A vehicle security system may disrupt communications on a vehicle data communications bus, such as to prevent starting of the vehicle engine. The vehicle security system may include at least one vehicle security sensor, a vehicle data communications bus disrupter for disrupting communications on the vehicle data communications bus, and a security controller for selectively operating the vehicle data communications bus disrupter. The disrupter may be operated based upon the at least one vehicle security sensor to thereby disable the vehicle engine. The disrupter may alternately be operated based on a signal from a monitoring station that receives position information from the vehicle.