If your car has developed a problem where it will start but won't idle and instead turns itself off, then there is likely a problem with its security system. The reason the vehicle won't run is that the car's onboard computer tells the fuel supply to shut off because it thinks someone is trying to steal the car. This situation is very annoying for car owners and can be very hard to diagnose even for the most skilled mechanics.
To troubleshoot your car's problem and determine if the security system is the issue, here are some additional information and suggestions about what you can try:
Key Fobs and Resetting the Security System Using It
Many of the security systems installed in vehicles today require that you use a specialized key that has a computer chip installed inside of it. The chip interfaces with the car's main computer and it is designed to prevent theft of your vehicle by someone who doesn't have its key.
If you locked your vehicle using the key fob and then reached into your car through a cracked-open window and unlocked the door, then the security system may still be engaged. When you try to start the car with the key, the car's computer thinks it is being stolen and cuts the fuel supply.
You can easily reset the security system by locking each of your car's doors using the key. Wait for a few minutes and then unlock each door with the key. Try to start your car and see if this fixes the problem. If not, you may need to reboot the car's computer.
Reboot the Computer by Disconnecting Its Power Supply
If locking and unlocking the car doors didn't fix the problem, then you should try rebooting your car's computer. The easiest way to do this is to remove both the positive and negative battery cables and let your car sit for a few minutes. As the power discharges the computer will turn itself off. Reconnect the battery cables and try starting your car. If the car still won't idle, then the computer's firmware needs to be flashed.
Have a Local Automotive Dealership Flash the Computer's Software
Finally, just as with any other computer, your car's computer's software can become corrupted and stop communicating properly with the chipped key. When this happens, you will need to tow your car to your local automotive dealership and have the computer's software reinstalled. Once the software has been reinstalled, then the computer will once again be able to effectively communicate with the key and your car will work as it is supposed to.
For more information, talk to a company like Johnny Locksmith.