Ignition Key Inhibit

WARNING: This page is about a different car, the 2020 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

The ignition key cylinder inhibit feature prevents the ignition lock cylinder from being rotated to the OFF/LOCK 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 control circuit for the key removal inhibit solenoid is routed to a park detect switch within the selector lever assembly (floor shift) or the brake shift interlock actuator (column shift).

For vehicles equipped with a floor shifter, the ground is controlled by the BCM.

For vehicles equipped with a column shifter, the park detect switch routes the signal directly to ground to activate the ignition key inhibit solenoid.

When the selector lever is in PARK, the park detect switch inside the selector lever assembly (floor shift) or the brake shift interlock actuator (column shift) 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 (floor shifter) or to ground (column shift).

For vehicles with a floor shifter, 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/LOCK position to remove the key.