Shift Interlock: Description and Operation

A/T KEY INTERLOCK
Voltage is provided at all times through fuse 25 to the key interlock switch. When you push the key in, volt- age is provided to the key interlock solenoid, and the interlock control unit. You can then turn the key OFF, and remove it. However, if the Aft gear position switch is not in PARK, the interlock control unit will provide ground to the key interlock solenoid, energizing it so the key cannot be removed.

A/T GEAR LEVER INTERLOCK
With the ignition switch in RUN or START, voltage is provided to the shift lock solenoid through fuse 1. When the Aft gear position switch is in PARK, the transmission control module (TCM) provides voltage to the shift lock circuit, provided the brake pedal is pushed and the throttle is not. Ground is provided to the shift lock solenoid through the Aft gear position switch. The solenoid then energizes, releasing the Aft gear lever.