Abstract: A vehicle theft prevention device which simply disables the engine control module (E.C.M) of a motor vehicle is disclosed. The device gives the user of the automobile the capacity to activate or deactivate the E.C.M. When the E.C.M. is deactivated the engine would crank but would not turn over, as the E.C.M. has been isolated form the electrical system. The device isolates the E.C.M. via the vehicle's fuse box. The device comprises a fuse box diverter which replaces the E.C.M fuse in the factory fuse box located in the interior of the vehicle. The fuse box diverter is connected to a switch by electrical wiring. Intermediate the switch and the fuse box diverter is a fuse element secured in an in-line fuse holder. By actuating the switch the circuit is disabled. The switch and the in-line fuse holder may be located at a remote location in the vehicle. The vehicle theft prevention device is very easy to install and requires no physical alterations to the existing vehicle electrical system.