Park Lock System Description
WARNING: This page is about a different car, the 2004 Pontiac Vibe. However, it is still accessible from the selected car via links, so may be relevant.
The park lock system prevents ignition lock cylinder movement to the LOCK position when the automatic transmission (A/T) shift lever is in any position other than Park. A cable is attached to the A/T shift lever and to the ignition switch cylinder case. Moving the A/T shift lever out of the Park position pulls the cable and prevents the cylinder from moving to the LOCK position. Moving the A/T shift lever to the PARK position pushes the cable and allows the cylinder to move to the LOCK position.