2020 GMC SIERRA terrain mode

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Instruments and Controls 145
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 Overheating0351. 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 0351.
Driver Mode Control Light
This light comes on when Sport
Mode is selected (1500 Series).
This light comes on when Snow/Ice
Mode is selected.
This light comes on when Terrain
Mode is selected (1500 Series).
This light comes on when Off-Road
Mode is selected.
Tire Pressure Light

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
238 Driving and Operating
If HDC is to be used for more than
three minutes or on grades steeper
than 25%, the transfer case should
be put into Four-Wheel Drive Low (4
n) to reduce the possibility of brake
overheating.
Noise from the Electronic Brake
Control Module (EBCM) is normal
when HDC is active.
When HDC is activated, the initial
HDC speed is set to the current
driving speed. It can be increased or
decreased by pressing +RES or
SET- on the steering wheel, or by
applying the accelerator or brake
pedal. This adjusted speed
becomes the new set speed.
HDC will remain enabled between
30 and 60 km/h (19 and 37 mph);
however, vehicle speed cannot be
set or maintained in this range. HDC
will automatically disable if the
vehicle speed is above 80 km/h
(50 mph) or above 60 km/h
(37 mph) for at least 30 seconds.
5must be pressed again to
re-enable HDC. HDC may disable
after an extended period of use. If this happens, HDC will require
time to cool down. The length of
time HDC remains active depends
on road conditions, grade, set
speed, vehicle loading, and outside
temperature.
When enabled, if the vehicle speed
is above 30 km/h (19 mph) and
below 60 km/h (37 mph), a DIC
message will display.
Driver Mode Control
This feature adds a sportier feel,
provides a more comfortable ride,
or assists in different weather
conditions or terrain. Depending on
the option package, available
features, and mode selected; the
suspension, steering, and
powertrain will change settings to
achieve the desired mode
characteristics. If the vehicle is
equipped with magnetic ride control,
selecting the various Driver Modes
enhances the ride performance for
the road conditions and the
selected mode.
Mode availability is dependent upon
vehicle trim level, region, and
optional features.
Not all drive modes are available
on. 1500 series vehicles may have
Normal, Sport, Off Road, Terrain,
and Tow Haul. 2500/3500 series
vehicles may have Normal, Off
Road, and Tow/Haul.
Mode Activation
To activate and deactivate Tow/Haul
turn the Drive Mode knob to the left.
For activation of modes other than
Tow/Haul, turn the Drive Mode knob
to the right.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 239
Vehicles with the MODE graphic on
the knob will have a menu selection
screen in the instrument cluster to
select the desired mode. When the
Drive Mode knob is turned to the
right, the mode list will display and
activate the next available mode.If equipped, select Terrain Mode by
pressing the
gbelow the 4m
transfer case button.
Modes:
Normal Mode
Use for normal city and highway
driving to provide a smooth, soft
ride. This mode provides a balanced
setting between comfort and
handling. This is the standard mode
and when selected, there is no
indicator in the instrument cluster.Sport Mode
Use where road conditions or
personal preference demand a more
controlled response.
When you enter this mode you will
immediately feel a down shift. In this
mode, the vehicle also monitors
driving behaviors and automatically
enables Performance Shift Features
when spirited driving is detected.
These features maintain lower
transmission gears to increase
available engine braking and
improve acceleration response. The
vehicle will exit these features and
return to normal operation after a
short period when no spirited driving
is detected. The steering will
change to provide more precise
control. If the vehicle has Magnetic
Ride Control, the suspension will
change to provide better cornering
performance.
When selected, the Sport Mode light
displays in the instrument cluster.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
240 Driving and Operating
Off-Road Mode
Use to improve driving at moderate
speeds, on grass, gravel, dirt,
unpaved roads, or snow-covered
roads that have not been groomed
or plowed.
The accelerator pedal will be more
sensitive to provide finer control of
the torque at the wheels.
StabiliTrak/Electronic Stability
Control (ESC), the Antilock Brake
System (ABS), and the Traction
Control System (TCS) will change
for optimal off-road performance.
Use this mode for public off-road
recreational driving. SeeOff-Road
Driving 0191.
When selected, the Off-Road Mode
indicator light displays in the
instrument cluster. Tow/Haul Mode
This feature assists when pulling a
heavy trailer or a heavy load. See
Tow/Haul Mode
0226.
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle’s Gross
Combined Weight Rating (GCWR).
See “Weight of the Trailer” under
Trailer Towing 0292.
Tow/Haul Mode is most useful when
pulling a heavy trailer or a heavy
load under the following conditions:
. Through rolling terrain
. In stop-and-go traffic
. In busy parking lots where
improved low speed control of
the vehicle is desired
Operating the vehicle in Tow/Haul
Mode when lightly loaded or with no
trailer at all will not cause damage.
However, there is no benefit to
selecting Tow/Haul Mode when the
vehicle is unloaded. Such a
selection when unloaded may result
in unpleasant engine and transmission driving characteristics,
heavy or light steering, and reduced
fuel economy.
When selected, the Tow/Haul Mode
light will display in the instrument
cluster.
If the vehicle is turned off with Tow/
Haul Mode active and then restarted
within four hours or less, Tow/Haul
will remain active. Otherwise the
vehicle will start in Normal Mode.
Terrain Mode
Use for finer control during low
speed, off-road driving. When using
this mode it will mimic the
characteristics of four-wheel-drive
low (4
n) without the torque
capabilities.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
Driving and Operating 241
Use when:
.Traveling on very rough roads at
very low speeds, such as a
two-track or heavily rutted road.
. Traveling slowly in grassy fields.
. Pulling a boat out of the water
on a trailer.
. Using the vehicle for public
off-road recreational driving. See
Off-Road Driving 0191 and
Hill and Mountain Roads 0197.
When in Terrain Mode, the vehicle
will shift automatically but may hold
a lower gear longer to maximize
engine torque. The steering will
change to provide more precise
control. A unique pedal map,
transmission shift pattern, and rpm
control are utilized to give better
control at lower speeds and over
rough terrain. When the vehicle
comes to a stop, Vehicle Hold is
engaged. TCS will be optimized for
maximum torque transfer across
axles, and Active Braking During Lift
Throttle will be engaged. Active Braking During Lift Throttle:
.
Automatically applies light
braking, similar to heavy engine
braking of four-wheel-drive low.
. Applies light braking in D (Drive)
until the vehicle is at idle
speeds. In Manual L1 and
Manual L2, moderate braking
may stop the vehicle.
. Reduces trailer braking.
Terrain Mode Drive Select Expected Vehicle Behavior Ideal Terrain
Drive (L3-Lx) Minor deceleration when off
throttle and mild ability to
modulate throttle; mimics
performance of 4
nwithout
torque multiplication. Grassy fields,
mild two tracks,
rutted roads,
large rolling hills,
L2 Moderate deceleration when
off throttle and moderate
ability to modulate throttle;
will bring vehicle to a stop in
most cases. Mild rock crawling,
heavy ruts,
short, steeper grades,

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
242 Driving and Operating
Terrain ModeDrive Select Expected Vehicle Behavior Ideal Terrain
L1 Significant deceleration when
off throttle and significant
ability to modulate throttle;
will bring vehicle to a stop in
most cases.
Rock crawling downhill
Active Braking During Lift Throttle
will reduce the back and forth
between the accelerator and brake
pedals.
Vehicle Hold Features:
. When the vehicle comes to a
stop on an incline grade in
forward gear or on a decline
grade in reverse gear, Vehicle
Hold is engaged until the
accelerator pedal is pressed.
. When the vehicle is in forward
gear on a decline, the vehicle is
allowed to creep down the hill
when the brake pedal is
released without pressing the accelerator pedal. The vehicle
will also creep forward on flat
ground.
. If the driver seat belt is removed
and the driver door is opened
while the vehicle is being held,
EPB will be engaged.
. EPB will engage if the vehicle is
held for an extended period.
Terrain Mode is only available on
vehicles equipped with the single
speed transfer case.
Terrain Mode can only be
active when:
. Vehicle speed is less than
80 km/h (50 mph).
. The transfer case is in 4
m. Frequent use of this mode may
cause brake wear due to the light
braking.
The vehicle will automatically exit
the mode if the brakes get too hot.
Terrain Mode can be turned back on
after the brakes have cooled.
When Terrain Mode is selected:
.
Auto Engine Start/Stop will be
disabled.
. The Terrain Mode indicator
displays on the instrument
cluster.
Limited-Slip Differential
If equipped, the limited-slip
differential can give more traction on
snow, mud, ice, sand, or gravel.
It works like a standard axle most of
the time, but when traction is low,
this feature allows the drive wheel
with the most traction to move the
vehicle. For vehicles with the
limited-slip differential, driven under
severe conditions, the rear axle fluid
should be changed. See
Maintenance Schedule 0442.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/4/19
304 Driving and Operating
Trailer Lamps
Always check that all trailer lamps
are working at the beginning of each
trip, and periodically on longer trips.
If equipped, the Trailering App will
monitor the RH turn/brake lamp
circuit, LH turn/brake lamp circuit,
running lamp circuit, and reverse
lamp circuits on the trailer. DIC
messages and Trailering App alerts
may be displayed if lighting circuit
issues are detected on the trailer.
Pressing START LIGHT TEST in the
Trailering App automatically
activates the trailer lamps. The
Trailering App is not a substitute for
manually inspecting your trailer
lamps. SeeTrailering App 0310.
Turn Signals When Towing a
Trailer
When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing
lanes, or stopping. When towing a
trailer, the arrows on the instrument cluster will illuminate even if the
trailer is not properly connected or
the bulbs are burned out.
Tow/Haul Mode
For instructions on how to enter
Tow/Haul Mode, see
Driver Mode
Control 0238.
Tow/Haul assists when pulling a
heavy trailer or a large or heavy
load. See Tow/Haul Mode 0226.
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross
Combined Weight Rating (GCWR).
See “Trailer Weight ”under Trailer
Towing 0292.
Tow/Haul Mode is most useful when
towing a heavy trailer or carrying a
large or heavy load:
. Through rolling terrain.
. In stop-and-go traffic.
. In busy parking lots.
Operating the vehicle in Tow/Haul
Mode when lightly loaded or not
towing will not cause damage; however, it is not recommended and
may result in unpleasant engine and
transmission driving characteristics,
heavy or light steering efforts, and
reduced fuel economy.Integrated Trailer Brake
Control System
The vehicle may have an Integrated
Trailer Brake Control (ITBC) system
for use with electric trailer brakes or
most electric over hydraulic trailer
brake systems. These instructions
apply to both types of electric trailer
brakes.
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is proportional to
the amount of vehicle braking. This

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-13337776) - 2020 - CRC - 4/10/19
Vehicle Care 327
Vehicle Care
General Information
General Information . . . . . . . . . . 328
California Proposition65 Warning . . . . . . . . . . . . . . . . . 329
California Perchlorate Materials Requirements . . . . . 329
Accessories and Modifications . . . . . . . . . . . . . . . . 329
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 330
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 330
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 332
Engine Oil . . . . . . . . . . . . . . . . . . . . 339
Engine Oil Life System . . . . . . . 341
Automatic Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . . . 343
Engine Air Filter Life System . . . . . . . . . . . . . . . . . . . . . . 343
Engine Air Cleaner/Filter . . . . . . 344
Cooling System . . . . . . . . . . . . . . 346
Engine Overheating . . . . . . . . . . 351
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . 352
Engine Fan . . . . . . . . . . . . . . . . . . . 353 Power Steering Fluid . . . . . . . . . 354
Washer Fluid . . . . . . . . . . . . . . . . . 354
Brakes . . . . . . . . . . . . . . . . . . . . . . . 355
Brake Pad Life System . . . . . . . 356
Brake Fluid . . . . . . . . . . . . . . . . . . . 357
Battery - North America . . . . . . 358
Four-Wheel Drive . . . . . . . . . . . . . 361
Front Axle . . . . . . . . . . . . . . . . . . . . 361
Rear Axle . . . . . . . . . . . . . . . . . . . . 362
Noise Control System . . . . . . . . 362
Starter Switch Check . . . . . . . . . 363
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 363
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 363
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 364
Wiper Blade Replacement . . . . 364
Windshield Replacement . . . . . 365
Gas Strut(s) . . . . . . . . . . . . . . . . . . 365
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 366
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 367
Halogen Bulbs . . . . . . . . . . . . . . . . 367
LED Lighting . . . . . . . . . . . . . . . . . 367 Headlamps, Front Turn Signal,
Sidemarker, and Parking
Lamps . . . . . . . . . . . . . . . . . . . . . . 367
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 368
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 369
License Plate Lamp . . . . . . . . . . 369
Electrical System
Electrical System Overload . . . 370
Fuses and Circuit Breakers . . . 370
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 371
Instrument Panel Fuse
Block (Left) . . . . . . . . . . . . . . . . . 374
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 376
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 379
All-Season Tires . . . . . . . . . . . . . . 379
Winter Tires . . . . . . . . . . . . . . . . . . 380
Low-Profile Tires . . . . . . . . . . . . . 380
All-Terrain Tires . . . . . . . . . . . . . . . 381
Tire Sidewall Labeling . . . . . . . . 381
Tire Designations . . . . . . . . . . . . . 383
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . . . 385