GMC Express 2011 Owner's Manual page 305

Automatic Transmission
Shift Lock Control
Function Check
WARNING
When you are doing this
inspection, the vehicle could
move suddenly. If the vehicle
moves, you or others could
be injured.
1. Before starting this check,
be sure there is enough room
around the vehicle. It should be
parked on a level surface.
2. Firmly apply the parking brake.
See Parking Brake on
page 9 34.
Be ready to apply the regular
brake immediately if the vehicle
begins to move.
3. With the engine off, turn the
ignition on, but do not start the
engine. Without applying the
regular brake, try to move the
shift lever out of P (Park) with
normal effort. If the shift lever
moves out of P (Park), contact
your dealer for service.
Vehicle Care
Ignition Transmission
Lock Check
While parked, and with the
parking brake set, try to turn the
ignition to LOCK/OFF in each shift
lever position.
The ignition should turn to
LOCK/OFF only when the shift
lever is in P (Park).
The ignition key should come
out only in LOCK/OFF.
Contact your dealer if service is
required.
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