The OBDII computer monitors a vehicle’s emission control systems in real time and is capable of informing a motorist or technician of a systemic issue the moment it occurs. The system operates through a series of indicator lights, drive cycles, trouble codes, and readiness monitors. During an inspection, an emission analyzer scan tool plugs into the diagnostic connector that is attached to the OBDII computer and communicates with the vehicle. The OBDII computer relays to the scan tool whether it has discovered errors in the emission control systems. The emission analyzer then determines whether the vehicle is being operated in compliance with emission standards.