2001 GMC Sierra 1500 Pickup Owner's Manual - Page 102

LOCK (B): This position locks your ignition and transmission. It's a theft-deterrent feature. You will only be able to remove your key when the ignition is turned to LOCK. NOTICE: If your key seems stuck in LOCK and you can't turn it, be sure you are using the correct key; if so, is it all the way in? Turn the key only with your hand. Using a tool to force it could break the key or the ignition switch. If none of this works, then your vehicle needs service. OFF (C): This position lets you turn off the engine. Use OFF if you must have your vehicle in motion while the engine is off (for example, if your vehicle is being pushed). RUN (D): This is the position for driving. START (E): This position starts your engine. CAUTION: On manual transmission vehicles, turning the key to LOCK will lock the steering column and result in a loss of ability to steer the vehicle. This could cause a collision. If you need to turn the engine off while the vehicle is moving, turn the key only to OFF. Don't press the key release button while the vehicle is moving. 2-19