Abstract: A vehicle anti-theft system includes an engine control computer operable to control engine fueling in a normal mode of operation according to operator demand via an accelerator pedal, and a code interface module responsive to a predefined security code to set the engine control computer in a secure mode of operation. In the secure mode, two fuel enabling values in the engine fueling algorithm are altered. Specifically, an engine startup enable value is altered so that the engine control computer disables fueling if the engine is not running, to thereby prevent an unauthorized individual from starting the engine. Likewise, an accelerator enable value is altered so that the engine control computer disregards the accelerator signal and controls fueling of the engine to thereby maintain an engine idling condition. The control computer is reset to its normal fueling control mode by re-entering the security code.