GMC Canyon Owner's Manual page 133

Leaving Your Vehicle With the Engine
Running (Automatic Transmission)
CAUTION:
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It can be dangerous to leave your vehicle
with the engine running. Your vehicle
could move suddenly if the shift lever is
not fully in PARK (P) with the parking
brake firmly set. And, if you leave the
vehicle with the engine running, it could
overheat and even catch fire. You or
others could be injured. Do not leave
your vehicle with the engine running.
If you have to leave your vehicle with the engine
running, be sure your vehicle is in PARK (P)
and your parking brake is firmly set before you
leave it. After you have moved the shift lever into
PARK (P), hold the regular brake pedal down.
Then, see if you can move the shift lever
away from PARK (P) without first pulling it toward
you. If you can, it means that the shift lever
was not fully locked into PARK (P).
Torque Lock (Automatic Transmission)
If you are parking on a hill and you do not shift
your transmission into PARK (P) properly,
the weight of the vehicle may put too much force
on the parking pawl in the transmission. You
may find it difficult to pull the shift lever out
of PARK (P). This is called torque lock. To prevent
torque lock, set the parking brake and then shift
into PARK (P) properly before you leave the
driver's seat. To find out how, see Shifting Into
Park (P) (Automatic Transmission) on page 132.
When you are ready to drive, move the shift
lever out of PARK (P) before you release the
parking brake.
If torque lock does occur, you may need to
have another vehicle push yours a little uphill to
take some of the pressure from the parking pawl
in the transmission, so you can pull the shift
lever out of PARK (P).
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