Steering Column Lock
WARNING: This page is about a different car, the 2002 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
The steering column lock is integral to the lock cylinder. When the ignition key is removed or turned to the LOCK position, a small key inside the steering column lock engages with the steering column tube, locking it into position. When the ignition key is turned to the OFF, START, or ON position, the steering column lock key withdraws, unlocking the steering column tube and allowing it to rotate.