warning lights GMC SIERRA 2020 User Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
310 Driving and Operating
Warning (Continued)
.If the trailer brakes are not
operating properly at any
time, or if a DIC message
indicates problems with the
trailer connections or trailer
brakes, carefully pull the
vehicle over to the side of
the road when traffic
conditions allow.
Trailer Tires
Special Trailer (ST) tires differ from
vehicle tires. Trailer tires are
designed with stiff sidewalls to help
prevent sway and to support heavy
loads. These features can make it
difficult to determine if the trailer tire
pressures are low only based on a
visual inspection.
Always check all trailer tire
pressures before each trip when the
tires are cool. Low trailer tire
pressure is a leading cause of trailer
tire blow-outs. If the vehicle is equipped with a
trailer tire pressure monitoring
system, see the trailer tire pressure
monitoring system description and
the trailering app.
Trailer tires deteriorate over time.
The trailer tire sidewall will show the
week and year the tire was
manufactured. Many trailer tire
manufacturers recommend
replacing tires more than six
years old.
Overloading is another leading
cause of trailer tire blow-outs. Never
load your trailer with more weight
than the tires are designed to
support. The load rating is located
on the trailer tire sidewall.
Always know the maximum speed
rating for the trailer tires before
driving. This may be significantly
lower than the vehicle tire speed
rating. The speed rating may be on
the trailer tire sidewall. If the speed
rating is not shown, the default
trailer tire speed rating is 105 km/h
(65 mph).
Trailering App
Trailer Light App
If equipped, the Trailer Lights App is
on the Home Page of the
infotainment display.
Touch Start to cycle the trailer lamps
on and off to determine if they are
working. The test follows this
sequence:
1. The running lights turn on first and remain on throughout the
sequence.
2. The brake lights turn on for about two seconds.
3. The left turn signal light flashes three times.
4. The right turn signal light flashes three times.
5. The reverse lights turn on for about two seconds.
6. Steps 2–5 repeat for approximately one minute and
45 seconds, or until the test
deactivates.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 311
Touch Stop to stop the test. The test
will automatically end after
one minute and 45 seconds.
The sequence also deactivates
when any of the following occur:
.The ignition is turned off.
. The transmission is shifted out
of P (Park).
. The brake pedal is pressed.
. The turn signal is activated.
. The hazard warning lights are
activated.
Trailering App
If equipped, the Trailering App is on
the Home Page of the infotainment
display.
If equipped this feature allows
profiles for connected trailers to be
created to view status, to store and
track trailer usage information, and
to set up towing assistance
features.
The Trailering App Preview will
appear when the Trailering App is
opened for the first time from the Home Page. Touch GET STARTED
in the Trailering App to go into
the app.
When a trailer is electrically
connected, there will be an option to
create a profile, use a guest profile,
or cancel. After Cancel is selected a
third time, Don’t Remind Me will
display and touching that will turn off
the trailer detection pop-up. To turn
the Trailer Detection Alert on, select
ON in the Settings tab.
When a trailer is electrically
connected and after a Trailer Profile
has been created, the trailer
detection pop-up will appear with a
list of all of the custom Trailer
Profiles made on the vehicle. To
load an existing Trailer Profile,
select one of the Trailer Profiles
listed, or load the Guest Trailer
Profile by selecting GUEST
TRAILER. Touching Cancel,
Accessory/No trailer, or shifting the
vehicle from P (Park), will select
Accessory/No trailer as the active
Trailer Profile and will dismiss the
pop- up.
Create a Trailer Profile
1. Touch Create Profile on the pop-up or touch + Add Trailer
in the Trailering App.
2. Create a name for the trailer.
3. Select the hitch type. A checklist profile will be
created based on the type
selected.
4. Select the trailer type.
A pop-up will indicate the setup is
complete. Touch DONE to complete
the process or touch TRAILER
FEATURE SETUP to set up the
Tow/Haul Mode reminder, Trailer
Tire Pressure Monitoring System,
if equipped, maintenance reminders,
or towing assistance, if equipped.
Import a Trailer Profile
A trailer profile saved to an OnStar
account can be imported to the
vehicle. 1. Touch Import Profile on the pop-up.
2. Select a trailer profile from the list.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 315
Light, Reverse Lights, and Electric
Brakes, if equipped), the view will
display OK.
Connection Problem
If any of the trailer connections are
not detected, a message about the
connection issue will appear on the
Driver Information Center (DIC). The
infotainment display will also show
the connection issue in the
Connection Status view.
Diagnose View
Touch Diagnose to see more
information about the connection
problem.
This view will display the names of
the trailer connector pins, a graphic
of the trailer connector, and a
graphic of the back of the trailer.
Any connector pin that failed will be
amber color, and the location of the
corresponding connection will be
highlighted on the graphic of the
back of the trailer.The Running Lights connection may
not detect partial outages. Activate
the light test to check all trailer
lamps. See
“Light Test”following.
If the trailer is not equipped with
reverse lights or electric brakes and
you are receiving failure messages
in the DIC or on this view, turn off
the Reverse Lights Alert or the
Electric Brakes Alert setting in the
trailer ’s profile page.
Light Test
Touch Start Light Test to cycle the
trailer lights on and off to determine
if they are working. The test follows
this sequence: 1. The running lights turn on first and remain on throughout the
sequence.
2. The brake lights turn on for about two seconds.
3. The left turn signal light flashes three times.
4. The right turn signal light flashes three times. 5. The reverse lights turn on for
about two seconds.
6. Steps 2–5 repeat for approximately one minute and
45 seconds, or until the test
deactivates.
Touch Stop to stop the test. The test
will automatically end after
one minute and 45 seconds.
The sequence also deactivates
when any of the following occur:
. The ignition is turned off.
. The transmission is shifted out
of P (Park).
. The brake pedal is pressed.
. The turn signal is activated.
. The hazard warning lights are
activated.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 4/4/19
492 Index
Extender, Seat Belt . . . . . . . . . . . . . . 71
Exterior Cargo Lamps . . . . . . . . . . 171
Exterior Lamp Controls . . . . . . . . . 165
Exterior Lamps Off Reminder . . . 167
Exterior Lighting BatterySaver . . . . . . . . . . . . . . . . . . . . . . . . . 174
F
FanEngine . . . . . . . . . . . . . . . . . . . . . . . . 353
Filter, Engine Air Cleaner . . . . . . . . . . . 344
Flash-to-Pass . . . . . . . . . . . . . . . . . . . 168
Flashers, Hazard Warning . . . . . . 169
Flat Tire . . . . . . . . . . . . . . . . . . . . . . . . 405 Changing . . . . . . . . . . . . . . . . . . . . . 407
FlexFuel
E85 . . . . . . . . . . . . . . . . . . . . . . . . . . . 282
Floor Console Storage . . . . . . . . . . 115
Floor Mats . . . . . . . . . . . . . . . . . . . . . . 438
Fluid Automatic Transmission . . . . . . 343
Brakes . . . . . . . . . . . . . . . . . . . . . . . . 357
Four-Wheel DriveTransfer Case . . . . . . . . . . . . . . . 227
Power Steering . . . . . . . . . . . . . . . 354
Washer . . . . . . . . . . . . . . . . . . . . . . . 354
Fog Lamps . . . . . . . . . . . . . . . . . . . . . 170 Folding Mirrors . . . . . . . . . . . . . . . . . . 43
Forward Collision Alert
(FCA) System . . . . . . . . . . . . . . . . . 268
Four-Wheel Drive . . . . . . . . . . 227, 361
Four-Wheel-Drive Light . . . . . . . . . 142
Frequency Statement Radio . . . . . . . . . . . . . . . . . . . . . . . . . 472
Front Axle . . . . . . . . . . . . . . . . . . . . . . 361
Front Fog Lamp Light . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Front Pedestrian Braking
(FPB) System . . . . . . . . . . . . . . . . . 272
Front Seats Adjustment . . . . . . . . . . . . . . . . . . . . . 55
Heated and Ventilated . . . . . . . . . . 61
Fuel
Additives . . . . . . . . . . . . . . . . . . . . . 282
Economy, Driving for Better . . . 186
Filling a Portable FuelContainer . . . . . . . . . . . . . . . . . . . 286
Filling the Tank . . . . . . . . . . 283, 285
Foreign Countries . . . . . . . . . . . . 281
Gauge . . . . . . . . . . . . . . . . . . . . . . . . 132
Low Fuel Warning Light . . . . . . . 146
Management, Active . . . . . . . . . . 219
Prohibited Fuels . . . . . . . . . . . . . . 281
Recommended . . . . . . . . . . 280, 281
Top Tier . . . . . . . . . . . . . . . . . . . . . . 280 Full-Size Spare Tire . . . . . . . . . . . . 418
Fuses
Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . . . . 371
Fuses and Circuit Breakers . . . 370
Instrument Panel Fuse Block . . . . . . . . . . . . . . . . . . . 374, 376G
Garage Door Opener . . . . . . . . . . . 161
Programming . . . . . . . . . . . . . . . . . 161
Gas Strut(s) . . . . . . . . . . . . . . . . . . . . 365
Gauges
Engine CoolantTemperature . . . . . . . . . . . . . . . . 134
Engine Oil Pressure . . . . . . . . . . 133
Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . 132
Odometer . . . . . . . . . . . . . . . . . . . . . 132
Speedometer . . . . . . . . . . . . . . . . . 131
Tachometer . . . . . . . . . . . . . . . . . . . 132
Trip Odometer . . . . . . . . . . . . . . . . 132
Voltmeter . . . . . . . . . . . . . . . . . . . . . 135
Warning Lights and Indicators . . . . . . . . . . . . . . . . . . . 126
General Information Service and Maintenance . . . . . 440
Towing . . . . . . . . . . . . . . . . . . . . . . . . 287
Vehicle Care . . . . . . . . . . . . . . . . . . 328

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 4/4/19
494 Index
Lamps (cont'd)On Reminder . . . . . . . . . . . . . . . . . 147
Reading . . . . . . . . . . . . . . . . . . . . . . 173
Lane Change Alert (LCA) . . . . . . . 274
Lane Departure
Warning (LDW) . . . . . . . . . . . . . . . . 276
Lane Departure Warning Light . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Lane Keep Assist (LKA) . . . . . . . . 278
Lane Keep Assist Light . . . . . . . . . 143
Lap-Shoulder Belt . . . . . . . . . . . . . . . 68
LATCH System
Replacing Parts after aCrash . . . . . . . . . . . . . . . . . . . . . . . 105
LATCH, Lower Anchors and Tethers for Children . . . . . . . . . . . . 92
LED Lighting . . . . . . . . . . . . . . . . . . . . 367
Lighting Entry . . . . . . . . . . . . . . . . . . . . . . . . . 173
Exit . . . . . . . . . . . . . . . . . . . . . . . . . . . 173
Illumination Control . . . . . . . . . . . 172
LED . . . . . . . . . . . . . . . . . . . . . . . . . . 367
Task . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Lights Airbag Readiness . . . . . . . . . . . . . 136
Antilock Brake System(ABS) Warning . . . . . . . . . . . . . . 141
Brake System Warning . . . . . . . 140 Lights (cont'd)
Charging System . . . . . . . . . . . . . 138
Check Engine (Malfunction
Indicator) . . . . . . . . . . . . . . . . . . . . 138
Cruise Control . . . . . . . . . . . . . . . . 147
Door Ajar . . . . . . . . . . . . . . . . . . . . . 148
Driver Mode Control . . . . . . . . . . 145
Electric Parking Brake . . . . . . . . 141
Electronic Stability Control (ESC), Off . . . . . . . . . . . . . . . . . . . 144
Engine Coolant Temperature Warning . . . . . . . 145
Engine Oil Pressure . . . . . . . . . . 146
Flash-to-Pass . . . . . . . . . . . . . . . . . 168
Four-Wheel-Drive . . . . . . . . . . . . . 142
Front Fog Lamp . . . . . . . . . . . . . . 147
High-Beam On . . . . . . . . . . . . . . . . 147
High/Low Beam Changer . . . . . 167
Hill Descent Control . . . . . . . . . . 142
Lane Departure Warning . . . . . . 142
Lane Keep Assist . . . . . . . . . . . . . 143
Low Fuel Warning . . . . . . . . . . . . 146
Seat Belt Reminders . . . . . . . . . . 136
Security . . . . . . . . . . . . . . . . . . . . . . 147
Service Electric Parking Brake . . . . . . . . . . . . . . . . . . . . . . . 141
Tire Pressure . . . . . . . . . . . . . . . . . 145
Tow/Haul Mode . . . . . . . . . . . . . . . 142 Lights (cont'd)
Traction Off . . . . . . . . . . . . . . . . . . . 143
Limited-Slip Differential . . . . . . . . . 242
Lock Steering Column . . . . . . . . . . . . . . . . 38
Locking Rear Axle . . . . . . . . . . . . . . 243
Locks Automatic Door . . . . . . . . . . . . . . . . . 26
Delayed Locking . . . . . . . . . . . . . . . . 26
Door . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Lockout Protection . . . . . . . . . . . . . . 27
Power Door . . . . . . . . . . . . . . . . . . . . . 26
Safety . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Loss of Control . . . . . . . . . . . . . . . . . 190
Low Fuel Warning Light . . . . . . . . . 146
Low-Profile Tires . . . . . . . . . . . . . . . . 380
Lower Anchors and Tethers for Children (LATCH
System) . . . . . . . . . . . . . . . . . . . . . . . . 92
Lumbar Adjustment . . . . . . . . . . . . . . 57 Front Seats . . . . . . . . . . . . . . . . . . . . . 57
M
MaintenanceRecords . . . . . . . . . . . . . . . . . . . . . . 457
Maintenance and Care Additional . . . . . . . . . . . . . . . . . . . . . 450
Maintenance Schedule . . . . . . . . . 442

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/-
Mexico-13337776) - 2020 - CRC - 4/4/19
Index 499
Traction Control/ElectronicStability Control . . . . . . . . . . . . . . . 235
Trailer Sway Control (TSC) . . . . . . . . . . 308
Tow Mirrors . . . . . . . . . . . . . . . . . . . . . 41
Towing . . . . . . . . . . . . . . . . . . . . . . . . 292
Trailer Towing
App . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
Trailering App . . . . . . . . . . . . . . . . . . 310
Transfer Case . . . . . . . . . . . . . . . . . . 227
Transmission Automatic . . . . . . . . . . . . . . . . . . . . . 221
Fluid, Automatic . . . . . . . . . . . . . . 343
Transportation Program, Courtesy . . . . . . . . . . . . . . . . . . . . . . 469
Trip Odometer . . . . . . . . . . . . . . . . . . 132
Truck-Camper Loading
Information . . . . . . . . . . . . . . . . . . . . 206
Turn and Lane-Change Signals . . . . . . . . . . . . . . . . . . . . . . . . 170
Turn Signal
Bulb Replacement . . . . . . . . . . . . 368U
Underseat Storage . . . . . . . . . . . . . 114
Uniform Tire Quality Grading . . . 401
Universal Remote System . . . . . . 161Operation . . . . . . . . . . . . . . . . . . . . . 164
Programming . . . . . . . . . . . . . . . . . 161
Using This Manual . . . . . . . . . . . . . . . . 2
V
Vehicle Alarm System . . . . . . . . . . . . . . . . . . 37
Canadian Owners . . . . . . . . . . . . . . . 2
Control . . . . . . . . . . . . . . . . . . . . . . . 188
Identification Number (VIN) . . . 458
Load Limits . . . . . . . . . . . . . . . . . . . 200
Messages . . . . . . . . . . . . . . . . . . . . 156
Personalization . . . . . . . . . . . . . . . 157
Remote Start . . . . . . . . . . . . . . . . . . . 24
Security . . . . . . . . . . . . . . . . . . . . . . . . 37
Speed Messages . . . . . . . . . . . . . 156
Towing . . . . . . . . . . . . . . . . . . . . . . . . 424
Vehicle Ahead Indicator . . . . . . . . 143
Vehicle Care Tire Pressure . . . . . . . . . . . . . . . . . 387
Vehicle Data Recording and Privacy . . . . . . . . . . . . . . . . . . . . . . . . 474
Vehicle Security Steering Column Lock . . . . . . . . . . 38 Ventilation, Air . . . . . . . . . . . . . . . . . . 182
Visors . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Voltmeter Gauge . . . . . . . . . . . . . . . 135
W
Warning
Brake System Light . . . . . . . . . . . 140
Caution and Danger . . . . . . . . . . . . . 3
Lane Departure (LDW) . . . . . . . 276
Warning Lights, Gauges, and Indicators . . . . . . . . . . . . . . . . . . . . . 126
Warnings
Hazard Flashers . . . . . . . . . . . . . . 169
Washer Fluid . . . . . . . . . . . . . . . . . . . 354
Wheels Alignment and Tire Balance . . 403
Different Size . . . . . . . . . . . . . . . . . 401
Replacement . . . . . . . . . . . . . . . . . 403
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 398
Where to Put the Restraint . . . . . . 91
Windows . . . . . . . . . . . . . . . . . . . . . . . . 48
Manual . . . . . . . . . . . . . . . . . . . . . . . . . 49
Power . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Rear . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
Windshield
Replacement . . . . . . . . . . . . . . . . . 365
Wiper/Washer . . . . . . . . . . . . . . . . 120