When you changed the Fob battery, did you use a new, out of the packet battery (CR1632 if I remember right). I had sort of similar issues and tested my batteries 3 times--always tested good. One of my 2 testers was supposedly NIST traceable, meaning it was supposed to be a good tester. I bought new batteries, replaced one in the Fob, and the problem was solved. For $5, I'd suggest you again replace the batteries.i changed tha key battery but without result. when i am pressing power button for about 15 seconds the car is starting. from where to start find a problem?