Immobilizer light on

There are a couple things we can try. Worst case scenario you will need to scan for codes and see what is there as you may have hurt some modules or fuses.

First put the key in the ignition and turn it to the on position and let it sit for 30 minutes. Clearly turn off all the lights and radio and HVAC so it doesn't drain the battery too much. After 10 minutes check and see if the theft light is off. Then check every 10 minutes up to 30 minutes. Once the light goes off, you should be good to go.

If that doesn't work, here is a guide that gives a couple more items:

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

Last resort, we need to have it scanned for codes and see what is there. Let me know if you have questions and we can go from there. Thanks

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