check engine GMC SIERRA DENALI 2019 User Guide

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
150 Instruments and Controls If towing a trailer, reduce the
amount of cargo being hauled as
soon as possible.
If the light continues to flash, find a
safe place to park. Turn the vehicle
off and wait at least 10 seconds
before restarting the engine. If the
light is still flashing, follow the
previous guidelines and see your
dealer for service as soon as
possible.
If the light is on steady : A
malfunction has been detected.
Diagnosis and service may be
required.
Check the following:
.
If fuel has been added to the
vehicle using the capless funnel
adapter, make sure that it has
been removed. See “ Filling the
Tank with a Portable Gas Can ”
under Filling the Tank 0 273 .
The diagnostic system can
detect if the adapter has been
left installed in the vehicle,
allowing fuel to evaporate into the atmosphere. A few driving
trips with the adapter removed
may turn off the light.
.
Poor fuel quality can cause
inefficient engine operation and
poor driveability, which may go
away once the engine is warmed
up. If this occurs, change the
fuel brand. It may require at
least one full tank of the proper
fuel to turn the light off.
See Recommended Fuel
(Except 6.2L V8 Engine) 0 271
or Recommended Fuel (6.2L
V8 Engine) 0 271 .
If the light remains on, see your
dealer.
Emissions Inspection and
Maintenance Programs If the vehicle requires an Emissions
Inspection/Maintenance test, the
test equipment will likely connect to
the vehicle's Data Link
Connector (DLC). The DLC is under the instrument
panel to the left of the steering
wheel. Connecting devices that are
not used to perform an Emissions
Inspection/Maintenance test or to
service the vehicle may affect
vehicle operation. See Add-On
Electrical Equipment 0 306 . See
your dealer if assistance is needed.
The vehicle may not pass
inspection if:
.
The light is on when the engine
is running.
.
The light does not come on
when the ignition is on while the
engine is off.
.
Critical emission control systems
have not been completely
diagnosed. If this happens, the
vehicle would not be ready for
inspection and might require
several days of routine driving

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/15/18
Instruments and Controls 157
Engine Oil Pressure Light
(Uplevel Cluster) CautionLack of proper engine oil
maintenance can damage the
engine. Driving with the engine oil
low can also damage the engine.
The repairs would not be covered
by the vehicle warranty. Check
the oil level as soon as possible.
Add oil if required, but if the oil
level is within the operating range
and the oil pressure is still low,
have the vehicle serviced. Always
follow the maintenance schedule
for changing engine oil. This light should come on briefly as
the engine is started. If it does not
come on, have the vehicle serviced
by your dealer.
If the light comes on and stays on, it
means that oil is not flowing through
the engine properly. The vehicle
could be low on oil and might have
some other system problem. See
your dealer.
Low Fuel Warning Light
This light is near the fuel gauge and
comes on briefly when the ignition is
turned on as a check to show it is
working.
It also comes on when the fuel tank
is low on fuel. The light turns off
when fuel is added. If it does not,
have the vehicle serviced. Security Light The security light should come on
briefly as the engine is started. If it
does not come on, have the vehicle
serviced by your dealer. If the
system is working normally, the
indicator light turns off.
If the light stays on and the engine
does not start, there could be a
problem with the theft-deterrent
system. See Immobilizer Operation
0 55 .
High-Beam On Light

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 201Before Driving Off-Road .
Have all necessary maintenance
and service work completed.
.
Fuel the vehicle, fill fluid levels,
and check inflation pressure in
all tires, including the spare,
if equipped.
.
Read all the information about
four-wheel-drive vehicles in this
manual.
.
Remove any underbody air
deflector, if equipped. Re-attach
the air deflector after off-road
driving.
.
Know the local laws that apply to
off-road driving.
To gain more ground clearance if
needed, it may be necessary to
remove the front fascia lower air
dam, if equipped. However, driving
without the air dam reduces fuel
economy. CautionOperating the vehicle for
extended periods without the front
fascia lower air dam installed can
cause improper airflow to the
engine. Reattach the front fascia
air dam after off-road driving.
Loading the Vehicle for
Off-Road Driving
{ Warning.
Unsecured cargo on the
load floor can be tossed
about when driving over
rough terrain. You or your
passengers can be struck
by flying objects. Secure the
cargo properly.
.
Keep cargo in the cargo
area as far forward and as
low as possible. The
(Continued) Warning (Continued) heaviest things should be
on the floor, forward of the
rear axle.
.
Heavy loads on the roof
raise the vehicle's center of
gravity, making it more likely
to roll over. You can be
seriously or fatally injured if
the vehicle rolls over. Put
heavy loads inside the
cargo area, not on the roof.
For more information about loading
the vehicle, see Vehicle Load Limits
0 209 and Tires 0 358 .
Environmental Concerns .
Always use established trails,
roads, and areas that have been
set aside for public off-road
recreational driving and obey all
posted regulations.
.
Do not damage shrubs, flowers,
trees, or grasses or disturb
wildlife.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 205CautionDo not drive through standing
water if it is deep enough to cover
the wheel hubs, axles, or exhaust
pipe. Deep water can damage the
axle and other vehicle parts.
If the standing water is not too deep,
drive through it slowly. At faster
speeds, water can get into the
engine and cause it to stall. Stalling
can occur if the exhaust pipe is
under water. Do not turn off the
ignition when driving through water.
If the exhaust pipe is under water,
the engine will not start. When going
through water, the brakes get wet
and it may take longer to stop. See
“ Driving on Wet Roads ” later in this
section.
After Off-Road Driving
Remove any brush or debris that
has collected on the underbody or
chassis, or under the hood. These
accumulations can be a fire hazard.
Re-install underbody air deflector
and air dam if removed. After operation in mud or sand,
have the brake linings cleaned and
checked. These substances can
cause glazing and uneven braking.
Check the body structure, driveline,
steering, suspension, wheels, tires,
and exhaust system for damage and
check the fuel lines and cooling
system for any leakage.
More frequent maintenance service
is required. See the Maintenance
Schedule 0 415 .
Driving on Wet Roads Rain and wet roads can reduce
vehicle traction and affect your
ability to stop and accelerate.
Always drive slower in these types
of driving conditions and avoid
driving through large puddles and
deep-standing or flowing water. { WarningWet brakes can cause crashes.
They might not work as well in a
quick stop and could cause
pulling to one side. You could
lose control of the vehicle.
After driving through a large
puddle of water or a car/vehicle
wash, lightly apply the brake
pedal until the brakes work
normally.
Flowing or rushing water creates
strong forces. Driving through
flowing water could cause the
vehicle to be carried away. If this
happens, you and other vehicle
occupants could drown. Do not
ignore police warnings and be
very cautious about trying to drive
through flowing water.
Hydroplaning
Hydroplaning is dangerous. Water
can build up under the vehicle's
tires so they actually ride on the
water. This can happen if the road is

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
206 Driving and Operating wet enough and you are going fast
enough. When the vehicle is
hydroplaning, it has little or no
contact with the road.
There is no hard and fast rule about
hydroplaning. The best advice is to
slow down when the road is wet.
Other Rainy Weather Tips Besides slowing down, other wet
weather driving tips include:
.
Allow extra following distance.
.
Pass with caution.
.
Keep windshield wiping
equipment in good shape.
.
Keep the windshield washer fluid
reservoir filled.
.
Have good tires with proper
tread depth. See Tires 0 358 .
.
Turn off cruise control.
Hill and Mountain Roads Driving on steep hills or through
mountains is different than driving
on flat or rolling terrain. Tips include: .
Keep the vehicle serviced and in
good shape.
.
Check all fluid levels and brakes,
tires, cooling system, and
transmission.
.
Shift to a lower gear when going
down steep or long hills.
{ WarningUsing the brakes to slow the
vehicle on a long downhill slope
can cause brake overheating, can
reduce brake performance, and
could result in a loss of braking.
Shift the transmission to a lower
gear to let the engine assist the
brakes on a steep downhill slope.
{ Warning
Coasting downhill in N (Neutral)
or with the ignition off is
dangerous. This can cause
overheating of the brakes and
(Continued) Warning (Continued) loss of steering assist. Always
have the engine running and the
vehicle in gear.
.
Drive at speeds that keep the
vehicle in its own lane. Do not
swing wide or cross the
center line.
.
Be alert on top of hills;
something could be in your lane
(e.g., stalled car, crash).
.
Pay attention to special road
signs (e.g., falling rocks area,
winding roads, long grades,
passing or no-passing zones)
and take appropriate action.
Winter Driving Driving on Snow or Ice
Snow or ice between the tires and
the road creates less traction or
grip, so drive carefully. Wet ice can
occur at about 0 °C (32 °F) when

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 223.
The vehicle battery has recently
been disconnected.
.
Minimum vehicle speed has not
been reached since the last
Auto Stop.
.
The accelerator pedal is
pressed.
.
The engine or transmission is
not at the required operating
temperature.
.
The outside temperature is not
in the required operating range.
.
The vehicle is in any gear other
than D (Drive).
.
Tow/Haul Mode or other driver
modes have been selected.
.
The vehicle is on a steep hill or
grade.
.
The driver door has been
opened or the driver seat belt
has been unbuckled.
.
The hood has been opened.
.
The Auto Stop has reached the
maximum allowed time. Auto Stop Disable Switch
If equipped, the automatic engine
Stop/Start feature can be disabled
and enabled by pressing the switch
with the
h symbol. Auto Stop is
enabled each time you start the
vehicle.
When
h is illuminated, the system
is enabled.
Engine Heater The engine heater can provide
easier starting and better fuel
economy during engine warm-up in
cold weather conditions at or below − 18 °C (0 °F). Vehicles with an
engine heater should be plugged in
at least four hours before starting.
An internal thermostat in the
plug-end of the cord may exist,
which will prevent engine heater
operation at temperatures above
− 18 °C (0 °F).
{ WarningDo not plug in the engine block
heater while the vehicle is parked
in a garage or under a carport.
Property damage or personal
injury may result. Always park the
vehicle in a clear open area away
from buildings or structures.
To Use the Engine Heater 1. Turn off the engine.
2. Check the heater cord for
damage. If it is damaged, do
not use it. See your dealer for
a replacement. Inspect the
cord for damage yearly.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 241ABS is active, it may indicate that
road surfaces are slippery. Braking
sooner may be required for driving
conditions.
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.
Electric Parking Brake
The vehicle has an Electric Parking
Brake (EPB). The EPB can always
be activated, even if the ignition is off. To prevent draining the battery,
avoid repeated cycles of the EPB
when the engine is not running.
The system has a
Y or PARK
Electric Parking Brake light, and a
8Service Parking Brake light.
See Electric Parking Brake Light
0 152 and Service Electric Parking
Brake Light 0 152 . There are also
parking brake-related Driver
Information Center (DIC) messages.
Before leaving the vehicle, check for
the
Y or PARK light to ensure that
the parking brake is applied.
EPB Apply To apply the EPB:
1. Be sure the vehicle is at a
complete stop.
2. Press the EPB switch
momentarily.
The
Y or PARK light will flash and
then stay on once the EPB is fully
applied. If the
Y or PARK light
flashes continuously, then the EPB
is only partially applied or there is a problem with the EPB. A DIC
message will display. Release the
EPB and try to apply it again. If the
light does not come on, or keeps
flashing, have the vehicle serviced.
Do not drive the vehicle if the
Y or
PARK light is flashing. See your
dealer. See Electric Parking Brake
Light 0 152 .
If the
8 light is on, press the EPB
switch and hold it. Continue to hold
the switch until the
Y or PARK
light remains on. If the
8 light
remains on, see your dealer.
If the EPB is applied while the
vehicle is moving, the vehicle will
decelerate as long as the switch is
pressed. If the switch is pressed
until the vehicle comes to a stop,
the EPB will remain applied.
The vehicle may automatically apply
the EPB in some situations when
the vehicle is not moving. This is
normal, and is done to periodically
check the correct operation of the
EPB system.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 243This feature is designed to prevent
the vehicle from rolling, either
forward or rearward, during vehicle
drive off. HSA will be automatically
activated after the vehicle has come
to a complete standstill on a grade.
During the transition period between
when the brake pedal is released
and the accelerator pedal is
pressed, HSA holds the braking
pressure to ensure that there is no
rolling. The brakes will automatically
release when the accelerator pedal
is applied. It will not activate if the
vehicle is in a drive gear and facing
downhill, or if the vehicle is facing
uphill and in R (Reverse). Ride Control Systems Traction Control/
Electronic Stability
Control System Operation The vehicle has a Traction Control
System (TCS) and StabiliTrak/
Electronic Stability Control (ESC),
an electronic stability control
system. These systems help limit
wheel spin and assist the driver in
maintaining control, especially on
slippery road conditions.
TCS activates if it senses any of the
drive wheels are spinning or
beginning to lose traction. When this
happens, TCS applies the brakes to
the spinning wheels and reduces
engine power to limit wheel spin.
StabiliTrak/ESC activates when the
vehicle senses a difference between
the intended path and the direction
the vehicle is actually traveling.
StabiliTrak/ESC selectively applies
braking pressure to any one of the
vehicle wheel brakes to assist the driver in keeping the vehicle on the
intended path. Trailer Sway Control
(TSC) is also on automatically when
the vehicle is started. See Trailer
Sway Control (TSC) 0 293 .
If cruise control is being used and
traction control or StabiliTrak/ESC
begins to limit wheel spin, cruise
control will disengage. Cruise
control may be turned back on when
road conditions allow.
Both systems come on
automatically when the vehicle is
started and begins to move. The
systems may be heard or felt while
they are operating or while
performing diagnostic checks. This
is normal and does not mean there
is a problem with the vehicle.
It is recommended to leave both
systems on for normal driving
conditions, but it may be necessary
to turn TCS off if the vehicle gets
stuck in sand, mud, ice, or snow.
See If the Vehicle Is Stuck 0 208
and “ Turning the Systems Off and
On ” later in this section.

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 281the drive mode that is
appropriate for the road
conditions.
CautionIf the vehicle tires begin to spin
and the vehicle begins to slide
toward the water, remove your
foot from the accelerator pedal
and apply the brake pedal. Seek
help to have the vehicle towed up
the ramp.
Maintenance when Trailer
Towing The vehicle needs service more
often when used to tow trailers. See
Maintenance Schedule 0 415 . It is
especially important to check the
automatic transmission fluid, engine
oil, axle lubricant, belts, cooling
system, and brake system before
and during each trip.
Check periodically to see that all
nuts and bolts on the trailer hitch
are tight. Engine Cooling When Trailer
Towing The cooling system may temporarily
overheat during severe operating
conditions. See Engine Overheating
0 331 .
Trailer Towing If equipped with a diesel engine,
see the Duramax diesel
supplement.
CautionTowing a trailer improperly can
damage the vehicle and result in
costly repairs not covered by the
vehicle warranty. To tow a trailer
correctly, follow the directions in
this section and see your dealer
for important information about
towing a trailer with the vehicle.
Trailering is different than just
driving the vehicle by itself.
Trailering means changes in
handling, acceleration, braking,
durability, and fuel economy. Successful, safe trailering takes
correct equipment, and it has to be
used properly.
The following information has many
time-tested, important trailering tips
and safety rules. Many of these are
important for your safety and that of
your passengers. Read this section
carefully before pulling a trailer.
Trailer Weight
{ WarningNever exceed the towing capacity
for your vehicle.
Safe trailering requires monitoring
the weight, speed, altitude, road
grades, outside temperature, and
how frequently the vehicle is used to
tow a trailer.
Trailer Weight Ratings
When towing a trailer, the combined
weight of the vehicle, vehicle
contents, trailer, and trailer contents

GMC Sierra/Sierra Denali Owner Manual (GMNA-Localizing-U.S./Canada/
Mexico-1500-11698638) - 2019 - crc - 5/16/18
Driving and Operating 289Electric Brake Control Wiring
Provisions If the vehicle is not equipped with
an integrated trailer brake controller,
and the trailer has electric brakes, a
trailer brake controller needs to be
installed on the vehicle. The brake
controller should be installed by
your dealer or a qualified service
center.
If equipped, there is a trailer brake
jumper harness provided with the
vehicle. The connector on the trailer
brake jumper harness is attached to
a mating connector to the left of the
steering wheel behind the knee
bolster. The four blunt cut wires on
the jumper harness need to be
connected to an aftermarket electric
trailer brake controller. The harness
contains the following circuits:
Electric Trailer
Brakes Blue
Battery Feed Red/Violet or
Red/Black
Brake Apply
Signal White/Blue Ground Black
The fuse for the electric trailer brake
circuit is in the engine compartment
fuse block, but the wires may not be
connected. They should be
connected by your dealer or a
qualified service center.
Refer to the aftermarket electric
trailer brake controller owner's
manual to determine wire color
coding of the electric trailer brake
controller. The wire colors on the
brake controller may be different
from the vehicle.
Trailer Lamps Always check all trailer lamps are
working at the beginning of each
trip, and periodically on longer trips.
If equipped, the trailering app will
monitor the brake lamps, turn signal
lamps, running lamps and reverse
lamps on the trailer. DIC messages
may be displayed if lighting circuit
issues are detected on the trailer. The trailer bulbs can be observed
by starting the trailer light test
sequence. See Trailering App
0 296 .
Turn Signals When Towing a
Trailer When properly connected, the trailer
turn signals will illuminate to indicate
the vehicle is turning, changing
lanes, or stopping. When towing a
trailer, the arrows on the instrument
cluster will illuminate even if the
trailer is not properly connected or
the bulbs are burned out.
Tow/Haul Mode For instructions on how to enter
Tow/Haul Mode, see Driver Mode
Control 0 246 .
Tow/Haul assists when pulling a
heavy trailer or a large or heavy
load. See Tow/Haul Mode 0 234 .
Tow/Haul Mode is designed to be
most effective when the vehicle and
trailer combined weight is at least
75% of the vehicle's Gross