At the beginning of OBD, it was only to monitor whether the emission of exhaust gas exceeded the standard. With the increase of regulatory requirements for environmental pollution emissions, the continuous development and innovation of vehicle networks and smart cars, the expansion of OBD functions has become more widespread in the field of passenger vehicles. The use of the OBD extension function is closely linked to the willingness of the majority of vehicle owners to consume, driving habits, the ecological environment of the car network, and the support of the automobile industry. Therefore, the OBD function expansion and application of the road is a long way to go.