Cadillac 2011 STS Owner's Manual page 136

The length of time the heater should remain plugged in
depends on several factors. Ask a dealer in the area
where you will be parking the vehicle for the best advice
on this.
This position locks the rear wheels. It is the
best position to use when you start the engine because
the vehicle cannot move easily.
3-30
There are several
different positions for the
shift lever.
It is dangerous to get out of the vehicle if the shift
lever is not fully in P (Park) with the parking brake
firmly set. The vehicle can roll.
Do not leave the vehicle when the engine is
running unless you have to. If you have left the
engine running, the vehicle can move suddenly.
You or others could be injured. To be sure the
vehicle will not move, even when you are on fairly
level ground, always set the parking brake and
move the shift lever to P (Park). See Shifting Into
Park on page 3 34. If you are pulling a trailer,
see Towing a Trailer on page 5 31.
Make sure the shift lever is fully in P (Park) before
starting the engine. The vehicle has an automatic
transmission shift lock control system. You must fully
apply your regular brakes first and then press the shift
lever button before you can shift from P (Park) when the
vehicle is running. If you cannot shift out of P (Park),
ease pressure on the shift lever and push the shift
lever all the way into P (Park) as you maintain brake
application. Then press the shift lever button and move
the shift lever into another gear. See Shifting Out of
Park on page 3 35.