Theft light wont go off but car does start - 2003 Chevrolet Malibu

SOURCE: the Anti-Theft Light Flashes and car wont start

Use the other ignition key and see what happens. You can have a faulty key now. A transponder is embedded inside the keys head that makes the starter to work off the computer

SOURCE: When anti theft light is blinking the car wont

On a 2003 Chevy Maibu the theft system light comes on and blinks when the system is triggered. The car will not start and the fuel pump cuts out. You must turn key to on and have all doors closed. Keep the key to on for 10 mins til theft light turns solid and then disappears. Then turn key to start and it should fire up.

SOURCE: how do i by pass, or disconnect the theft security

Eventually you will have to get the pass code from the dealer with the vin# to the car,Which means you will have to buy a lock switch remote for that car. For now, disconnect the battery for 10 minutes and it will re-set it self.