So, the rear sensors on 2006 Mazda 2 were playing up one day. A friend disconnected the car battery (with parking lights still on - not sure if this has anything to do with it) to reset sensors and then they reconnected the battery after a few minutes. Now anti-theft has been activated and car won't start/crank. I am able to push start car pretty easily and still drive around no problem. I only have 1 key and no key fob. Immobilizer light in dash is flashing continuously even while driving or when car is turned off & locked. I only have 1 key and no key fob. I have tried replacing with new battery but still same. How do I fix this problem? Is it an electrical issue or is it a key issue? The key works fine because I can stil drive car after push starting it and all the electricals work it just wont crank with key. Please any ideas or advice? Praying that it wont be too expensive to fix.