Using a replacement key, how do get it out of theft mode?

Can you give a little more detail about what type of key you are using? Did you program this key? If the key is not programmed then the theft light will not shut off.

Your vehicle has what is called a SKIM key which means that key is programmed to the vehicle so that when you insert it and sends a signal to the modules and it has the correct code and the PCM is able to start the vehicle.

Attached below is the process to program a key for your review.

Let us know what questions you have. Thanks

I understand the key can turn the cylinder to start the vehicle but has it been programmed? If it is then we need to check the codes and find out why the theft light is staying on.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

I attached the process to a prior response but put it below again. You need to have other keys that are already programmed in order to enter into "customer programming mode." If you do not have other keys then you need a dealer or shop with the ability to program the key.