When I turn my car off it won't stop beeping. It say its not in park.

Hello, There are four things that can cause this issue: 1. The shift cable is out of adjustment, so the switch on the gear selector does not read that the shift lever has been moved to the park position. 2. The transmission has a mode switch that signals the body control module that it is in park. That and the gear selector must agree on position or you get the warning message specified in your question. 3. The body control module could be faulty, and misreading the signal from the transmission mode switch. 4. The switch on the gear selector (shift lever) is faulty, and the entire shift lever assembly may need to be replaced as a unit. The switch may not be available by itself. Unfortunately, diagnosis of this issue in all cases will require a trained technician, and in three of the four cases, a professional scan tool. Ensure a certified shop with the proper equipment handles this repair.