service CHEVROLET SILVERADO 2015 3.G Repair Manual

Black plate (68,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/9/15
9-68 Driving and Operating
If the vehicle has a yellow fuel cap,
E85 or FlexFuel can be used in the
vehicle. SeeE85 or FlexFuel on
page 9-69.
For all vehicles except those with
the 6.2L V8 engine, use regular
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 87 or higher. Do not
use gasoline with an octane rating
below 87, as it may cause engine
damage and will lower fuel
economy.
If the vehicle has the 6.2L V8 engine
(VIN Code J), use premium
unleaded gasoline meeting ASTM
specification D4814 with a posted
octane rating of 91 or higher.
Regular unleaded gasoline rated at
87 octane or higher can be used,
but acceleration and fuel economy
will be reduced, and an audible
knocking noise may be heard. If this
occurs, use a gasoline rated at
91 octane or higher as soon as
possible. Otherwise, the engine
could be damaged. If heavy knocking is heard when using
gasoline with a 91 octane rating or
higher, the engine needs service.
Use of Seasonal Fuels
Use summer and winter fuels in the
appropriate season. The fuels
industry automatically modifies the
fuel for the appropriate season.
If fuel is left in the vehicle tank for
long periods of time, driving or
starting could be affected. Drive the
vehicle until the fuel is at one-half
tank or less, then refuel with the
current seasonal fuel.
Prohibited Fuels
Gasolines containing oxygenates
such as ethers and ethanol, as well
as reformulated gasolines, are
available in some cities. If these
gasolines comply with the
previously described specification,
then they are acceptable to use.
However, E85 (85% ethanol) and
other fuels containing more than
15% ethanol must be used only in
FlexFuel vehicles.{Caution
Do not use fuel containing
methanol. It can corrode metal
parts in the fuel system and also
damage plastic and rubber parts.
That damage would not be
covered under the vehicle
warranty.
Some gasolines, mainly high octane
racing gasolines, can contain an
octane-enhancing additive called
methylcyclopentadienyl manganese
tricarbonyl (MMT). Do not use
gasolines and/or fuel additives with
MMT as they can reduce spark plug
life and affect emission control
system performance. The
malfunction indicator lamp may turn
on. If this occurs, see your dealer
for service.

Black plate (75,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/9/15
Driving and Operating 9-75
immediately after towing at high
altitude on steep uphill grades, the
vehicle may show signs similar to
engine overheating. To avoid this,
let the engine run while parked,
preferably on level ground, with the
transmission in P (Park) for a few
minutes before turning the engine
off. If the overheat warning comes
on, seeEngine Overheating on
page 10-25.
Parking on Hills
{Warning
Parking the vehicle on a hill with
the trailer attached can be
dangerous. If something goes
wrong, the rig could start to move.
People can be injured, and both
the vehicle and the trailer can be
damaged. When possible, always
park the rig on a flat surface. If parking the rig on a hill:
1. Press the brake pedal, but do
not shift into P (Park) yet. Turn
the wheels into the curb if facing
downhill or into traffic if facing
uphill.
2. Have someone place chocks under the trailer wheels.
3. When the wheel chocks are in place, release the regular brakes
until the chocks absorb the load.
4. Reapply the brake pedal. Then apply the parking brake and shift
into P (Park).
5. Release the brake pedal.
Leaving After Parking on a Hill
1. Apply and hold the brake pedal.
2. Start the engine.
3. Shift into a gear.
4. Release the parking brake.
5. Let up on the brake pedal.
6. Drive slowly until the trailer is clear of the chocks. 7. Stop and have someone pick up
and store the chocks.
Maintenance when Trailer
Towing
The vehicle needs service more
often when pulling a trailer. See
Maintenance Schedule on
page 11-3. Things that are
especially important in trailer
operation are automatic
transmission fluid, engine oil, axle
lubricant, belts, cooling system, and
brake system. It is a good idea to
inspect these before and during
the trip.
Check periodically to see that all
hitch nuts and bolts are tight.
Trailer Towing
If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
If the vehicle is bi-fuel, see the
bi-fuel supplement.

Black plate (94,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/9/15
9-94 Driving and Operating
If the vehicle is equipped with the
heavy-duty trailering option, see
“Heavy-Duty Trailer Wiring Harness
Package”earlier in this section.
When the camper-wiring harness is
ordered without the heavy-duty
trailering package, a seven-wire
harness with a seven-pin connector
is at the rear of the vehicle and is
tied to the vehicle's frame.
Electric Brake Control Wiring
Provisions
These wiring provisions are
included with the vehicle as part of
the trailer wiring package. These
provisions are for an electric brake
controller.
The harness should be installed by
your dealer or a qualified service
center.
Tow/Haul Mode
Pressing this button at the end of
the shift lever turns on and off the
Tow/Haul Mode.
This indicator light on the instrument
cluster comes on when the Tow/
Haul Mode is on. Tow/Haul is a feature that assists
when pulling a heavy trailer or a
large or heavy load. See
Tow/Haul
Mode on page 9-40.
Tow/Haul 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 on page 9-75. Tow/
Haul is most useful under the
following driving conditions:
.When pulling a heavy trailer or a
large or heavy load through
rolling terrain.
.When pulling a heavy trailer or a
large or heavy load in
stop-and-go traffic.
.When pulling a heavy trailer or a
large or heavy load in busy
parking lots where improved low
speed control of the vehicle is
desired.

Black plate (97,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/9/15
Driving and Operating 9-97
.A trailer with electric brakes has
become disconnected (a
CHECK TRAILER WIRING
message will also display on
the DIC).
.There is a fault present in the
wiring to the trailer brakes (a
CHECK TRAILER WIRING
message will also display on
the DIC).
.The ITBC system is not working
due to a fault (a SERVICE
TRAILER BRAKE SYSTEM
message will also display in
the DIC).
Manual Trailer Brake Apply
The Manual Trailer Brake Apply
Lever is used to apply the trailer ’s
electric brakes independent of the
vehicle’s brakes. Sliding the lever to
the left will apply only the trailer
brakes. Use this lever to adjust
Trailer Gain to properly adjust the
power output to the trailer brakes. The 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.
{Warning
Trailer 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.

Black plate (98,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/9/15
9-98 Driving and Operating
3. Readjust Trailer Gain anytimevehicle 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.
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 inthe 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

Black plate (99,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/9/15
Driving and Operating 9-99
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
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.
If TSC is enabled, the Traction
Control System (TCS)/StabiliTrak
warning light will flash on the
instrument cluster. Vehicle speed
must be reduced. If trailer sway
continues, StabiliTrak can reduce
engine torque to help slow the
vehicle. SeeTraction Control/
Electronic Stability Control on
page 9-54.
{Warning
Even if the vehicle is equipped
with TSC, trailer sway could result
in loss of control and the vehicle
could crash. If excessive trailer
sway is detected, slow down to a
safe speed. Check the trailer and
vehicle to help correct possible
causes. These could include an
improperly or overloaded trailer,
unrestrained cargo, improper
trailer hitch configuration,
excessive vehicle-trailer speed,
or improperly inflated or incorrect
vehicle or trailer tires. See Towing
Equipment on page 9-90 for
trailer ratings and hitch setup
recommendations.
Adding non-dealer accessories can
affect the vehicle performance. See
Accessories and Modifications on
page 10-3.

Black plate (1,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/6/15
Vehicle Care 10-1
Vehicle Care
General Information
General Information . . . . . . . . . . 10-2
California Proposition65 Warning . . . . . . . . . . . . . . . . . 10-2
California Perchlorate Materials Requirements . . . . 10-3
Accessories and Modifications . . . . . . . . . . . . . . . 10-3
Vehicle Checks
Doing Your OwnService Work . . . . . . . . . . . . . . . 10-4
Hood . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Engine Compartment Overview . . . . . . . . . . . . . . . . . . . 10-6
Engine Oil . . . . . . . . . . . . . . . . . . 10-11
Engine Oil Life System . . . . . 10-14
Automatic Transmission Fluid (6 Speed
Transmission) . . . . . . . . . . . . . 10-15
Automatic Transmission Fluid (8 Speed
Transmission) . . . . . . . . . . . . . 10-18
Manual Transmission Fluid . . . . . . . . . . . . . . . . . . . . . . 10-19
Hydraulic Clutch . . . . . . . . . . . . 10-19 Engine Air Cleaner/Filter . . . . 10-19
Cooling System . . . . . . . . . . . . 10-20
Engine Coolant . . . . . . . . . . . . . 10-22
Engine Overheating . . . . . . . . 10-25
Overheated Engine
Protection
Operating Mode . . . . . . . . . . . 10-27
Engine Fan . . . . . . . . . . . . . . . . . 10-27
Power Steering Fluid (1500 Series) . . . . . . . . . . . . . . . . . . . . 10-28
Power Steering Fluid (2500/ 3500 Series) . . . . . . . . . . . . . . 10-28
Washer Fluid . . . . . . . . . . . . . . . 10-29
Brakes . . . . . . . . . . . . . . . . . . . . . 10-29
Brake Fluid . . . . . . . . . . . . . . . . . 10-30
Battery - North America . . . . 10-32
Four-Wheel Drive . . . . . . . . . . . 10-33
Front Axle . . . . . . . . . . . . . . . . . . 10-33
Rear Axle . . . . . . . . . . . . . . . . . . 10-34
Noise Control System . . . . . . 10-35
Starter Switch Check . . . . . . . 10-36
Automatic Transmission Shift Lock Control Function
Check . . . . . . . . . . . . . . . . . . . . . 10-37
Ignition Transmission Lock Check . . . . . . . . . . . . . . . . . . . . . 10-37 Park Brake and P (Park)
Mechanism Check . . . . . . . . 10-38
Wiper Blade Replacement . . . . . . . . . . . . . . 10-38
Glass Replacement . . . . . . . . 10-39
Headlamp Aiming
Headlamp Aiming . . . . . . . . . . 10-39
Bulb Replacement
Bulb Replacement . . . . . . . . . . 10-39
Halogen Bulbs . . . . . . . . . . . . . . 10-39
Headlamps, Front Turn
Signal, Sidemarker, and
Parking Lamps . . . . . . . . . . . . 10-40
Fog Lamps . . . . . . . . . . . . . . . . . 10-40
Taillamps (Chassis Cab Models) . . . . . . . . . . . . . . . . . . . 10-41
Taillamps, Turn Signal, Stoplamps, and Back-Up
Lamps . . . . . . . . . . . . . . . . . . . . 10-41
Center High-Mounted Stoplamp (CHMSL) and
Cargo Lamp . . . . . . . . . . . . . . 10-42
Replacement Bulbs . . . . . . . . . 10-43
Electrical System
Electrical System Overload . . . . . . . . . . . . . . . . . . 10-44
Fuses . . . . . . . . . . . . . . . . . . . . . . 10-44

Black plate (2,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/6/15
10-2 Vehicle Care
Engine Compartment FuseBlock . . . . . . . . . . . . . . . . . . . . . 10-44
Instrument Panel Fuse Block (Left) . . . . . . . . . . . . . . . 10-49
Instrument Panel Fuse Block
(Right) . . . . . . . . . . . . . . . . . . . . 10-51
Wheels and Tires
Tires . . . . . . . . . . . . . . . . . . . . . . . . 10-53
All-Season Tires . . . . . . . . . . . . 10-54
Winter Tires . . . . . . . . . . . . . . . . 10-55
Low-Profile Tires . . . . . . . . . . . 10-55
All-Terrain Tires . . . . . . . . . . . . 10-55
Tire Sidewall Labeling . . . . . . 10-56
Tire Designations . . . . . . . . . . . 10-58
Tire Terminology andDefinitions . . . . . . . . . . . . . . . . 10-60
Tire Pressure . . . . . . . . . . . . . . . 10-62
Tire Pressure for High-Speed Operation . . . . . . . . . . . . . . . . . 10-64
Tire Pressure Monitor System . . . . . . . . . . . . . . . . . . . 10-64
Tire Pressure Monitor Operation . . . . . . . . . . . . . . . . . 10-65
Tire Inspection . . . . . . . . . . . . . . 10-69
Tire Rotation . . . . . . . . . . . . . . . 10-69
Dual Tire Rotation . . . . . . . . . . 10-71
When It Is Time for New Tires . . . . . . . . . . . . . . . . . . . . . . 10-71 Buying New Tires . . . . . . . . . . . 10-72
Different Size Tires and
Wheels . . . . . . . . . . . . . . . . . . . 10-74
Uniform Tire Quality Grading . . . . . . . . . . . . . . . . . . . 10-75
Wheel Alignment and Tire Balance . . . . . . . . . . . . . . . . . . . 10-76
Wheel Replacement . . . . . . . . 10-76
Tire Chains . . . . . . . . . . . . . . . . . 10-77
If a Tire Goes Flat . . . . . . . . . . 10-78
Tire Changing . . . . . . . . . . . . . . 10-80
Full-Size Spare Tire . . . . . . . . 10-90
Jump Starting
Jump Starting - North America . . . . . . . . . . . . . . . . . . . 10-91
Towing the Vehicle
Towing the Vehicle . . . . . . . . . 10-95
Recreational VehicleTowing . . . . . . . . . . . . . . . . . . . . 10-95
Appearance Care
Exterior Care . . . . . . . . . . . . . . 10-101
Interior Care . . . . . . . . . . . . . . . 10-106
Floor Mats . . . . . . . . . . . . . . . . 10-109
General Information
For service and parts needs, visit
your dealer. You will receive
genuine GM parts and GM-trained
and supported service people.
Genuine GM parts have one of
these marks:
California Proposition
65 Warning
WARNING: Most motor vehicles,
including this one, contain and/or
emit chemicals known to the State

Black plate (4,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/6/15
10-4 Vehicle Care
Vehicle Checks
Doing Your Own
Service Work
{Warning
It can be dangerous to work on
your vehicle if you do not have
the proper knowledge, service
manual, tools, or parts. Always
follow owner manual procedures
and consult the service manual
for your vehicle before doing any
service work.
If doing some of your own service
work, use the proper service
manual. It tells you much more
about how to service the vehicle
than this manual can. To order the
proper service manual, see Service
Publications Ordering Information
on page 13-11. This vehicle has an airbag system.
Before attempting to do your own
service work, see
Servicing the
Airbag-Equipped Vehicle on
page 3-34.
Keep a record with all parts receipts
and list the mileage and the date of
any service work performed. See
Maintenance Records on
page 11-16.
{Caution
Even small amounts of
contamination can cause damage
to vehicle systems. Do not allow
contaminants to contact the fluids,
reservoir caps, or dipsticks.
Hood
To open the hood:
1. Pull the handle with this symbol on it. It is inside the vehicle
under the steering wheel.

Black plate (12,1)Chevrolet 2015i Silverado Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8425172) - 2015 - crc - 2/6/15
10-12 Vehicle Care
Checking Engine Oil
It is a good idea to check the engine
oil level at each fuel fill. In order to
get an accurate reading, the vehicle
must be on level ground. The
engine oil dipstick handle is a loop.
SeeEngine Compartment Overview
on page 10-6 for the location of the
engine oil dipstick.
If a low oil message displays on the
DIC, it is important to park on level
ground to accurately measure the
oil level on the dipstick. Idling the
vehicle on steep grades for a long
time can influence the level sensing
accuracy.
Obtaining an accurate oil level
reading is essential:
1. If the engine has been running recently, turn off the engine and
allow several minutes for the oil
to drain back into the oil pan.
Checking the oil level too soon
after engine shutoff will not
provide an accurate oil level
reading.{Warning
The engine oil dipstick handle
may be hot; it could burn you.
Use a towel or glove to touch the
dipstick handle.
2. Pull out the dipstick and wipe it with a clean paper towel or cloth,
then push it back in all the way.
Remove it again, keeping the tip
down, and check the level.
When to Add Engine Oil
If the oil is below the cross-hatched
area at the tip of the dipstick, add
1 L (1 qt) of the recommended oil
and then recheck the level. See
“Selecting the Right Engine Oil” in
this section for an explanation of what kind of oil to use. For engine
oil crankcase capacity, see
Capacities and Specifications on
page 12-2.
{Caution
Do not add too much oil. Oil
levels above or below the
acceptable operating range
shown on the dipstick are harmful
to the engine. If you find that you
have an oil level above the
operating range, i.e., the engine
has so much oil that the oil level
gets above the cross-hatched
area that shows the proper
operating range, the engine could
be damaged. You should drain
out the excess oil or limit driving
of the vehicle and seek a service
professional to remove the
excess amount of oil.
See Engine Compartment Overview
on page 10-6 for the location of the
engine oil fill cap.