2018 GMC SIERRA ignition

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 279
Shifting Out of 4n
To shift:1. The vehicle must be stopped or moving less 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. Turn the knob to 4
m, AUTO,
or 2
m. Wait for the 4m, AUTO,
or 2
mindicator light to stop
flashing before shifting the
transmission into gear.
Caution
Shifting the transmission into gear
before the requested mode
indicator light has stopped
flashing could damage the
transfer case. If the transmission is in gear and/or
moving more than 5 km/h (3 mph),
the 4
m, AUTO, or 2mindicator light
will flash for 30 seconds but will not
complete the shift. 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. Park the vehicle on a level surface.
2. Set the parking brake and press and hold the brake
pedal. See Parking Brake
0 281.
3. Start the vehicle or turn the ignition on.
4. Shift the transmission to N (Neutral).
5. Shift the transfer case to 2
m. 6. Turn the transfer case knob
clockwise to N (Neutral) until it
stops and hold it there until the
N (Neutral) light starts blinking.
This will take at least
10 seconds. Then slowly
release the knob to the 4
n
position. The N (Neutral) light
will come on when the transfer
case shift to N (Neutral) is
complete.
7. With the engine running, verify that the transfer case is in
N (Neutral) by shifting the
transmission to R (Reverse),
then shift the transmission to
D (Drive). There should be no
movement of the vehicle while
shifting the transmission.
8. Turn the engine off, and the ignition to ACC/ACCESSORY.
9. Place the transmission shift lever in P (Park). See
Recreational Vehicle Towing
0430.
10. Turn the ignition to off.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
280 Driving and Operating
Shifting Out of N (Neutral)
To shift out of N (Neutral):1. Set the parking brake and apply the brake pedal.
2. Turn the ignition on with the engine off.
3. Shift the transmission to N (Neutral).
4. Turn the transfer case knob to the desired setting.
After the transfer case has
shifted out of N (Neutral), the
N (Neutral) light will go out.
5. Release the parking brake.
6. Start the engine and shift the transmission to the
desired gear.Brakes
Antilock Brake
System (ABS)
This vehicle has an Antilock Brake
System (ABS), an advanced
electronic braking system that helps
prevent a braking skid.
When the vehicle begins to drive
away, ABS checks itself.
A momentary motor or clicking noise
may be heard while this test is going
on, and it may even be noticed that
the brake pedal moves a little. This
is normal.
If there is a problem with ABS, this
warning light stays on. See Antilock
Brake System (ABS) Warning Light
0 152. If driving safely on a wet road and it
becomes necessary to slam on the
brakes and continue braking to
avoid a sudden obstacle, a
computer senses the wheels are
slowing down. If one of the wheels
is about to stop rolling, the computer
will separately work the brakes at
each wheel.
ABS can change the brake pressure
to each wheel, as required, faster
than any driver could. This can help
you steer around the obstacle while
braking hard.
As the brakes are applied, the
computer keeps receiving updates
on wheel speed and controls
braking pressure accordingly.
Remember: ABS does not change
the time needed to get a foot up to
the brake pedal or always decrease
stopping distance. If you get too
close to the vehicle in front of you,
there will not be enough time to
apply the brakes if that vehicle
suddenly slows or stops. Always
leave enough room up ahead to
stop, even with ABS.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 281
Using ABS
Do not pump the brakes. Just hold
the brake pedal down firmly and let
ABS work. You may hear the ABS
pump or motor operating and feel
the brake pedal pulsate. This is
normal.
Braking in Emergencies
ABS allows you to steer and brake
at the same time. In many
emergencies, steering can help
more than even the very best
braking.
Parking Brake
Set the parking brake by holding the
regular brake pedal down, then
pushing down the parking brake
pedal.
If the ignition is on, the brake
system warning light will come on.
SeeBrake System Warning Light
0 152.
Caution
Driving with the parking brake on
can overheat the brake system
and cause premature wear or
damage to brake system parts.
Make sure that the parking brake
is fully released and the brake
warning light is off before driving.
To release the parking brake, hold
the regular brake pedal down, then
push down momentarily on the
parking brake pedal until you feel
the pedal release. Slowly pull your
foot up off the parking brake pedal.
If the parking brake is not released
when you begin to drive, a DIC message will appear and a chime
will sound warning you that the
parking brake is still on.
Brake Assist
The Brake Assist feature is
designed to assist the driver in
stopping or decreasing vehicle
speed in emergency driving
conditions. This feature uses the
stability system hydraulic brake
control module to supplement the
power brake system under
conditions where the driver has
quickly and forcefully applied the
brake pedal in an attempt to quickly
stop or slow down the vehicle. The
stability system hydraulic brake
control module increases brake
pressure at each corner of the
vehicle until the ABS activates.
Minor brake pedal pulsation or
pedal movement during this time is
normal and the driver should
continue to apply the brake pedal as
the driving situation dictates. The
Brake Assist feature will
automatically disengage when the

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
288 Driving and Operating
To disable and enable Cruise
Grade Braking for the current
ignition key cycle, press and
hold the Tow/Haul button for
five seconds. A DIC message
displays.
. Vehicles with a diesel engine
have Cruise Grade Braking
enabled when Tow/Haul Mode is
on, the exhaust brake is on,
or both are on.
For other forms of descent control,
see Hill Descent Control (HDC)
0 284, Automatic Transmission
0 265, and Tow/Haul Mode 0271. Ending Cruise Control
There are four ways to end cruise
control:
.
Step lightly on the brake pedal.
. Press
*.
. Shift the transmission to
N (Neutral).
. To turn off cruise control,
press
5.
Erasing Speed Memory
The cruise control set speed is
erased from memory if
5is pressed
or the ignition is turned off.
Driver Assistance
Systems
This vehicle may have features that
work together to help avoid crashes
or reduce crash damage while
driving, backing, and parking. Read
this entire section before using
these systems.
{Warning
Do not rely on the Driver
Assistance Systems. These
systems do not replace the need
for paying attention and driving
safely. You may not hear or feel
alerts or warnings provided by
these systems. Failure to use
proper care when driving may
result in injury, death, or vehicle
damage. See Defensive Driving
0 236.
(Continued)

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 331
This symbol is on the Trailer Brake
Control Panel on vehicles with an
ITBC system. The power output to
the trailer brakes is based on the
amount of brake pressure being
applied by the vehicle’s brake
system, and on the type of trailer
brakes detected. This available
power output to the trailer brakes
can be adjusted to a wide range of
trailering situations.
The ITBC system is integrated with
the vehicle’s brake, antilock brake,
and StabiliTrak systems. In trailering
conditions that cause the vehicle’s
antilock brake or StabiliTrak
systems to activate, power sent to
the trailer's brakes will be
automatically adjusted to minimize
trailer wheel lock-up. This does not
imply that the trailer has StabiliTrak. If the vehicle’s brake, antilock brake,
or StabiliTrak systems are not
functioning properly, the ITBC
system may not be fully functional
or may not function at all. Make sure
all of these systems are fully
operational to ensure full
functionality of the ITBC system.
The ITBC system is powered
through the vehicle's electrical
system. Turning the ignition off will
also turn off the ITBC system. The
ITBC system is fully functional only
when the ignition is in ON/RUN.
{Warning
Connecting a trailer that has an
air brake system may result in
reduced or complete loss of trailer
braking. There may be an
increase in stopping distance or
trailer instability which could
result in personal injury or
damage to the vehicle, trailer,
or other property. Use the ITBC
(Continued)
Warning (Continued)
system only with electric or
electric over hydraulic trailer
brakes.
Trailer Brake Control Panel
1. Manual Trailer Brake Apply Lever
2. Trailer Gain Adjustment Buttons
The ITBC system has a control
panel on the instrument panel to the
left of the steering column. See
Instrument Panel 06. The control

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
334 Driving and Operating
If the disconnect occurs while
the vehicle is moving, this
message will continue until the
ignition is turned off. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.
. There is an electrical fault in the
wiring to the trailer brakes. This
message will continue as long
as there is an electrical fault in
the trailer wiring. This message
will also turn off if it is
acknowledged.
To determine if the electrical fault is
on the vehicle side or trailer side of
the trailer wiring harness
connection: 1. Disconnect the trailer wiring harness from the vehicle.
2. Turn the ignition off.
3. Wait 10 seconds, then turn the ignition back to RUN.
4. If the CHECK TRAILER WIRING message reappears,
the electrical fault is on the
vehicle side. If the CHECK TRAILER
WIRING message only
reappears when connecting the
trailer wiring harness to the
vehicle, the electrical fault is on
the trailer side.
SERVICE TRAILER BRAKE
SYSTEM: This message will display
when there is a problem with the
ITBC system. If this message
continues over multiple ignition
cycles, there is a problem with the
ITBC system. Have the vehicle
serviced.
If either the CHECK TRAILER
WIRING or SERVICE TRAILER
BRAKE SYSTEM message displays
while driving, the ITBC system may
not be fully functional or may not
function at all. When traffic
conditions allow, carefully pull the
vehicle over to the side of the road
and turn the ignition off. Check the
wiring connection to the trailer and
turn the ignition back on. If either of
these messages continues, either
the vehicle or trailer needs service. A GM dealer may be able to
diagnose and repair problems with
the trailer. However, any diagnosis
and repair of the trailer is not
covered under the vehicle warranty.
Contact your trailer dealer for
assistance with trailer repairs and
trailer warranty information.
Trailer Sway
Control (TSC)
Vehicles with StabiliTrak have a
Trailer Sway Control (TSC) feature.
Trailer sway is unintended
side-to-side motion of a trailer while
being towed. If the vehicle is towing
a trailer and the TSC detects that
sway is increasing, the vehicle
brakes are selectively applied at
each wheel, to help reduce
excessive trailer sway. If the vehicle
is equipped with the Integrated
Trailer Brake Control (ITBC) system,
and the trailer has the electric
actuated brake system, StabiliTrak
may also apply the trailer brakes.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Vehicle Care 341
Vehicle Care
General Information
General Information . . . . . . . . . . 342
California Proposition65 Warning . . . . . . . . . . . . . . . . . 343
California Perchlorate Materials Requirements . . . . . 343
Accessories and Modifications . . . . . . . . . . . . . . . . 343
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 344
Hood . . . . . . . . . . . . . . . . . . . . . . . . . 344
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . . 345
Engine Oil . . . . . . . . . . . . . . . . . . . . 350
Engine Oil Life System . . . . . . . 353
Automatic Transmission Fluid (6-Speed Transmission) . . . . . 354
Automatic Transmission Fluid (8-Speed Transmission) . . . . . 357
Engine Air Cleaner/Filter . . . . . . 358
Cooling System . . . . . . . . . . . . . . 359
Engine Overheating . . . . . . . . . . 363
Overheated Engine Protection Operating Mode . . . . . . . . . . . . . 364
Engine Fan . . . . . . . . . . . . . . . . . . . 365 Power Steering Fluid (1500
Series) . . . . . . . . . . . . . . . . . . . . . . 365
Power Steering Fluid (2500/ 3500 Series) . . . . . . . . . . . . . . . . 365
Washer Fluid . . . . . . . . . . . . . . . . . 366
Brakes . . . . . . . . . . . . . . . . . . . . . . . 367
Brake Fluid . . . . . . . . . . . . . . . . . . . 368
Battery - North America . . . . . . 369
Four-Wheel Drive . . . . . . . . . . . . . 370
Front Axle . . . . . . . . . . . . . . . . . . . . 370
Rear Axle . . . . . . . . . . . . . . . . . . . . 371
Noise Control System . . . . . . . . 373
Starter Switch Check . . . . . . . . . 374
Automatic Transmission Shift
Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . . . 374
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . . . 374
Park Brake and P (Park) Mechanism Check . . . . . . . . . . 375
Wiper Blade Replacement . . . . 375
Windshield Replacement . . . . . 376
Gas Strut(s) . . . . . . . . . . . . . . . . . . 376
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . . . 377
Bulb Replacement
Bulb Replacement . . . . . . . . . . . . 378
Halogen Bulbs . . . . . . . . . . . . . . . . 378 High Intensity Discharge (HID)
Lighting . . . . . . . . . . . . . . . . . . . . . 378
LED Lighting . . . . . . . . . . . . . . . . . 378
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . . . 378
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . . . . 380
Electrical System
High Voltage Devices andWiring . . . . . . . . . . . . . . . . . . . . . . . 380
Electrical System Overload . . . 380
Fuses and Circuit Breakers . . . 381
Engine Compartment Fuse Block . . . . . . . . . . . . . . . . . . . . . . . . 381
Instrument Panel Fuse Block (Right) . . . . . . . . . . . . . . . . . . . . . . 385
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . . . 386
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . . . 389
All-Season Tires . . . . . . . . . . . . . . 389
Winter Tires . . . . . . . . . . . . . . . . . . 390
Low-Profile Tires . . . . . . . . . . . . . 390
All-Terrain Tires . . . . . . . . . . . . . . . 391
Tire Sidewall Labeling . . . . . . . . 391
Tire Designations . . . . . . . . . . . . . 393

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
366 Vehicle Care
Wait for the power steering system
to cool, with the engine off, before
checking the fluid.
How to Check Power Steering
Fluid
To check the power steering fluid:1. Turn the ignition off and let the engine compartment
cool down.
2. Wipe the cap and the top of the reservoir clean.
3. Unscrew the cap and wipe the dipstick with a clean rag.
4. Replace the cap and completely tighten it.
5. Remove the cap again and look at the fluid level on the
dipstick.
The level should be between the
ADD and FULL marks. If necessary,
add only enough fluid to bring the
level up to the hashed area between
the ADD and FULL marks.
What to Use
To determine what kind of fluid to
use, see Recommended Fluids and
Lubricants 0456. Always use the
proper fluid.
Caution
Use of the incorrect fluid may
damage the vehicle and the
damages may not be covered by
the vehicle warranty. Always use
the correct fluid listed in
Recommended Fluids and
Lubricants 0456.
Washer Fluid
What to Use
When windshield washer fluid needs
to be added, be sure to read the
manufacturer's instructions before
use. Use a fluid that has sufficient
protection against freezing in an
area where the temperature may fall
below freezing.
Adding Washer Fluid
The vehicle has a low washer fluid
message on the DIC that comes on
when the washer fluid is low. The
message is displayed for
15 seconds at the start of each
ignition cycle. When the WASHER
FLUID LOW ADD FLUID message
displays, washer fluid will need to
be added to the windshield washer
fluid reservoir.
Open the cap with the washer
symbol on it. Add washer fluid until
the tank is full. See Engine
Compartment Overview 0345 for
reservoir location.