OBD III standard and its predecessors OBD I and OBD II

Abstract

Vehicular transportation is an integral part of our life these days and the number of vehicles on road is also increasing day after day causing increase in traffic congestion. Hence the emission control and check is the utmost requirement nowadays. On board diagnostic was developed and implemented to reduce vehicle emission and was first time standard was set by California. This system identify the sensors/actuators, system and subsystems of power train system which are likely to increase emissions when malfunction during operation. This paper studies OBD III standard and compares with OBD I and OBD II.OBD (On Board Diagnostics) is the vehicle’s self-diagnostic system. It allows for accessing various engine’s diagnostic data from the ECU such as DTC codesfrom cars, medium-duty and heavy-duty vehicles. Practically we have use an OBD II scanner to read the engines internal data to identify the underlying issues behind a malfunction indicator light(MIL). OBD-II was designed to allow to checkwhether the vehicles were meeting the emissions standards or not. OBD III is the advanced standard of OBD II. OBD-III allows to reduce the delay in detection of an emissions malfunction by the OBD-II and also allows to repair of the vehicle.The objective of this study is to demonstrate the feasibility and effectiveness of replacing the current emissions-based periodic inspection and maintenance (I/M) program with automated inspections based on the OBD-II system and an on-vehicle radio transponder.