Most modern vehicles have a transponder key. This type of key contains a chip that is programmed to your specific car, so the car won't start unless the transponder chip is in the vehicle. In some cars you may not have a physical key at all, instead there is only the chipped remote that you use to unlock the car and the start button that you push when in the car with the chip on your person. If the transponder fails, not only can you not start your car, you also may not be able to get into it. The following troubleshooting tips can help you deal with this issue.
Tip #1: Look for a mechanical key
Many transponder remotes actually have a physical key hidden inside, even if one isn't readily visible. Check the remote for any small buttons or switches. If you find one, push or slide it to release the key. While this won't start the car, it will at least allow you to open the doors.
Tip #2: Check the battery
Your transponder key fob operates off battery power. Most car makes are programmed to let you know in some manner when the battery is dying, whether it's a dash light alert or some sort of indicator on the key itself. Still, it is possible to overlook this warning and end up with a dead battery. Fortunately, you can usually open the transponder and replace the battery yourself or you can have a locksmith do it for you.
Tip #3: Don't double up
Sometimes the issue is interference. Transponders from another vehicle or even the spare key to the same vehicle may interfere with the signal your car is reading, resulting in it refusing to start. Remove all keys from inside the vehicle except for the correct transponder to see if that resolves the problem.
Tip #4: Reprogram the key
In some cases, your key may simply need to be reprogrammed. Your car owner's manual should tell you the basic method for reprogramming a transponder, or if this is something that only the dealership can do. Some keys can also be reprogrammed by locksmiths that aren't affiliated with the dealer. If you are able to do it yourself, it is usually a simply process of turning the key between the accessory, on, and off position in a certain order.
For more information or other tips, check out websites like http://www.alocksmithriverside.com.