GMC 2009 Sierra 1500 Crew Cab Owner's Manual page 357

CAUTION:
{
Snow can trap engine exhaust under the vehicle.
This may cause exhaust gases to get inside.
Engine exhaust contains carbon monoxide (CO)
which cannot be seen or smelled. It can cause
unconsciousness and even death.
If the vehicle is stuck in the snow:
•
Clear away snow from around the base of
your vehicle, especially any that is blocking
the exhaust pipe.
•
Check again from time to time to be sure
snow does not collect there.
•
Open a window about two inches (5 cm) on
the side of the vehicle that is away from the
wind to bring in fresh air.
•
Fully open the air outlets on or under the
instrument panel.
•
Adjust the Climate Control system to a setting
that circulates the air inside the vehicle and
set the fan speed to the highest setting.
See Climate Control System in the Index.
CAUTION: (Continued)
CAUTION: (Continued)
For more information about carbon monoxide,
see Engine Exhaust on page 2-55.
Snow can trap exhaust gases under your vehicle.
This can cause deadly CO (carbon monoxide) gas
to get inside. CO could overcome you and kill you.
You cannot see it or smell it, so you might not know
it is in your vehicle. Clear away snow from around
the base of your vehicle, especially any that is
blocking the exhaust.
Run the engine for short periods only as needed to keep
warm, but be careful.
To save fuel, run the engine for only short periods as
needed to warm the vehicle and then shut the engine off
and close the window most of the way to save heat.
Repeat this until help arrives but only when you feel really
uncomfortable from the cold. Moving about to keep warm
also helps.
If it takes some time for help to arrive, now and then
when you run the engine, push the accelerator pedal
slightly so the engine runs faster than the idle speed. This
keeps the battery charged to restart the vehicle and to
signal for help with the headlamps. Do this as little as
possible to save fuel.
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