The vehicle OBD diagnostic line interface can monitor the working conditions of the engine electronic control system and other functional modules of the vehicle in real time during the vehicle operation. If abnormal working conditions are found, the specific fault can be determined according to the specific algorithm and stored in the memory of the system in the form of diagnostic trouble codes (DTC).

The useful information obtained from the self-diagnosis of the vehicle OBD diagnosis line can provide help for the repair and maintenance of the vehicle. The maintenance personnel can read the fault code using the special instrument of the original vehicle factory, so that the fault can be quickly located, so as to facilitate the repair of the vehicle and reduce the time of manual diagnosis.

The vehicle OBD diagnostic line is connected to the electronic control unit (ECU) through various emission-related component information. The ECU has the function of detecting and analyzing emission-related faults. When an emission fault occurs, the ECU records the fault information and relevant codes, and sends a warning through the fault lamp to inform the driver. ECU ensures access and processing of fault information through standard data interface.