Vehicle Readiness
OBD II technology monitors all components of the engine management system and can detect a malfunction or deterioration of these components usually well before the driver becomes aware of any problem. Vehicles equipped with OBD II self-test their emission systems while the vehicle is being driven. Vehicles perform up to 11 system tests, depending on year, make and model of the vehicle. Readiness status identifies whether the vehicle's computer has completed the required tests since the last time the vehicle was serviced with a scan tool or had its battery disconnected.