Ignition Key Inhibit

The ignition key cylinder inhibit feature prevents the ignition lock cylinder from being rotated to the OFF position when the vehicle is not in PARK.

The key removal inhibit solenoid (part of the ignition switch) receives battery voltage at all times from the BCM  fuse 18 (5A). The ground circuit for the key removal inhibit solenoid is routed through a park detect switch within the selector lever assembly and then to the BCM  .

When the selector lever is in PARK, the park detect switch inside the selector lever assembly is open, preventing the solenoid from actuating. When the selector lever is moved out of PARK, the switch closes and completes the circuit to the BCM  . The BCM  controls the ground by means of a Field Effect Transistor (FET). The BCM  enables the path to ground when it detects the vehicle is not in PARK based on messages received over the CAN. 

When the selector lever is in PARK, the key removal inhibit solenoid deactivates and allows the ignition lock cylinder to be turned to the OFF position and the key to be removed.