Security Light
 

Howdy, I got a 2006 Milan for free from a family member, it’s been sitting about a year. We slapped a new battery in it, lights came on, but the car will not crank. The red security light is flashing (I believe it’s the PATS light) yesterday after just playing around with it for about 3 hours, I was able to start the car. Shut it off, started back up fine again, tried starting it today, and same security light is back. The key unlocks/locks the doors, and was able to start it yesterday. What can cause this? What’s the best way to fix it or bypass the PATS system