Design of embedded vehicle fault instrument based on OBD-II
基于OBD-II的嵌入式汽车故障诊断仪设计

摘要

本文首先介绍了汽车故障诊断仪的发展，然后介绍了OBD-II的基本操作方法，并根据诊断仪的技术要求，来给出了车辆故障诊断仪的基本设计方案，从而提出了一个现阶段使用较为普遍的第二代在线故障诊断技术（OBD-II）的便携式车辆故障诊断仪，该系统通过单片微型机件捕捉系统所提供的信息，经过协议解析和接口电路电平的调理，即可实现与车辆ECU之间的直接通讯，实现提取和消除车辆的故障码。本文所设计的诊断仪具有费用便宜、安全性好、使用方便、容易推广的优势。

Abstract

This paper first introduces the development of vehicle fault diagnosis instrument， and then introduces the basic operation method of OBD-II， and according to the technical requirements of the diagnostic instrument， to give the basic design scheme of vehicle fault diagnosis instrument， thus put forward a common second generation online fault diagnosis technology （OBD-II） portable the system， through the information provided by the system， through the protocol analysis and interface circuit level conditioning， can realize the direct communication with the vehicle ECU， extract and eliminate the vehicle fault code. The diagnostic instrument designed in this paper has the advantages of cheap cost， good safety， easy to use and easy to promote.