . . . . . . . . 343
Automatic Transmission
Manual Mode . . . . . . . . . . . . . . . . . 224
Shift Lock Control FunctionCheck . . . . . . . . . . . . . . . . . . . . . . . 363
Axle, Front . . . . . . . . . . . . . . . . . . . . . . 361
Axle, Rear . . . . . . . . . . . . . . . . . . . . . . 362
B
Battery Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . 174
Load Management . . . . . . . . . . . . 174 Battery (cont'd)
Power Protection . . . . . . . . . . . . . 174
Battery - North America . . . . 358, 419
Blade Replacement, Wiper . . . . . 364
Blind Spot Mirrors . . . . . . . . . . . . . . . 43
Brake Electric Boost . . . . . . . . . . . . . . . . . 232
Parking, Electric . . . . . . . . . . . . . . 233
System Warning Light . . . . . . . . 139
Brake Pad Life System . . . . . . . . . 356
Brakes . . . . . . . . . . . . . . . . . . . . . . . . . . 355 Antilock . . . . . . . . . . . . . . . . . . . . . . . 232
Assist . . . . . . . . . . . . . . . . . . . . . . . . . 234
Fluid . . . . . . . . . . . . . . . . . . . . . . . . . . 357
Pad Life System . . . . . . . . . . . . . . 356
Braking . . . . . . . . . . . . . . . . . . . . . . . . . 188 AutomaticEmergency (AEB) . . . . . . . . . . . 270
Braking System Front Pedestrian (FPB) . . . . . . . 272
Break-In, New Vehicle . . . . . . . . . . 208
Bulb Replacement Center High-Mounted
Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 369
Halogen Bulbs . . . . . . . . . . . . . . . . 367
Headlamp Aiming . . . . . . . . . . . . . 366
Headlamps . . . . . . . . . . . . . . . . . . . 367 Bulb Replacement (cont'd)
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . . . 367
License Plate Lamps . . . . . . . . . 369
Taillamps, Turn Signal, Stoplamps, and Back-up
Lamps . . . . . . . . . . . . . . . . . . . . . . 368
Buying New Tires . . . . . . . . . . . . . . . 399
C
Calibration . . . . . . . . . . . . . . . . . . . . . . 120
California Perchlorate Materials
Requirements . . . . . . . . . . . . . . . 329
California Proposition
65 Warning . . . . . . . . . .329, 358, 419, Back Cover
Canadian Vehicle Owners . . . . . . . . 2
Capacities and Specifications . . . . . . . . . . . . . . . . . 458
Carbon Monoxide Engine Exhaust . . . . . . . . . . . . . . . 220
Tailgate . . . . . . . . . . . . . . . . . . . . . . . . . 29
Winter Driving . . . . . . . . . . . . . . . . 197
Cargo Tie-Downs . . . . . . . . . . . . . . . . . . . . .115

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
490 Index
DiagnosticsConnected Services . . . . . . . . . . 486
Differential, Limited-Slip . . . . . . . . 242
Distracted Driving . . . . . . . . . . . . . . . 187
Dome Lamps . . . . . . . . . . . . . . . . . . . 172
Door Ajar Light . . . . . . . . . . . . . . . . . . . . . 147
Delayed Locking . . . . . . . . . . . . . . . . 27
Locks . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Power Locks . . . . . . . . . . . . . . . . . . . . 27
Drive Belt Routing, Engine . . . . . . 461
Driver Assistance Systems . . . . . 255
Driver Information
Center (DIC) . . . . . . . . . . . . . 147, 148
Driver Mode Control . . . . . . . . . . . . 238
Driver Mode Control Light . . . . . . 144
Driving Assistance Systems . . . . . . . . . . 268
Better Fuel Economy . . . . . . . . . 186
Characteristics andTowing Tips . . . . . . . . . . . . . . . . . 287
Defensive . . . . . . . . . . . . . . . . . . . . . 187
Drunk . . . . . . . . . . . . . . . . . . . . . . . . . 188
Hill and Mountain Roads . . . . . . 197
If the Vehicle is Stuck . . . . . . . . . 199
Loss of Control . . . . . . . . . . . . . . . 190
Off-Road . . . . . . . . . . . . . . . . . . . . . 191
Off-Road Recovery . . . . . . . . . . . 190 Driving (cont'd)
Vehicle Load Limits . . . . . . . . . . . 200
Wet Roads . . . . . . . . . . . . . . . . . . . 196
Winter . . . . . . . . . . . . . . . . . . . . . . . . 197
Dual Automatic Climate Control System . . . . . . . . . . . . . . . . 179
E
E85 or FlexFuel . . . . . . . . . . . . . . . . 282
Electric Brake Boost . . . . . . . . . . . . 232
Electric Parking Brake . . . . . . . . . . 233
Electric Parking Brake Light . . . . 140
Electrical Equipment,Add-On . . . . . . . . . . . . . . . . . . . . . . . 322
Electrical System Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . 371
Fuses and Circuit Breakers . . . 370
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . 374, 376
Overload . . . . . . . . . . . . . . . . . . . . . 370
Electronic Stability Control (ESC) Off Light . . . . . . . . . . . . . . . . 143
Emergency
OnStar . . . . . . . . . . . . . . . . . . . . . . . 477
Engine Air Cleaner/Filter . . . . . . . . . . . . . 344 Engine (cont'd)
Check Light (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . 137
Compartment Overview . . . . . . . 332
Coolant Temperature
Gauge . . . . . . . . . . . . . . . . . . . . . . 133
Coolant Temperature Warning Light . . . . . . . . . . . . . . . 144
Cooling System . . . . . . . . . . . . . . . 346
Drive Belt Routing . . . . . . . . . . . . 461
Exhaust . . . . . . . . . . . . . . . . . . . . . . 220
Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
Heater . . . . . . . . . . . . . . . . . . . . . . . . 215
Oil Life System . . . . . . . . . . . . . . . 341
Oil Pressure Gauge . . . . . . . . . . 132
Oil Pressure Light . . . . . . . . . . . . 145
Overheated Protection Operating Mode . . . . . . . . . . . . . 352
Overheating . . . . . . . . . . . . . . . . . . 351
Power Messages . . . . . . . . . . . . . 155
Running While Parked . . . . . . . . 220
Starting . . . . . . . . . . . . . . . . . . . . . . . 212
Engine Air Filter Life System . . . . 343
Entry Lighting . . . . . . . . . . . . . . . . . . . 173
Equipment, Towing . . . . . . . . . . . . . 296
Event Data Recorders . . . . . . . . . . 474
Exit Lighting . . . . . . . . . . . . . . . . . . . . 173
Extended Parking . . . . . . . . . . . . . . . 219

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 8/27/19
Index 493
Lamps (cont'd)On Reminder . . . . . . . . . . . . . . . . . 146
Reading . . . . . . . . . . . . . . . . . . . . . . 173
Lane Change Alert (LCA) . . . . . . . 274
Lane Departure
Warning (LDW) . . . . . . . . . . . . . . . . 276
Lane Departure Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 141
Lane Keep Assist (LKA) . . . . . . . . 278
Lane Keep Assist Light . . . . . . . . . 142
Lap-Shoulder Belt . . . . . . . . . . . . . . . 67
LATCH System
Replacing Parts after aCrash . . . . . . . . . . . . . . . . . . . . . . . 104
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . 91
LED Lighting . . . . . . . . . . . . . . . . . . . . 367
Lighting Entry . . . . . . . . . . . . . . . . . . . . . . . . . 173
Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Illumination Control . . . . . . . . . . . 172
LED . . . . . . . . . . . . . . . . . . . . . . . . . . 367
Task . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Lights Airbag Readiness . . . . . . . . . . . . . 135
Antilock Brake System(ABS) Warning . . . . . . . . . . . . . . 140
Brake System Warning . . . . . . . 139 Lights (cont'd)
Charging System . . . . . . . . . . . . . 137
Check Engine (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . 137
Cruise Control . . . . . . . . . . . . . . . . 146
Door Ajar . . . . . . . . . . . . . . . . . . . . . 147
Driver Mode Control . . . . . . . . . . 144
Electric Parking Brake . . . . . . . . 140
Electronic Stability Control (ESC), Off . . . . . . . . . . . . . . . . . . . 143
Engine Coolant Temperature Warning . . . . . . . 144
Engine Oil Pressure . . . . . . . . . . 145
Flash-to-Pass . . . . . . . . . . . . . . . . . 168
Four-Wheel-Drive . . . . . . . . . . . . . 141
Front Fog Lamp . . . . . . . . . . . . . . 146
High-Beam On . . . . . . . . . . . . . . . . 146
High/Low Beam Changer . . . . . 167
Hill Descent Control . . . . . . . . . . 141
Lane Departure Warning . . . . . . 141
Lane Keep Assist . . . . . . . . . . . . . 142
Low Fuel Warning . . . . . . . . . . . . 145
Seat Belt Reminders . . . . . . . . . . 135
Security . . . . . . . . . . . . . . . . . . . . . . 146
Service Electric Parking Brake . . . . . . . . . . . . . . . . . . . . . . . 140
Tire Pressure . . . . . . . . . . . . . . . . . 144
Tow/Haul Mode . . . . . . . . . . . . . . . 141 Lights (cont'd)
Traction Off . . . . . . . . . . . . . . . . . . . 142
Limited-Slip Differential . . . . . . . . . 242
Lock Steering Column . . . . . . . . . . . . . . . . 37
Locking Rear Axle . . . . . . . . . . . . . . 242
Locks Automatic Door . . . . . . . . . . . . . . . . . 27
Delayed Locking . . . . . . . . . . . . . . . . 27
Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Lockout Protection . . . . . . . . . . . . . . 28
Power Door . . . . . . . . . . . . . . . . . . . . . 27
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Loss of Control . . . . . . . . . . . . . . . . . 190
Low Fuel Warning Light . . . . . . . . . 145
Low-Profile Tires . . . . . . . . . . . . . . . . 380
Lower Anchors and Tethers for Children (LATCH
System) . . . . . . . . . . . . . . . . . . . . . . . . 91
Lumbar Adjustment . . . . . . . . . . . . . . 56 Front Seats . . . . . . . . . . . . . . . . . . . . . 56
M
MaintenanceRecords . . . . . . . . . . . . . . . . . . . . . . 456
Maintenance and Care Additional . . . . . . . . . . . . . . . . . . . . . 449
Maintenance Schedule . . . . . . . . . 441