2018 GMC SIERRA electric steering

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 237
If the engine ever stops while the
vehicle is being driven, brake
normally but do not pump the
brakes. Doing so could make the
pedal harder to push down. If the
engine stops, there will be some
power brake assist but it will be
used when the brake is applied.
Once the power assist is used up, it
can take longer to stop and the
brake pedal will be harder to push.
Steering
Electric Power Steering (1500
Series)
If the vehicle has electric power
steering, it does not have power
steering fluid. Regular maintenance
is not required.
If power steering assist is lost due
to a system malfunction, the vehicle
can be steered, but may require
increased effort. See your dealer if
there is a problem.If the steering wheel is turned until it
reaches the end of its travel, and is
held in that position for an extended
period of time, power steering assist
may be reduced.
If the steering assist is used for an
extended period of time while the
vehicle is not moving, power assist
may be reduced.
Normal use of the power steering
assist should return when the
system cools down.
See your dealer if there is a
problem.Hydraulic Power Steering
(2500/3500 Series)
(2500/3500 Series
–All Regular
Cab, Double Cab/Crew Cab
without Digital Steer Assist)
The power steering system may
require maintenance. See Power
Steering Fluid (1500 Series) 0365
or Power Steering Fluid (2500/3500
Series) 0365. If power steering assist is lost
because the engine stops or the
system malfunctions, the vehicle
can be steered but may require
increased effort. See your dealer.
(2500/3500 Series
–Double Cab/
Crew Cab with Digital Steer
Assist)
The vehicle has a Digital Steer
Assist power steering system that
varies the amount of effort required
to steer the vehicle. Less steering
effort is required at slower speeds.
At faster speeds, the steering effort
increases. The system helps the
steering wheel return to center at
low speeds. Pressing the Tow/Haul
button adjusts steering effort for
driving conditions described in Tow/
Haul Mode 0271.
The power steering system may
require maintenance. See Power
Steering Fluid (1500 Series) 0365
or Power Steering Fluid (2500/3500
Series) 0365.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 257
This position locks the ignition and
steering wheel. It also locks the
transmission. The key can be
removed in LOCK/OFF.
The steering can bind with the
wheels turned off center. If this
happens, move the steering wheel
from right to left while turning the
key to ACC/ACCESSORY. If this
does not work, then the vehicle
needs service.
Do not turn the engine off when the
vehicle is moving. This may cause a
loss of power assist in the brake
and steering systems and disable
the airbags.
If the vehicle must be shut off in an
emergency:1. Brake using a firm and steady pressure. Do not pump the
brakes repeatedly. This may
deplete power assist, requiring
increased brake pedal force.
2. Shift the vehicle to N (Neutral). This can be done while the
vehicle is moving. After shifting to N (Neutral), firmly apply the
brakes and steer the vehicle to
a safe location.
3. Come to a complete stop. Shift to P (Park). Turn the ignition to
LOCK/OFF.
4. Set the parking brake. See Parking Brake 0281.
The shift lever must be in P (Park)
to turn the ignition switch to
LOCK/OFF.
{Warning
Turning off the vehicle while
moving may cause loss of power
assist in the brake and steering
systems and disable the airbags.
While driving, only shut the
vehicle off in an emergency.
If the vehicle cannot be pulled over,
and must be shut off while driving,
turn the ignition to ACC/
ACCESSORY.
Caution
Using a tool to force the key to
turn in the ignition could cause
damage to the switch or break the
key. Use the correct key, make
sure it is all the way in, and turn it
only with your hand. If the key
cannot be turned by hand, see
your dealer.
1 (ACC/ACCESSORY) : This
position lets things like the radio
and the windshield wipers operate
while the engine is off. It also
unlocks the steering wheel. Use this
position if the vehicle must be
pushed or towed.
2 (ON/RUN) : This position can be
used to operate the electrical
accessories and to display some
instrument cluster warning and
indicator lights. This position can
also be used for service and
diagnostics, and to verify the proper
operation of the malfunction
indicator lamp as may be required
for emission inspection purposes.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
258 Driving and Operating
The switch stays in this position
when the engine is running. The
transmission is also unlocked in this
position.
If the key is left in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. The vehicle may not
start if the battery is allowed to drain
for an extended period of time.
3 (START) :This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.
Starting the Engine
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
For an eAssist vehicle, see the
Silverado/Sierra eAssist
supplement.
Caution
If you add electrical parts or
accessories, you could change
the way the engine operates. Any
resulting damage would not be
covered by the vehicle warranty.
See Add-On Electrical Equipment
0 336.
Caution
If the steering wheel is turned
until it reaches the end of its
travel, and is held in that position
while starting the vehicle, damage
may occur to the power steering
system and there may be loss of
power steering assist.
Move the shift lever to P (Park) or
N (Neutral). To restart the engine
when the vehicle is already moving,
use N (Neutral) only.
Caution
Do not try to shift to P (Park) if the
vehicle is moving. If you do, you
could damage the transmission.
Shift to P (Park) only when the
vehicle is stopped.
Starting Procedure
1. Turn the ignition key to START. When the engine starts, let go
of the key. The idle speed will
go down as the engine gets
warm. Do not race the engine
immediately after starting it.
Operate the engine and
transmission gently to allow the
oil to warm up and lubricate all
moving parts.
When the low fuel warning light
is on and the FUEL LEVEL
LOW message is displayed in
the Driver Information Center
(DIC), hold the ignition switch
in the START position to
continue engine cranking.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 305
tires, and mirrors. Get familiar with
the handling and braking of the rig.
If the trailer has electric brakes, start
the combination moving and then
apply the trailer brake controller by
hand to be sure the brakes work.
During the trip, check occasionally
to be sure that the load is secure
and the lamps and any trailer
brakes still work.
Following Distance
Stay at least twice as far behind the
vehicle ahead as you would when
driving the vehicle without a trailer.
This can help to avoid heavy
braking and sudden turns.
Passing
More passing distance is needed
when towing a trailer. The
combination will not accelerate as
quickly and is longer so it is
necessary to go much farther
beyond the passed vehicle before
returning to the lane.
Backing Up
Hold the bottom of the steering
wheel with one hand. To move the
trailer to the left, move that hand to
the left. To move the trailer to the
right, move your hand to the right.
Always back up slowly and,
if possible, have someone
guide you.
Making TurnsCaution
Making very sharp turns while
trailering could cause the trailer to
come in contact with the vehicle.
The vehicle could be damaged.
Avoid making very sharp turns
while trailering.
When turning with a trailer, make
wider turns than normal. Do this so
the trailer will not strike soft
shoulders, curbs, road signs, trees,
or other objects. Avoid jerky or
sudden maneuvers. Signal well in
advance. If the trailer turn signal bulbs burn
out, the arrows on the instrument
cluster will still flash for turns. It is
important to check occasionally to
be sure the trailer bulbs are still
working.
Turn Signals When Towing a
Trailer
The turn signal indicators on the
instrument cluster flash whenever
signaling a turn or lane change.
Properly hooked up, the trailer
lamps also flash, telling other
drivers the vehicle is turning,
changing lanes, or stopping.
When towing a trailer, the arrows on
the instrument cluster flash for turns
even if the bulbs on the trailer are
burned out.
Check occasionally to be sure the
trailer bulbs are still working.

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
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
Vehicle Care 365
Caution (Continued)
attempting any repair. Repair the
cause of coolant loss, change the
oil, and reset the oil life system.
SeeEngine Oil 0350.
Engine Fan
If the vehicle has a clutched engine
cooling fan, when the clutch is
engaged, the fan spins faster to
provide more air to cool the engine.
In most everyday driving conditions,
the fan is spinning slower and the
clutch is not fully engaged. This
improves fuel economy and reduces
fan noise. Under heavy vehicle
loading, trailer towing, and/or high
outside temperatures, the fan speed
increases as the clutch more fully
engages, so an increase in fan
noise may be heard. This is normal
and should not be mistaken as the
transmission slipping or making
extra shifts. It is merely the cooling
system functioning properly. The fan will slow down when additional
cooling is not required and the
clutch disengages.
This fan noise may also be heard
when starting the engine. It will go
away as the fan clutch partially
disengages.
If the vehicle has electric cooling
fan(s), the fans may be heard
spinning at low speed during most
everyday driving. The fans may turn
off if no cooling is required. Under
heavy vehicle loading, trailer towing,
high outside temperatures,
or operation of the air conditioning
system, the fans may change to
high speed and an increase in fan
noise may be heard. This is normal
and indicates that the cooling
system is functioning properly. The
fans will change to low speed when
additional cooling is no longer
required.
The electric engine cooling fans
may run after the engine has been
turned. off. This is normal and no
service is required.
Power Steering Fluid
(1500 Series)
The vehicle has electric power
steering and does not use power
steering fluid.
Power Steering Fluid
(2500/3500 Series)
See
Engine Compartment Overview
0 345 for reservoir location.
When to Check Power Steering
Fluid
It is not necessary to regularly
check power steering fluid unless
there is a leak suspected in the
system or an unusual noise is
heard. A fluid loss in this system
could indicate a problem. Have the
system inspected and repaired.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
388 Vehicle Care
FusesUsage
19 –
20 –
22 Heating, ventilation, and air conditioning/
Auxiliary heating,
ventilation, and air
conditioning/Ignition
23 Instrument cluster/ Ignition sensing
diagnostic module/
Ignition
24 –
25 Data link connector/ Driver seat module
26 Passive entry/Passive start/Heating,
ventilation, and air
conditioning
27 – Fuses
Usage
28 –
29 Park enable/ Electrically adjustable
pedals
30 Special equipment option
31 Accessory/Run/Crank
32 Heated steering wheel
33 –
34 Instrument cluster
36 –
37 –
38 4WD transfer case electronic control
40 Left doors
41 Driver power seat Fuses
Usage
43 Left heated, cooled or ventilated seats (if
equipped)
44 Right heated, cooled or ventilated seats (if
equipped)
45 –
Relays Usage
49 Retained accessory power
50 Run/Crank