The automobile's power, economy, handling stability and safety are changed in the process of automobile use because of various reasons. Vehicle failures are sudden and some are gradually formed. When a car fails, it can accurately diagnose the cause of the failure, find out the damaged parts and parts, and remove the fault as soon as possible with the experience and scientific knowledge. It is beneficial to the use and maintenance of the car. The causes of automobile failure are as follows: the main causes of automobile failure are as follows: 1. it is impossible to achieve the same life of all parts in the car, and some parts of the car itself are vulnerable parts, such as air filter core, spark plug, oil and so on. Short, all need to be changed regularly, if there is no timely replacement or damage to the car ahead of time, it will malfunction. 2. the quality difference between parts and parts of automobiles and automobile parts is produced in large quantities and produced by different manufacturers. Inevitably, there are quality differences. There will be problems in the use of the parts of the original plant. The cooperation plant and unqualified accessories will be more difficult to install on the car. Therefore, all the auto manufacturers are trying to improve the quality of the parts and eliminate the quality defects of the parts themselves. 3. the quality difference of automobile consumables is mainly fuel and lubricating oil. The poor quality of these products will seriously affect the performance and service life of the car, and make the car easier to fail. The addition of these supplies is often difficult to be guaranteed by users. Less attention will be added to inferior gasoline and inferior lubricating oil. It is very harmful to cars and engines, and the users are not concerned about the problem. 4. when the vehicle is used in the environment, the automobile is used in the open air, and the environment has great influence. The expressway is wide and flat, with high speed, easy to break down and accident. The road is uneven, and the vehicle vibrate and vibrate seriously. The power consumption of the mountain area is large and the time of the city is long and so on, so the use of the car is changed greatly. Sometimes it is easy to fail or cause sudden damage when it is not adapted. 5. driving technology and driving method affect driving technology greatly, and improper use method has greater impact. Bad management of vehicles can not be carried out in accordance with regulations and regular maintenance. Barbaric starting and barbaric driving will cause early damage and failure. 6. the technology of automobile fault diagnosis and maintenance technology should be repaired regularly. In automobile use, maintenance, fault diagnosis and maintenance work, technology is needed, especially modern cars, and high and new technology is used more. This requires the automobile use and maintenance staff to understand and master auto technology and advanced new technology. No repair, no repair, no understanding, no movement, so that the old disease will not be eliminated, and new problems will arise. Therefore, automobile failure is widely used in the whole process of automobile manufacturing, use, maintenance and repair. It should be paid great attention to every link, especially in the use of automobile failure. In order to reduce accidents in the process of use, the car should be found in time and eliminated in time. Common faults of automobiles are common faults of automobiles, which can be judged by experience, sense organs and instruments. The common faults are as follows: 1. abnormal performance of automobile performance abnormal automobile is the poor power and economy of the car, which is mainly manifested in the lower driving speed of the automobile, the poor acceleration performance of the car, the large fuel consumption and the large oil consumption. The riding comfort of vehicles is poor, and the vibration and noise of vehicles are obviously increased. Vehicle handling stability is poor, the car is prone to deviation, vehicle shimmy, braking deviation, long braking distance or no brake. 2. a sudden abnormal phenomenon occurred during the use of a car with abnormal car use. It should be prevented: the engine suddenly flameout; the car has no brake when it needs to be brake; the car can't start in winter; the engine can't start after the engine is extinguished; the steering suddenly loses its spirit; and more car blowout and steam. Car fire and so on. Symptoms are more obvious, the causes are more complex, mainly due to internal faults, which have not been noticed and developed into sudden damage. 3. the abnormal noise of vehicles, the breakdown of vehicles, often the most abnormal voice in the form of expression. Under normal circumstances, both drivers and passengers can hear. The experienced person can judge the car fault according to the different frequency and sound of the sound. Generally the noise is more dull and the fault is more serious with the stronger chattering. It should stop, reduce the engine speed or turn off the engine to look up. Some parts of the sound are in trouble and do not affect the steam. The vehicle can not be found at any time. It can drive the vehicle back to the base or drive into the vehicle maintenance department nearby. Please find experienced personnel. 4. the most unusual smell of cars is the smell of cars. People smell very sensitively and smell. The first thing to judge is whether the smell of the car or the smell of the environment. The odor mainly includes the odor of the nonmetallic friction material on the brake and the clutch; the special odor of the battery electrolyte; the burnt smell of the electric system and the wire of the car. At some point, it is necessary to pay attention to the smell of burning oil and abnormal gasoline. 5. the overheating of automobiles is manifested by the fact that the temperature of all parts of the vehicle exceeds the normal temperature range. When the engine is overheated, the performance of the heat sink is most obvious; the overheating of the transmission, the overheating of the rear axle housing and the overheating of the brake can be shown by hand test or water test. The overheating of the car can be further checked to find the root of the failure, such as the long time high load, which generally does not affect the use. If the internal mechanism fails, it should be diagnosed and eliminated in time. 6. exhaust smoke color abnormal engine exhaust smoke color is the appearance of the engine performance. The engine is burning normally and has a certain exhaust smoke color. When the engine is not working properly, the exhaust smoke color changes. The engine oil exhaust is blue, indicating that the engine needs to be repaired; the engine combustion incomplete exhaust is black, the fuel should be replaced or the ignition timing should be adjusted; the engine exhaust is white, indicating that there is water in the fuel or cylinder, and the fuel or the engine should be checked. 7. leakage of automobile leakage car shows oil leakage, oil leakage, leakage of coolant, leakage of brake fluid, leakage of steering oil, leakage of lubricating oil and refrigerant leakage, as well as leakage of battery liquid and electrical system in electrical system. Vehicle leakage is extremely likely to cause overheating and structural damage. For example, leakage of steering oil is easy to cause steering failure, and brake fluid is liable to cause brake failure. 8. when the car is parked on a flat site, the inspection appearance sometimes finds the longitudinal deviation or lateral skew of the car, showing the appearance of abnormal appearance. Attention should be paid to the abnormal phenomena such as tire pressure, frame and suspension damage, body damage and so on. The abnormal appearance of a car may affect the use of the car. For example, vehicle gravity center deviation, serious vibration, unstable steering and vehicle deviation.