2015 GMC SIERRA DENALI check engine

Black plate (34,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-34 Vehicle Care
Automatic Transmission
Shift Lock Control
Function Check
{ WarningWhen you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could be
injured.
1. Before starting this check, be
sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Apply the parking brake. Be
ready to apply the regular brake
immediately if the vehicle begins
to move.
3. With the engine off, turn the
ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Ignition Transmission
Lock Check While parked and with the parking
brake set, try to turn the ignition to
LOCK/OFF in each shift lever
position. .
The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park). .
The ignition key should come
out only in LOCK/OFF.
Contact your dealer if service is
required. Park Brake and P (Park)
Mechanism Check
{ WarningWhen you are doing this check,
the vehicle could begin to move.
You or others could be injured
and property could be damaged.
Make sure there is room in front
of the vehicle in case it begins to
roll. Be ready to apply the regular
brake at once should the vehicle
begin to move.
Park on a fairly steep hill, with the
vehicle facing downhill. Keeping
your foot on the regular brake, set
the parking brake. .
To check the parking brake's
holding ability: With the engine
running and the transmission in
N (Neutral), slowly remove foot
pressure from the regular brake
pedal. Do this until the vehicle is
held by the parking brake only.

Black plate (35,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-35.
To check the P (Park)
mechanism's holding ability:
With the engine running, shift to
P (Park). Then release the
parking brake followed by the
regular brake.
Contact your dealer if service is
required.
Wiper Blade Replacement Windshield wiper blades should be
inspected for wear or cracking.
Replacement blades come in
different types and are removed in
different ways. For proper
windshield wiper blade length and
type, see Maintenance
Replacement Parts on page 11-14 .
{ Caution
Allowing the wiper arm to touch
the windshield when no wiper
blade is installed could damage
the windshield. Any damage that
(Continued) Caution (Continued) occurs would not be covered by
your warranty. Do not allow the
wiper arm to touch the windshield.
To replace the windshield wiper
blade:
1. Pull the windshield wiper
assembly away from the
windshield. 2. Press the button (2) in the
middle of the wiper arm
connector, and pull the wiper
blade away from the arm
connector (1).
3. Remove the wiper blade.
4. Reverse Steps 1 – 3 for wiper
blade replacement.
Glass Replacement If the windshield or front side glass
must be replaced, see your dealer
to determine the correct
replacement glass.

Black plate (41,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-41headlamp wiring checked right away
if the lamps go on and off or
remain off.
Windshield Wipers If the wiper motor overheats due to
heavy snow or ice, the windshield
wipers will stop until the motor cools
and will then restart.
Although the circuit is protected
from electrical overload, overload
due to heavy snow or ice may
cause wiper linkage damage.
Always clear ice and heavy snow
from the windshield before using the
windshield wipers.
If the overload is caused by an
electrical problem and not snow or
ice, be sure to get it fixed.
Fuses The wiring circuits in the vehicle are
protected from short circuits by
fuses. This greatly reduces the
chance of fires caused by electrical
problems. Look at the silver-colored band
inside the fuse. If the band is broken
or melted, replace the fuse. Be sure
you replace a bad fuse with a new
one of the identical size and rating.
Fuses of the same amperage can
be temporarily borrowed from
another fuse location, if a fuse goes
out. Replace the fuse as soon as
you can.
Engine Compartment
Fuse Block If the vehicle has a diesel engine,
see the Duramax diesel
supplement.
The engine compartment fuse block
is in the engine compartment, on
the driver side of the vehicle. Lift the cover to access the fuse
block.
{ Caution
Spilling liquid on any electrical
component on the vehicle may
damage it. Always keep the
covers on any electrical
component.

Black plate (87,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-87The vehicle may have a different
size spare tire than the road tires
originally installed on the vehicle.
This spare tire was developed for
use on this vehicle, so it is all right
to drive on it. If the vehicle has
four-wheel drive and a different size
spare tire is installed, drive only in
two-wheel drive.
After installing the spare tire on the
vehicle, stop as soon as possible
and check that the spare tire is
correctly inflated.
Have the damaged or flat road tire
repaired or replaced and installed
back onto the vehicle as soon as
possible so the spare tire will be
available in case it is needed again.
Do not mix tires and wheels of
different sizes, because they will not
fit. Keep your spare tire and its
wheel together. If the vehicle has a
spare tire that does not match the
original road tires and wheels in size
and type, do not include the spare in
the tire rotation. Jump Starting For more information about the
vehicle battery, see Battery on
page 10-29 .
If the vehicle's battery (or batteries)
has run down, you may want to use
another vehicle and some jumper
cables to start your vehicle. Be sure
to use the following steps to do it
safely.
{ WarningBatteries can hurt you. They can
be dangerous because: .
They contain acid that can
burn you. .
They contain gas that can
explode or ignite. .
They contain enough
electricity to burn you.
If you do not follow these steps
exactly, some or all of these
things can hurt you. { CautionIgnoring these steps could result
in costly damage to the vehicle
that would not be covered by the
vehicle warranty. Trying to start
the vehicle by pushing or pulling it
will not work, and it could damage
the vehicle.
1. Check the other vehicle. It must
have a 12-volt battery with a
negative ground system.
{ Caution
If the other vehicle does not have
a 12-volt system with a negative
ground, both vehicles can be
damaged. Only use a vehicle that
has a 12-volt system with a
negative ground for jump starting.
2. If you have a vehicle with a
diesel engine with two batteries,
you should know before you

Black plate (89,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-89
{ WarningUsing an open flame near a
battery can cause battery gas to
explode. People have been hurt
doing this, and some have been
blinded. Use a flashlight if you
need more light.
Be sure the battery has enough
water. You do not need to add
water to the battery installed in
your new vehicle. But if a battery
has filler caps, be sure the right
amount of fluid is there. If it is low,
add water to take care of that
first. If you do not, explosive gas
could be present.
Battery fluid contains acid that
can burn you. Do not get it on
you. If you accidentally get it in
your eyes or on your skin, flush
the place with water and get
medical help immediately. { WarningFans or other moving engine
parts can injure you badly. Keep
your hands away from moving
parts once the engine is running.
6. Check that the jumper cables do
not have loose or missing
insulation. If they do, you could
get a shock. The vehicles could
be damaged too.
Before you connect the cables,
here are some basic things you
should know. Positive (+) will go
to positive (+) or to a remote
positive (+) terminal if the
vehicle has one. Negative ( − )
will go to a heavy, unpainted
metal engine part or to a remote
negative ( − ) terminal if the
vehicle has one.
Do not connect positive (+) to
negative ( − ) or you will get a
short that would damage the
battery and maybe other parts too. And do not connect the
negative ( − ) cable to the
negative ( − ) terminal on the
dead battery because this can
cause sparks.
5.3L Shown, 6.0L, 6.2L, and 6.6L
Similar
7. Connect the red positive (+)
cable to the positive (+) terminal
of the vehicle with the dead
battery.
8. Do not let the other end touch
metal. Connect it to the
positive (+) terminal of the good

Black plate (93,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Vehicle Care 10-93
{ WarningShifting a four-wheel-drive
vehicle's transfer case into
N (Neutral) can cause the vehicle
to roll even if the transmission is
in P (Park). You or others could
be injured. Set the parking brake
before shifting the transfer case
to N (Neutral).
Follow these steps to dinghy tow:
1. Position the vehicle being towed
behind the tow vehicle, facing
forward and on a level surface.
2. Securely attach the vehicle
being towed to the tow vehicle.
3. Apply the parking brake and
start the engine.
4. Shift the transfer case to
N (Neutral). See “ Shifting into
N (Neutral) ” under Four-Wheel
Drive on page 9-40 for the
proper procedure. Check that
the vehicle is in N (Neutral) by shifting the transmission to
R (Reverse) and then to D
(Drive). There should be no
movement of the vehicle while
shifting.
5. With the transmission in D
(Drive), turn the ignition to ACC/
ACCESSORY.
{ CautionFailure to disconnect the negative
battery cable or to have it contact
the terminals can cause damage
to the vehicle.
6. Disconnect the negative battery
cable at the battery and secure
the nut and bolt. Cover the
negative battery post with a
non-conductive material to
prevent any contact with the
negative battery terminal.
7. Shift the transmission to
P (Park). { CautionIf the steering column is locked,
vehicle damage may occur.
8. Move the steering wheel to
make sure the steering column
is unlocked.
9. Release the parking brake.
10. Keep the ignition key in the
towed vehicle in ACC/
ACCESSORY to prevent the
steering column from locking.
Disconnecting the Towed Vehicle
Before disconnecting the towed
vehicle:
1. Park on a level surface.
2. Set the parking brake, shift the
transmission to P (Park), and
move the ignition key to OFF.
3. Connect the battery.
4. Apply the brake pedal.

Black plate (94,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
10-94 Vehicle Care 5. Start the engine, then shift the
transfer case out of N (Neutral)
to Two-Wheel Drive High. See
Four-Wheel Drive for directions
on shifting out of N (Neutral).
6. Check that the vehicle is in
Two-Wheel Drive High by
shifting the transmission to
R (Reverse) and then to D
(Drive). There should be
movement of the vehicle while
shifting.
7. Shift the transmission to
P (Park) and turn off the ignition.
8. Disconnect the vehicle from the
tow vehicle.
9. Release the parking brake.
10. Reset any lost presets.
The outside temperature
display will default to 32°F but
will reset with normal usage. Dolly Towing Front Towing (Front Wheels Off
the Ground) – Two-Wheel-Drive
Vehicles
{ Caution
If a two-wheel-drive vehicle is
towed with the rear wheels on the
ground, the transmission could be
damaged. The repairs would not
be covered by the vehicle
(Continued) Caution (Continued) warranty. Never tow the vehicle
with the rear wheels on the
ground.
Two-wheel-drive vehicles should not
be towed with the rear wheels on
the ground. Two-wheel-drive
transmissions have no provisions
for internal lubrication while being
towed.
To dolly tow a two-wheel-drive
vehicle, the vehicle must be towed
with the rear wheels on the dolly.
See “ Rear Towing (Rear Wheels Off
the Ground) ” later in this section.

Black plate (1,1)GMC 2015i Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-8431500) - 2015 - crc - 6/20/14
Service and Maintenance 11-1
Service and
Maintenance General Information General Information . . . . . . . . . . 11-1
Maintenance Schedule Maintenance Schedule . . . . . . . 11-3
Special Application Services Special Application
Services . . . . . . . . . . . . . . . . . . . . 11-8
Additional Maintenance
and Care Additional Maintenance
and Care . . . . . . . . . . . . . . . . . . . 11-9
Recommended Fluids,
Lubricants, and Parts Recommended Fluids and
Lubricants . . . . . . . . . . . . . . . . . 11-12
Maintenance Replacement
Parts . . . . . . . . . . . . . . . . . . . . . . 11-14
Maintenance Records
Maintenance Records . . . . . . 11-16 General Information This maintenance section applies to
vehicles with a gasoline engine. For
diesel engine vehicles, see the
maintenance schedule section in
the Duramax diesel supplement.
Your vehicle is an important
investment. This section describes
the required maintenance for the
vehicle. Follow this schedule to help
protect against major repair
expenses resulting from neglect or
inadequate maintenance. It may
also help to maintain the value of
the vehicle if it is sold. It is the
responsibility of the owner to have
all required maintenance performed.
Your dealer has trained technicians
who can perform required
maintenance using genuine
replacement parts. They have
up-to-date tools and equipment for
fast and accurate diagnostics. Many
dealers have extended evening and
Saturday hours, courtesy transportation, and online
scheduling to assist with service
needs.
Your dealer recognizes the
importance of providing
competitively priced maintenance
and repair services. With trained
technicians, the dealer is the place
for routine maintenance such as oil
changes and tire rotations and
additional maintenance items like
tires, brakes, batteries, and wiper
blades.
{ CautionDamage caused by improper
maintenance can lead to costly
repairs and may not be covered
by the vehicle warranty.
Maintenance intervals, checks,
inspections, recommended fluids,
and lubricants are important to
keep the vehicle in good working
condition.