2018 GMC SIERRA DENALI lock

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 333The trailer's and the vehicle's brake
lamps will come on when either
vehicle brakes or manual trailer
brakes are applied.
Trailer Gain Adjustment Procedure
Trailer Gain should be set for a
specific trailering condition and must
be adjusted anytime vehicle loading,
trailer loading, or road surface
conditions change.
{ WarningTrailer brakes that are
over-gained or under-gained may
not stop the vehicle and the trailer
as intended and can result in a
crash. Always follow the
instructions to set the Trailer Gain
for the proper trailer stopping
performance.
Use the following to adjust Trailer
Gain for each towing condition:
1. Drive the vehicle with the trailer
attached on a level road
surface representative of the
towing condition and free of traffic at about 32 to 40 km/h
(20 to 25 mph) and fully apply
the Manual Trailer Brake Apply
Lever.
Adjusting Trailer Gain at
speeds lower than 32 to
40 km/h (20 to 25 mph) may
result in an incorrect gain
setting.
2. Adjust the Trailer Gain, using
the Trailer Gain Adjustment
Buttons, to just below the point
of trailer wheel lock-up,
indicated by trailer wheel
squeal or tire smoke when a
trailer wheel locks.
Trailer wheel lock-up may not
occur if towing a heavily loaded
trailer. In this case, adjust the
Trailer Gain to the highest
allowable setting for the towing
condition.
3. Readjust Trailer Gain anytime
vehicle loading, trailer loading,
or road surface conditions
change or if trailer wheel
lock-up is noticed at any time
while towing. Other ITBC-Related DIC Messages
In addition to displaying TRAILER
GAIN and OUTPUT through the
DIC, trailer connection and ITBC
system status are displayed on
the DIC.
TRAILER CONNECTED: This
message will briefly display when a
trailer with electric brakes is first
connected to the vehicle. This
message will automatically turn off
in about 10 seconds. This message
can be acknowledged before it
automatically turns off.
CHECK TRAILER WIRING: This
message will display if:
.
The ITBC system first
determines connection to a
trailer with electric brakes and
then the trailer harness becomes
disconnected from the vehicle.
If the disconnect occurs while
the vehicle is stationary, this
message will automatically turn
off in about 30 seconds. This
message will also turn off if it is
acknowledged or if the trailer
harness is reconnected.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
Driving and Operating 337
Adding a Snow Plow or
Similar Equipment CautionDo not exceed 72 km/h (45 mph)
with a snow plow mounted to the
vehicle. The vehicle could
overheat and be damaged.
Before installing a snow plow on the
vehicle, follow these guidelines:
CautionIf the vehicle does not have the
snow plow prep package, RPO
VYU, adding a plow can damage
the vehicle, and the repairs would
not be covered by the vehicle
warranty. Unless the vehicle was
built to carry a snow plow, do not
add one to the vehicle. If the
vehicle has RPO VYU, then the
payload the vehicle can carry will
be reduced when a snow plow is
(Continued) Caution (Continued) installed. The vehicle can be
damaged if either the front or rear
axle ratings or the Gross Vehicle
Weight Rating (GVWR) are
exceeded.
The plow the vehicle can carry
depends on many things, such as:
.
The options the vehicle came
with, and the weight of those
options.
.
The weight and number of
passengers to be carried.
.
The weight of items added to the
vehicle, like a tool box or
truck cap.
.
The total weight of any
additional cargo to be carried.
For example, if the snow plow
weighs 318 kg (700 lb), the total
weight of all occupants and cargo
inside the cab should not exceed
135 kg (300 lb). This means that you
may only be able to carry one
passenger. Even this may be too much if there is other equipment
already adding to the weight of the
vehicle.
To safely carry a snow plow on the
vehicle:
.
Follow all aftermarket snow plow
manufacturer ’ s instructions for
the operation and transportation
of the snow plow.
.
With a snow plow attached, the
engine coolant temperature
gauge may show a higher
temperature than while driving
without one. The snow plow
could block the airflow to the
radiator. This could be more
noticeable as vehicle speed
increases. At speeds above
72 km (45 mph), this may cause
the engine coolant to overheat.
.
To increase the airflow, move the
snow plow blade postion.
.
If driving more than 24 km
(15 mi), angle the plow blade
position.

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 Proposition
65 Warning . . . . . . . . . . . . . . . . . 343
California Perchlorate
Materials Requirements . . . . . 343
Accessories and
Modifications . . . . . . . . . . . . . . . . 343
Vehicle Checks Doing Your Own
Service 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 and
Wiring . . . . . . . . . . . . . . . . . . . . . . . 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 343
California Proposition
65 Warning
{ WarningMost motor vehicles, including
this one, as well as many of its
service parts and fluids, contain
and/or emit chemicals known to
the State of California to cause
cancer and birth defects or other
reproductive harm. Engine
exhaust, many parts and
systems, many fluids, and some
component wear by-products
contain and/or emit these
chemicals. For more information
go to www.P65Warnings.ca.gov/
passenger-vehicle.
See Battery - North America 0 369
and Jump Starting - North America
0 426 and the back cover. California Perchlorate
Materials Requirements Certain types of automotive
applications, such as airbag
initiators, seat belt pretensioners,
and lithium batteries contained in
Remote Keyless Entry transmitters,
may contain perchlorate materials.
Special handling may be necessary.
For additional information, see
www.dtsc.ca.gov/hazardouswaste/
perchlorate.
Accessories and
Modifications Adding non-dealer accessories or
making modifications to the vehicle
can affect vehicle performance and
safety, including such things as
airbags, braking, stability, ride and
handling, emissions systems,
aerodynamics, durability, and
electronic systems like antilock
brakes, traction control, and stability
control. These accessories or
modifications could even cause
malfunction or damage not covered
by the vehicle warranty. Damage to suspension components
caused by modifying vehicle height
outside of factory settings will not be
covered by the vehicle warranty.
Damage to vehicle components
resulting from modifications or the
installation or use of non-GM
certified parts, including control
module or software modifications, is
not covered under the terms of the
vehicle warranty and may affect
remaining warranty coverage for
affected parts.
GM Accessories are designed to
complement and function with other
systems on the vehicle. See your
dealer to accessorize the vehicle
using genuine GM Accessories
installed by a dealer technician.
Also, see Adding Equipment to the
Airbag-Equipped Vehicle 0 90 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
346 Vehicle Care 1. Positive (+) Terminal. See
Jump Starting - North America
0 426 .
2. Battery - North America 0 369 .
3. Coolant Surge Tank and
Pressure Cap. See Cooling
System 0 359 .
4. Engine Air Cleaner/Filter 0 358 .
5. Automatic Transmission
Dipstick (If Equipped). See
“ How to Check Automatic
Transmission Fluid ” under
Automatic Transmission Fluid
(6-Speed Transmission) 0 354
or Automatic Transmission
Fluid (8-Speed Transmission)
0 357 . 6. Remote Negative ( – ) Location.
See Jump Starting - North
America 0 426 .
7. Engine Cooling Fans (Out of
View). See Cooling System
0 359 .
8. Engine Oil Fill Cap. See “ When
to Add Engine Oil ” under
Engine Oil 0 350 .
9. Engine Oil Dipstick. See
“ Checking Engine Oil ” under
Engine Oil 0 350 . 10. Brake Fluid Reservoir. See
Brake Fluid 0 368 .
11. Windshield Washer Fluid
Reservoir. See “ Adding Washer
Fluid ” under Washer Fluid
0 366 .
12. Engine Compartment Fuse
Block 0 381 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
348 Vehicle Care 1. Positive (+) Terminal. See
Jump Starting - North America
0 426 .
2. Battery - North America 0 369 .
3. Coolant Surge Tank and
Pressure Cap. See Cooling
System 0 359 .
4. Engine Air Cleaner/Filter 0 358 .
5. Automatic Transmission
Dipstick (If Equipped). See
“ How to Check Automatic
Transmission Fluid ” under
Automatic Transmission Fluid
(6-Speed Transmission) 0 354
or Automatic Transmission
Fluid (8-Speed Transmission)
0 357 . 6. Remote Negative ( – ) Location
(Out of View). See Jump
Starting - North America 0 426 .
7. Engine Cooling Fans (Out of
View). See Cooling System
0 359 .
8. Engine Oil Fill Cap. See “ When
to Add Engine Oil ” under
Engine Oil 0 350 .
9. Engine Oil Dipstick. See
“ Checking Engine Oil ” under
Engine Oil 0 350 . 10. Windshield Washer Fluid
Reservoir. See “ Adding Washer
Fluid ” under Washer Fluid
0 366 .
11. Brake Fluid Reservoir. See
Brake Fluid 0 368 .
12. Engine Compartment Fuse
Block 0 381 .

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
350 Vehicle Care 1. Positive (+) Terminal. See
Jump Starting - North America
0 426 .
2. Battery - North America 0 369 .
3. Coolant Surge Tank and
Pressure Cap. See Cooling
System 0 359 .
4. Engine Air Cleaner/Filter 0 358 .
5. Automatic Transmission
Dipstick (If Equipped). See
“ How to Check Automatic
Transmission Fluid ” under
Automatic Transmission Fluid
(6-Speed Transmission) 0 354
or Automatic Transmission
Fluid (8-Speed Transmission)
0 357 .
6. Engine Oil Dipstick. See
“ Checking Engine Oil ” under
Engine Oil 0 350 .
7. Engine Oil Fill Cap. See “ When
to Add Engine Oil ” under
Engine Oil 0 350 .
8. Engine Cooling Fan (Out of
View). See Cooling System
0 359 . 9. Remote Negative ( – ) Location.
See Jump Starting - North
America 0 426 .
10. Power Steering Fluid
Reservoir. See Power Steering
Fluid (1500 Series) 0 365 or
Power Steering Fluid (2500/
3500 Series) 0 365 .
11. Windshield Washer Fluid
Reservoir. See “ Adding Washer
Fluid ” under Washer Fluid
0 366 .
12. Brake Fluid Reservoir. See
Brake Fluid 0 368 .
13. Auxiliary Battery (If Equipped).
See Battery - North America
0 369 .
14. Engine Compartment Fuse
Block 0 381 .
If the vehicle has a diesel engine
and/or an Allison Transmission, see
the Duramax diesel supplement.
For an eAssist vehicle, see the
Silverado/Sierra supplement. Engine Oil For diesel engine vehicles, see
“ Engine Oil ” in the Duramax diesel
supplement.
To ensure proper engine
performance and long life, careful
attention must be paid to engine oil.
Following these simple, but
important steps will help protect
your investment:
.
Use engine oil approved to the
proper specification and of the
proper viscosity grade. See
“ Selecting the Right Engine Oil ”
in this section.
.
Check the engine oil level
regularly and maintain the
proper oil level. See “ Checking
Engine Oil ” and “ When to Add
Engine Oil ” in this section.
.
Change the engine oil at the
appropriate time. See Engine Oil
Life System 0 353 .
.
Always dispose of engine oil
properly. See “ What to Do with
Used Oil ” in this section.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-11349177) - 2018 - CRC - 10/17/17
356 Vehicle Care procedure at the first opportunity.
Use this cold check procedure to
check fluid level when the
transmission temperature is
between 27 °C and 32 °C (80 °F and
90 °F).
1. Locate the transmission
dipstick at the rear of the
engine compartment, on the
passenger side of the vehicle.
See Engine Compartment
Overview 0 345 .
2. Flip the handle up, then pull out
the dipstick and wipe it with a
clean rag or paper towel.
3. Install the dipstick by pushing it
back in all the way; wait
three seconds, and then pull it
back out again. 4. Check both sides of the
dipstick and read the lower
level. Repeat the check
procedure to verify the reading.
5. If the fluid level is below the
COLD check band, add only
enough fluid as necessary to
bring the level into the COLD
band. It does not take much
fluid, generally less than 0.5 L
(1 pt). Do not overfill.
6. Perform a hot check at the first
opportunity after the
transmission reaches a normal
operating temperature between
71 °C to 93 °C (160 °F to
200 °F). 7. If the fluid level is in the
acceptable range, push the
dipstick back in all the way,
then flip the handle down to
lock the dipstick in place.
Hot Check Procedure
Use this procedure to check the
transmission fluid level when the
transmission fluid temperature is
between 71 °C and 93 °C (160 °F
and 200 °F).
The hot check is the most accurate
method to check the fluid level. The
hot check should be performed at
the first opportunity in order to verify
the cold check. The fluid level rises
as fluid temperature increases, so it
is important to ensure the
transmission temperature is within
range.