Abstract: A security system for selectively enabling and disabling the internal combustion engine of a vehicle is provided. The security system includes a security module which selectively interrupts current to or from crucial vehicle subsystems which are necessary for engine ignition or engine operation. The security module attaches and locks to the electrical terminal of a vehicle subsystem so that the security module cannot be removed from the engine compartment of a vehicle without removing the entire vehicle subsystem. Moreover, the security module covers and isolates the electrical terminal of the vehicle subsystem so as to electrically isolate the electrical terminal from unauthorized access. The security system further includes a controller and a switching element which are located within the security module for selectively controlling the flow of current from a conductive path to or from the vehicle subsystem which is sought to be controllably enabled and disabled.