If your car is saying Shift to Park when it's already in park, there are a few possible explanations. First, it could be that the shift interlock solenoid is faulty and needs to be replaced. This solenoid prevents the shifter from being moved out of park unless the brake pedal is depressed, so if it's not working properly it could trigger the error message. Another possibility is that there's an issue with the shifter itself - sometimes debris can get lodged in the mechanism and prevent it from fully engaging in park. In this case, cleaning or replacing the shifter should fix the problem. Finally, it could be a problem with one of the sensors that tells the car what position the shifter is in. If this sensor isn't working properly, it could cause the Shift to Park message to appear even when the car is already in park. Replacing or resetting this sensor should solve the issue.