GMC Sierra Owners Manual
Automatic Transmission Shift Lock Control Function Check
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 9‑58.
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.