Information - GMC 2012 Sierra Denali Owner's Manual

This position can be
used to operate the electrical
accessories and to display some
instrument panel 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 on automatic transmission
vehicles.
If you leave the key in the ACC/
ACCESSORY or ON/RUN position
with the engine off, the battery could
be drained. You may not be able to
start the vehicle if the battery is
allowed to drain for an extended
period of time.
This is the position that
starts the engine. When the engine
starts, release the key. The ignition
switch returns to ON/RUN for
driving.
A warning tone will sound when the
driver door is opened and the
ignition is in ACC/ACCESSORY or
LOCK/OFF, and the key is in the
ignition.
If the vehicle has the DURAMAX
Diesel engine, see the DURAMAX
Diesel supplement for more

information.

Move the shift lever to P (Park) or
N (Neutral). The engine will not start
in any other position. To restart the
engine when the vehicle is already
moving, use N (Neutral) only.
1. With your foot off the accelerator
pedal, turn the ignition to START.
When the engine starts, let go of
the key. The idle speed will slow
down as the engine warms. 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.
The vehicle has a
®
Computer-Controlled Cranking
®
System. This feature assists in
starting the engine and protects
components. If the ignition key is
turned to the START position,
and then released when the
engine begins cranking, the
engine will continue cranking for
a few seconds or until the
vehicle starts. If the engine does
not start and the key is held in
START, cranking will be stopped
after 15 seconds to prevent
cranking motor damage. To
prevent gear damage, this
system also prevents cranking if