GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
216 Driving and Operating
See“Certification/Tire Label” under
Vehicle Load Limits 0210. If weight
ratings are exceeded, move or remove
items to bring all weights below the
ratings.
See your dealer for more information
on curb weights, cargo weights, Cargo
Weight Rating, and the correct center of
gravity zone.
Starting and Operating
New Vehicle Break-In
Caution
During the first 800 km (500 mi) of
driving this vehicle, overall performance
will benefit by following these break-in
period recommendations:
.Avoid full throttle starts and abrupt
stops.
(Continued)
Caution (Continued)
.Avoid exceeding the following engine
speeds when accelerating or
downshifting to slow or brake the
vehicle:
Gasoline engines: 4000 rpm
Diesel engines: 3000 rpm
.Avoid making hard stops for the first
300 km (200 mi). Hard stops with new
brake linings can result in premature
wear and earlier replacement. Follow
this guideline every time brake linings
are replaced.
.Do not tow a trailer. See Trailer
Towing 0280 for the trailer towing
capabilities of the vehicle and more
information.
After the break-in period, the engine
speed and load can be gradually
increased.
On new vehicles, the various mechanical and
electrical systems adjust during the first
6,400 km (4,000 miles) of routine driving to
provide optimal fuel economy and
transmission shift performance. Electrical systems will adapt and calibrate
during the break-in period. A one-time
occurrence of clicks and similar vehicle
noises is normal during this process.
Normal driving charges the vehicle battery
to achieve the best operation of the vehicle.
Ignition Positions
Base Model Shown, Others Similar
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
GMC Sierra/Sierra Denali 2500 HD/3500 HD Owner Manual (GMNA-
Localizing-U.S./Canada-16908340) - 2024 - CRC - 12/13/22
Driving and Operating 217
near a strong radio antenna signal causing
interference to the Keyless Access system.
SeeRemote Key Operation 015.
To shift out of P (Park), the vehicle must be
on 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.
If the vehicle is in P (Park), the vehicle will
turn off, and Retained Accessory Power (RAP)
will remain active. See Retained Accessory
Power (RAP) 0220.
If the vehicle is not in P (Park), the vehicle
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 vehicle 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 vehicle off.
5. Set the parking brake. See Electric
Parking Brake 0234.
{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 vehicle off, pressing the ENGINE
START/STOP button one time without the
brake pedal applied will place the vehicle in
accessory mode.
