Automotive came out and during use, due to various reasons inevitably fails, to power cars, economy, handling stability, security and other changes in use. We can use diagnostic tools launch x431, lexia3, mb star. Some unexpected car trouble, some are evolving. When the car fails, experience and scientific knowledge can be used quickly and accurately diagnose the cause of the malfunction, to identify damaged parts and parts, and troubleshooting as soon as possible on the vehicle's use and maintenance of benefit. Car, this modern means of transport, from the manufacturing factory of the day, no matter how they talk, there is a certain life. No matter how used, sooner or later are to be bad, so do not use the failure is relative, and a variety of fault occurrence is inevitable. Therefore, the reasons for failure analysis and diagnosis, help to make judgments, so that car in good condition in the case of technology running. Reliability and easy maintenance from the point of view, automotive electronic control system should be equipped with self-diagnostic function; since the 80's GM vehicles the United States developed the first in a new electronic control system malfunction self-diagnostic function to add, the global world-class car manufacturers emulate, have produced in various electronic control systems equipped with a fault in the self-diagnostic function; after a long period of development, self-diagnostic module will not only address the safety of automobile electronic control systems and vehicle storage memory failure also able to provide immediate car produced by a variety of system operation parameters. Since then, the "car fault self-diagnosis function" has become the new car factory and car repair workshop fault detection problem indispensable helper. Automotive fault forming because of the following areas: Itself vulnerable parts exist. Do not overlook the use of launch x431. Automotive design is not possible all the parts car has the same life, some parts for the car itself, wearing parts, such as air filter core, spark plugs, engine oil life is shorter, need to be changed regularly, if not timely damaged cars will be replaced or early failure. Differences in the quality of parts itself. Auto and auto parts are high-volume and produced by different manufacturers, there is inevitably the quality difference. The use of original parts will have problems, collaborative works and substandard parts fitted to the car will have problems, all car manufacturers are working hard to improve the quality of parts, elimination of components and quality defects. Differences in the quality of automotive consumables. There are cars on consumables such as fuel and lubricants, these added supplies of poor quality will seriously affect vehicle performance and service life, making the car more prone to failure. Add these items is often difficult for users to ensure that little carelessness will join the low-quality gasoline and low-grade oil, cars and engines on the great harm, potential users do not care, car on a problem. It seems that a car using the environmental impact. Open-air vehicle for the use of a larger environmental impact. Pavement broad and smooth, high-speed car, failure and accident-prone; road uneven, bumpy car vibration serious injury prone. Mountain power consumption, the city waiting for the bus a long time and so make use of vehicles has greatly changed conditions, and sometimes can not adapt to the time and lead to failure, or cause unexpected damage. Technology can be used simultaneously with lexia3. Driving skills and driving method of. Driving the car failure a great impact, greater use of undue influence. Poor management of motor vehicles not required to take the combined and periodic maintenance, driving and so barbaric and brutal will start early damage and car crashes. Automotive fault diagnosis and repair technology impact noon. Car use to regular maintenance, a fault to make accurate diagnosis in order to fix. In the car use, maintenance, fault diagnosis and repair operations are Xuyao skilled, especially Hyundai, Technology Application in more, which requires Qiche use, maintenance personnel should understand and master the advanced vehicle technologies and new technologies. No repair and not to collect maintenance, do not know can not tamper with so old disease is not eliminated, new problems will emerge. Therefore, the car breakdown widely present in the vehicle's manufacture, use, maintenance and repair work of the whole process, for each link should be great attention, especially in the use of cars should pay attention to the failure, there is failure to discover and remove , can reduce automobile use during the accident occurred. More useful diagnostic techniques have mb star. Cars in use, the inevitable to various problems. Car traffic on the way, the failure to spot checks by the car driver, on the spot diagnosis on the spot troubleshooting, can the vehicle to continue driving; some larger or more complex fault car driver difficult themselves to the car mechanics and vehicle maintenance technicians to check the diagnosis, rule out the possibility. Car trouble changing, strange variety, but the fault diagnosis methods and steps are certain, as long as the basic method is correct, clear, appropriate methods, fault diagnosis is easily made.