Security light flashes
Antitheft or Security system failure is a common problem on GM vehicles. Every time you put your key in the ignition, the vehicle's security system reads the signal from your key to make sure it is OK to run. When it recieves the "correct key" signal, the security system allows the starter to turn over, and/or the fuel injectors to function and your car works like it normally does every day. If you were to use a different key, or try to hotwire it, the system would shut down these parts of your car, thus making the vehicle completely immobile. This is GM's way of preventing vehicle theft. The problem is that the system is known to fail quite commonly. It has been failing consistantly for around 30 years. When it fails, two things can happen. First, you turn the key and nothing happens at all. Lights work, radio works, windows work... just not the starter that you need to start the vehicle. This is a "starter immobilizor". Second, you turn the key and the vehicles starts just fine, but then stalls in 2-5 seconds. This is a "fuel immobilizor". It literally cuts off the fuel injectors and stalls the vehicle to immobilize it. These are normally, but not always followed by a light on the dash that says SECURITY or ANTITHEFT. These lights are to inform you of the system's failure to collect the information it needs from your key to the computer. If your security/antitheft light is on, odds are you will be stranded soon, if not already. Remember that the security system controls the security light. If the system is failing, the light may never warn you of the failure. There is a lot of info on this site that you can read up on. http://vatspasslockpasskeysecurityhelp.yolasite.com/
