stop start GMC SIERRA 2023 Owner's Manual

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 223
Caution
Use the correct key, make sure it is all
the way in—or pushed all the way in
toward the steering column when turning
off the vehicle —and turn it only with
your hand.
1 (ACC/ACCESSORY) : This position allows
features such as the infotainment system to
operate while the vehicle is off. It also
unlocks the steering column, if equipped
with a locking steering column. Use this
position if the vehicle must be pushed or
towed. See Retained Accessory Power (RAP)
0 227.
From ON/RUN, push the key all the way in
toward the steering column, then turn the
key to ACC/ACCESSORY.
If the key is left in ACC/ACCESSORY with the
engine off, the battery could drain and the
vehicle may not start.
A warning chime will sound when the driver
door is opened and the key is in the
ignition.
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.
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 ON/RUN with the engine
off, the battery could drain and the vehicle
may not start.
3 (START) :
This is the position that starts
the engine. When the engine starts, release
the key. The ignition returns to ON/RUN for
driving.
Ignition Positions (Keyless Access)
Vehicles equipped with Keyless Access have
pushbutton starting.
The remote key must be in the vehicle for
the system to operate. If the pushbutton
start is not working, the vehicle may be
near a strong radio antenna signal causing
interference to the Keyless Access system.
See Remote Keyless Entry (RKE) System
Operation (Key Access) 012 or
Remote Keyless Entry (RKE) System
Operation (Keyless Access) 014.
To shift out of P (Park), the ignition must be
on or in Service Mode, and the brake pedal
must be applied.
{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.
Stopping the Engine/LOCK/OFF (No Indicator
Lights) : When the vehicle is stopped, press
ENGINE START/STOP once to turn the
engine off.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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224 Driving and Operating
If the vehicle is in P (Park), the ignition will
turn off, and Retained Accessory Power (RAP)
will remain active. SeeRetained Accessory
Power (RAP) 0227.
If the vehicle is not in P (Park), the ignition
will return to accessory mode and display
the message SHIFT TO PARK in the Driver
Information Center (DIC). When the vehicle is
shifted into P (Park), the ignition system will
turn off.
The vehicle may have an electric steering
column lock. The lock is activated when the
ignition is turned off and driver door is
opened. A sound may be heard as the lock
actuates or releases. The steering column
lock may not release with the wheels turned
off center. If this happens, the vehicle may
not start. Move the steering wheel from left
to right while attempting to start the
vehicle. If this does not work, the vehicle
needs service.
Unless an emergency exists, do not turn the
engine off when the vehicle is moving. This
will 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. If the vehicle cannot be pulled over, and
must be shut off while driving, press and
hold ENGINE START/STOP button for
longer than two seconds, or press twice
in five seconds.
2. Brake using a firm and steady pressure. Do not pump the brakes repeatedly. This
may deplete power assist, requiring
increased brake pedal force.
3. 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.
4. Come to a complete stop, shift to P (Park), and make sure engine is off.
The shift lever must be in P (Park) to
turn the ignition off.
5. Set the parking brake. See Electric
Parking Brake 0239.
{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. Accessory Mode (Amber Indicator Light) :
This mode allows some electrical accessories
to be used when the engine is off.
With the ignition off, pressing the button
once without the brake pedal applied will
place the ignition system in accessory mode.
The ignition will switch from accessory
mode to OFF after five minutes to prevent
battery rundown.
ON/RUN/START (Green Indicator Light) :
This
mode is for driving and starting. With the
ignition off, and the brake pedal applied,
pressing ENGINE START/STOP button once
will turn the ignition on. Once engine
cranking begins, release the button. Engine
cranking will continue until the engine
starts. See Starting the Engine 0225.
Service Mode
This power mode is available for service and
diagnostics, and to verify the proper
operation of the malfunction indicator lamp
as may be required for emission inspection
purposes. With the vehicle off, and the
brake pedal not applied, pressing and
holding the ENGINE START/STOP button for
more than five seconds will place the vehicle
in Service Mode. The instruments and audio
systems will operate as they do when the

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
Driving and Operating 225
ignition is on, but the vehicle will not
be able to be driven. The engine will not
start in Service Mode. Press the ENGINE
START/STOP button again to turn the
ignition off.
Starting the Engine
If the vehicle has a diesel engine, see the
Duramax diesel 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.
SeeAdd-On Electrical Equipment 0297.
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. For Key Access vehicles, turn the ignition key to Start. When the engine starts, let
go of the key. For Keyless Access
vehicles, the remote key must be in the
vehicle. Press ENGINE START/STOP with
the brake pedal applied. When the
engine begins cranking, let go of the
button.
The driver may observe a minor, and
temporary, brake pedal kickback when
starting the vehicle. This is normal.
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.Caution
Cranking the engine for long periods of
time, by returning the ignition to the
START position immediately after
cranking has ended, can overheat and
damage the cranking motor, and drain
the battery. Wait at least 15 seconds
between each try, to let the cranking
motor cool down.
2. If the engine does not start after five to 10 seconds, especially in very cold
weather (below −18 °C or 0 °F), it could
be flooded with too much gasoline. Try
pushing the accelerator pedal all the way
to the floor and holding it there while
holding the key in START or ENGINE
START/STOP for up to a maximum of
15 seconds. Wait at least 15 seconds
between each try, to allow the cranking
motor to cool down. When the engine
starts, let go of the key or button and
accelerator. If the vehicle starts briefly
but then stops again, do the same thing.
This clears the extra gasoline from the
engine. Do not race the engine
immediately after starting it. Operate

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Driving and Operating 231
R :Use this gear to back up.
Caution
Shifting to R (Reverse) while the vehicle is
moving forward could damage the
transmission. The repairs would not be
covered by the vehicle warranty. Shift to
R (Reverse) only after the vehicle is
stopped.
To rock the vehicle back and forth to get
out of snow, ice, or sand without damaging
the transmission, see If the Vehicle Is Stuck
0 214.
N : In this position, the engine does not
connect with the wheels. To restart the
engine when the vehicle is already moving,
use N (Neutral) only.
Also, use N (Neutral) when the vehicle is
being towed.
{Warning
Shifting into a drive gear while the
engine is running at high speed is
dangerous. Unless your foot is firmly on
the brake pedal, the vehicle could move
very rapidly. You could lose control and
hit people or objects. Do not shift into a
drive gear while the engine is running at
high speed.
Caution
Shifting out of P (Park) or N (Neutral) with
the engine running at high speed may
damage the transmission. The repairs
would not be covered by the vehicle
warranty. Be sure the engine is not
running at high speed when shifting the
vehicle.
Caution
A transmission hot message may display
if the automatic transmission fluid is too
hot. Driving under this condition can
damage the vehicle. Stop and idle the
engine to cool the automatic
transmission fluid. This message clears
when the transmission fluid has cooled
sufficiently.
D : This position is for normal driving.
It provides the best fuel economy. If more
power is needed for passing, press the
accelerator pedal down.
.When going less than about 55 km/h
(35 mph), push the accelerator pedal
about halfway down.
.When going about 55 km/h (35 mph) or
more, push the accelerator all the
way down.
By doing this, the vehicle shifts down to
the next gear and has more power.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
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Driving and Operating 237
With the vehicle moving less than
5 km/h (3 mph) and the transmission in
N (Neutral), attempt the shift again.
Shifting Out of 4
n
1. The vehicle must be stopped or movingless than 5 km/h (3 mph) with the
transmission in N (Neutral) and the
ignition on. It is best for the vehicle to
be moving 1.6 to 3.2 km/h (1 to 2 mph).
2. Press 4
m, AUTO, or 2m. The actual 4x4
shift request is only made after the
button is released. The 4x4 graphic will
remain flashing until the shift request
has completed. A DIC message displays
to indicate the state of the request.
Once the 4x4 shift has completed, the
DIC message disappears, the 4x4 graphic
stops flashing, and the current setting is
indicated.
If vehicle speed is higher when shift
request occurs, a DIC message displays.
Reduce vehicle speed.
If the transmission is not in N (Neutral)
when shift request occurs, DIC messages will
display. The vehicle will allow 20 seconds for
this shift to occur. After this time, a graphic
in the instrument cluster will indicate that
the transfer case is in 4
n.
Caution
Shifting the transmission into gear before
the requested mode indicator light has
stopped flashing could damage the
transfer case.
If the transmission is not shifted into
N (Neutral) or the vehicle has not slowed to
5 km/h (3 mph) within 20 seconds, the
transfer case will remain in its original state.
This will be indicated in the instrument
cluster.
With the vehicle moving less than 5 km/h
(3 mph), and the transmission in N (Neutral),
attempt the shift again.
Shifting Into N (Neutral)
To shift into N (Neutral): 1. Start the vehicle.
2. Shift the transmission to N (Neutral).
3. Shift the transfer case to 2
m.
4. Apply the parking brake and/or brake pedal.
5. Press 2
mfive times in 10 seconds until
the N (Neutral) graphic starts flashing in
the instrument cluster. When the shift is
complete, the graphic stops flashing. If the parking brake and/or brake pedal
is not applied within 20 seconds, the
transfer case will remain in the original
state.
6. If the transmission is not shifted into N (Neutral) or the vehicle has not slowed
to 5 km/h (3 mph) within 20 seconds,
the transfer case will remain in its
original state. This will be indicated in
the instrument cluster.
Shifting Out of N (Neutral)
To shift out of N (Neutral): 1. Turn the ignition on with the engine off. See Ignition Positions (Key Access) 0221
or
Ignition Positions (Keyless Access) 0223.
2. Set the parking brake. See Electric
Parking Brake 0239.
3. Shift the transmission to N (Neutral).
4. Shift the transfer case to 2
m. Transfer
case shifts out of N (Neutral) can only be
made into 2
m. When the shift to 2mis
complete, the graphic in the instrument
cluster will stop flashing. If the transfer
case cannot complete a shift, the graphic
will return to the previously selected
setting.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
240 Driving and Operating
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, or at the request of other
safety functions that utilize the EPB.
If the EPB fails to apply, block the rear
wheels to prevent vehicle movement.
EPB Release
To release the EPB:1. Turn the ignition on or to ACC/ACCESSORY.
2. Apply and hold the brake pedal.
3. Press the EPB switch momentarily.
The EPB is released when the red parking
brake status light is off.
If the amber service parking brake warning
light is on, release the EPB by pressing and
holding the EPB switch. Continue to hold the
switch until the red parking brake status
light is off. If either light stays on after
release is attempted, see your dealer.
Caution
Driving with the parking brake on can
overheat the brake system and cause
premature wear or damage to brake
system parts. Make sure that the parking
brake is fully released and the brake
warning light is off before driving.
If you are towing a trailer and parking on a
hill, see Driving Characteristics and Towing
Tips 0268.
Automatic EPB Release
The EPB will automatically release if the
vehicle is running, placed into gear, and an
attempt is made to drive away. Avoid rapid
acceleration when the EPB is applied, to
preserve parking brake lining life.
Brake Assist
Brake Assist detects rapid brake pedal
applications due to emergency braking
situations and provides additional braking to
activate the Antilock Brake System (ABS) if
the brake pedal is not pushed hard enough
to activate ABS normally. Minor noise, brake
pedal pulsation, and/or pedal movement
during this time may occur. Continue to apply the brake pedal as the driving
situation dictates. Brake Assist disengages
when the brake pedal is released.
Hill Start Assist (HSA)
{Warning
Do not rely on the HSA feature. HSA does
not replace the need to pay attention
and drive safely. You may not hear or
feel alerts or warnings provided by this
system. Failure to use proper care when
driving may result in injury, death,
or vehicle damage. See
Defensive Driving
0 205.
When the vehicle is stopped on a grade, Hill
Start Assist (HSA) prevents the vehicle from
rolling in an unintended direction during the
transition from brake pedal release to
accelerator pedal apply. The brakes release
when the accelerator pedal is applied. If the
accelerator pedal is not applied within a few
minutes, the Electric Parking Brake will
apply. The brakes may also release under
other conditions. Do not rely on HSA to hold
the vehicle.

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Driving and Operating 241
HSA is available when the vehicle is facing
uphill in a forward gear, or when facing
downhill in R (Reverse). The vehicle must
come to a complete stop on a grade for HSA
to activate.
Ride Control Systems
Traction Control/Electronic
Stability Control
System Operation
The vehicle has a Traction Control System
(TCS) and StabiliTrak/Electronic Stability
Control (ESC) 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 keepingthe vehicle on the intended path. Trailer
Sway Control (TSC) is also on automatically
when the vehicle is started. See
Trailer Sway
Control (TSC) 0285.
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 0214 and “Turning the
Systems Off and On” later in this section.
When the transfer case (if equipped) is in
Four-Wheel Drive Low, the stability system
is automatically disabled,
gcomes on, and
the appropriate message will appear on the Driver Information Center (DIC). Both
traction control and StabiliTrak/ESC are
automatically disabled in this condition.
The indicator light for both systems is in the
instrument cluster. This light will:
.Flash when TCS is limiting wheel spin.
.Flash when StabiliTrak/ESC is activated.
.Turn on and stay on when either system
is not working.
If either system fails to turn on or to
activate, a message displays in the Driver
Information Center (DIC), and
dcomes on
and stays on to indicate that the system is
inactive and is not assisting the driver in
maintaining control. The vehicle is safe to
drive, but driving should be adjusted
accordingly.
If
dcomes on and stays on:
1. Stop the vehicle.
2. Turn the engine off and wait 15 seconds.
3. Start the engine.

GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16504257) - 2023 - CRC - 5/9/22
242 Driving and Operating
Drive the vehicle. Ifdcomes on and stays
on, the vehicle may need more time to
diagnose the problem. If the condition
persists, see your dealer.
Turning the Systems Off and On
The button for TCS and StabiliTrak/ESC is on
the center stack.
Caution
Do not repeatedly brake or accelerate
heavily when TCS is off. The vehicle
driveline could be damaged.
To turn off only TCS, press and release
g.
The traction off light
idisplays in the
instrument cluster. The appropriate message
will display in the DIC. To turn TCS on again,
press and release
g. The traction off light
idisplayed in the instrument cluster will
turn off. If TCS is limiting wheel spin when
gis
pressed, the system will not turn off until
the wheels stop spinning.
To turn off both TCS and StabiliTrak/ESC,
press and hold
guntil the traction off light
iand the StabiliTrak/ESC OFF lightgcome on and stay on in the instrument
cluster, then release. The appropriate
message will display in the DIC.
To turn TCS and StabiliTrak/ESC on again,
press and release
g. The traction off light
iand the StabiliTrak/ESC OFF lightgin
the instrument cluster turn off.
StabiliTrak/ESC will automatically turn on if
the vehicle exceeds 56 km/h (35 mph).
Traction control will remain off.
The vehicle has a Trailer Sway Control (TSC)
feature and a Hill Start Assist (HSA) feature.
See Trailer Sway Control (TSC) 0285 or
Hill Start Assist (HSA) 0240.
Adding accessories can affect the vehicle
performance. See Accessories and
Modifications 0302.
Hill Descent Control (HDC)
If equipped, Hill Descent Control (HDC) sets
and maintains vehicle speed while driving
down steep grades in a forward or reverse
gear. The HDC switch is on the center stack.
Press
5to enable or disable HDC. Vehicle
speed must be below 50 km/h (31 mph).
When enabled, the HDC light displays on
the instrument cluster.
A blinking HDC light indicates the system is
actively applying the brakes to maintain
vehicle speed. HDC can maintain vehicle
speeds between 1 and 22 km/h (1 and
14 mph) on grades greater than or equal
to 10%.
If HDC is to be used for more than
three minutes or on grades steeper than
25%, the transfer case should be put into
Four-Wheel Drive Low (4
n) to reduce the
possibility of brake overheating.

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Driving and Operating 265
The starting characteristics of E85 or FlexFuel
make it unsuitable for use when
temperatures fall below−18 °C (0 °F). Use
gasoline or add gasoline to the E85 or
FlexFuel.
Because E85 or FlexFuel has less energy per
liter (gallon) than gasoline, the vehicle will
need to be refilled more often. See Filling
the Tank (Chassis Cab and Box Delete
Models) 0266 or
Filling the Tank (Pickup Models) 0265.
The only GM approved aftermarket additive
is ACDelco Fuel System Treatment
Plus-FlexFuel. Follow the instructions on the
bottle for proper use. This product is
available at your GM dealer.
Caution
Some additives are not compatible with
E85 or FlexFuel and can harm the
vehicle's fuel system. Use only additives
approved by GM for E85 or FlexFuel
vehicles. Damage caused by unapproved
additives would not be covered by the
vehicle warranty.
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.
To help keep the engine running efficiently,
fill the tank with gasoline, up to E15, after
filling the tank with E85 one or two times.
Filling the Tank (Pickup Models)
If the vehicle has a diesel engine, see the
Duramax diesel supplement.
An arrow on the fuel gauge indicates which
side of the vehicle the fuel door is on. See
Fuel Gauge 0115.
{Warning
Fuel vapors and fuel fires burn violently
and can cause injury or death.
Follow these guidelines to help avoid
injuries to you and others:
.Read and follow all the instructions on
the fuel pump island.
.Turn off the engine when refueling.
(Continued)
Warning (Continued)
.Keep sparks, flames, and smoking
materials away from fuel.
.Do not leave the fuel pump
unattended.
.Avoid using electronic devices while
refueling.
.Do not re-enter the vehicle while
pumping fuel.
.Keep children away from the fuel
pump and never let children
pump fuel.
.Before touching the fill nozzle, touch a
metallic object to discharge static
electricity from your body.
.Fuel can spray out if the fill nozzle is
inserted too quickly. This spray can
happen if the tank is nearly full, and is
more likely in hot weather. Insert the
fill nozzle slowly and wait for any hiss
noise to stop before beginning to
flow fuel.

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Driving and Operating 267
{Warning
Fuel vapors and fuel fires burn violently
and can cause injury or death.
Follow these guidelines to help avoid
injuries to you and others:
.Read and follow all the instructions on
the fuel pump island.
.Turn off the engine when refueling.
.Keep sparks, flames, and smoking
materials away from fuel.
.Do not leave the fuel pump
unattended.
.Avoid using electronic devices while
refueling.
.Do not re-enter the vehicle while
pumping fuel.
.Keep children away from the fuel
pump and never let children
pump fuel.
.Before touching the fill nozzle, touch a
metallic object to discharge static
electricity from your body.(Continued)
Warning (Continued)
.Fuel can spray out if the fuel cap is
opened too quickly. This spray can
happen if the tank is nearly full, and is
more likely in hot weather. Open the
fuel cap slowly and wait for any hiss
noise to stop, then unscrew the cap all
the way.
Turn the fuel cap counterclockwise to
remove. Fully insert and latch the fill nozzle,
begin fueling. For models with dual fuel
tanks, the fuel gauge shows an average of
both tanks. When refueling, refuel the
primary front tank first, then add fuel to the
auxiliary rear tank.
{Warning
Overfilling the fuel tank by more than
three clicks of a standard fill nozzle may
cause:
.Vehicle performance issues, including
engine stalling and damage to the fuel
system.
.Fuel spills.
.Under certain conditions, fuel fires. Be careful not to spill fuel. Wait five seconds
after you have finished pumping before
removing the fill nozzle. Clean fuel from
painted surfaces as soon as possible. See
Exterior Care
0374. Reinstall the cap by
turning it clockwise until it clicks.
{Warning
If a fire starts while you are refueling, do
not remove the fill nozzle. Shut off the
flow of fuel by shutting off the pump or
by notifying the station attendant. Leave
the area immediately.
Caution
If a new fuel cap is needed, get the right
type of cap from your dealer. The wrong
type of fuel cap may not fit properly,
may turn on the malfunction indicator
lamp, and could damage the fuel system
and emissions system. See Malfunction
Indicator Lamp (Check Engine Light)
0 120.