How do I reset the theft system?

Here is a guide that will help with the common ways to disarm it:

https://www.2carpros.com/articles/how-to-reset-a-security-system

If this doesn't work then we will most likely need to scan for codes to see if there are any there and that will tell us what the issue is. Also, have you tried another key? If not, let's do these two things in addition to the guide above and go from there.

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

Hi,

There is no reset. However, try this. Turn the key to the run position and allow it to sit for approximately 10 minutes. The theft light should turn off and the car should start. Try that and let me know if it works.

If it does or doesn't, we need to retrieve diagnostic trouble codes to see where the problem is coming from. I don't know if you have the original key, if there is a problem with one of the components or what is happening at this point. You may end up having to scan the can bus system to see if anything shows up. Here is a video showing how that is done:

https://youtu.be/InIlnsjOVFA

Let me know and we'll figure it out together.

Joe