2002 Ford Explorer won't start

I hope you got it fix I had the same problem. And yes is the alarm the key is not sending the signal to the transmitter is not expensive and your old key will work.They just need to program it again, make sure they change that antenna or transmitter if not is going to happen again. You won’t be able to turn your truck on you can see the red flashing light on top when it won’t turn on that means the alarm is on. Good luck

Take the battery connectors off battery. Hold the positive and negative connectors together for a minute or so. Place the connectors back on battery and attempt starting the vehicle. This action basically reboots the vehicle on board computer and should allow the system to communicate with each other correctly.