Fault phenomenon, a Santana equipped with second generation of anti-theft system 2000 early morning after the start of fire. Troubleshooting and troubleshooting the vehicle maintenance task is to rush out for repairs, switch on the ignition after receiving the vehicle, immediately extinguish after starting, and the engine oil circuit does not supply oil. Considering the oil pump that the car had just changed, and not enough testing equipment, the car was towed back to the repair shop for further inspection. After careful analysis of the fault phenomenon, it is very likely that the anti-theft system is locked. The car's anti-theft indicator lights flicker, indicating that the anti-theft system has entered the protection state. The code is adjusted by VAS5052. The fault code is 01176, that is, the key signal is too small to be recognized and the 17978 engine control module is disabled. The key to the ignition switch is not the original vehicle, but the vehicle owner's own key to open the door. Since the car is equipped with the second generation of anti-theft system, its key is equipped with chips, and ordinary keys can not start the car properly. After the failure of the code to start the car with the original key to start the car or can not start, continue to use VAS5052 to adjust the fault code, and the previous fault code, the suspect is the illegal key has been saved the system to eliminate the data, so the code is eliminated with the VAS5052 key matching (the original 4 bit code needs). After rematching the key, turn on the ignition switch and the fault will disappear. Maintenance summary: this car's fault is entirely caused by the owner himself, and often encountered similar things during the maintenance process. Here I would like to remind us that there are people who have a car to read more about their own cars, and know more about the common knowledge of cars. Expert comments on the case should be a very obvious fault, according to the failure phenomenon can immediately be very clear to know the trigger caused by the anti-theft system, as long as the cause of the anti-theft system triggering and then the anti-theft system matching can be successfully solved. It needs to be explained that the fault phenomenon described by the author is very general -- "after starting and stalling." In fact, the method of describing the failure phenomenon is not conducive to the correct analysis and removal of the fault, so the author wrote in the article: "after careful analysis of the failure phenomenon, there may be a lock on the anti-theft system." In fact, the phenomenon of the car should be described as: "a second generation of anti-theft system in Shanghai Santana 2000GSi car, immediately after the start of the fire, and the instrument on the burglar lights flicker." As long as we see such a failure phenomenon, we can immediately determine that the vehicle fault is triggered by the burglar alarm system, and the maintenance idea is very clear. A large number of computers are used in modern cars, especially many vehicles are also connected in vehicle computers, and each computer has to communicate with each other. So when the information of vehicle failures is read, it is very important to find out what the fault information is read from the computer. Although the Shanghai Santana 2000GSi car has not used the vehicle network system, it should also find out the source of the fault information when reading the fault information, which is also very beneficial to the troubleshooting. The fault code 01176 should be read from the anti-theft ECU (J362), and the fault code 17978 should be read from the engine ECU (J220). It can not be expressed in a general way as "VAS5052 code, fault code: 01176 that the key signal is too small to be disapproved and the 17978 engine control module is forbidden." Now that we read out the fault code, we must carefully analyze the meaning of the fault code. In fact, the fault code 01176 has 2 meanings in the maintenance manual: one meaning is "the key signal is too weak", the possible cause of the failure is the read-out coil or wire damage (contact resistance / contact loosening), the pulse transponder in the ignition key is malfunction or failure, the ignition key is wrong, and the other meaning is "the key is not suitable." The reason for the failure is that the ignition key inserted into the ignition lock core has not been matched. According to the meaning of the fault code, it is immediately clear that the key should be checked correctly. The fault code 17978 means "the engine control module is locked". The cause of the failure is: starting with the illegal key; the code is not correct; the anti-theft system failure; the burglar control unit failure / failure; the replacement of the engine control module is not matched with the electronic burglar alarm; the communication line circuit short circuit. No matter which fault code appears above, the failure phenomenon is "immediately flameout after the engine starts, and the anti theft indicator lights on the dashboard". Such 2 fault codes have fully demonstrated that the root cause of the failure is the triggering of the anti-theft system. The 2 fault codes have the reasons for the failure of the ignition key, so reading these two fault codes should first check whether the ignition key is correct, so that the reason for finding the fault is very easy and smooth. As we all know, the process of automobile fault diagnosis is the same as that of a doctor. The first step of fault diagnosis should be to inquire the causes and consequences of failures in detail. In fact, as long as the maintenance personnel detailed inquiries about the car's failure, the car owner will definitely talk about the use of their own keys, so the cause of the failure suddenly became "bald head on the lice - clear up!" There's no need to spend so much on it. Therefore, there is a very important method of fault diagnosis in fault diagnosis, that is, "inquiring", also known as "customer survey". Someone wants to ask, what should we ask as a vehicle maintenance worker when a malfunctioning vehicle comes? According to my own maintenance practice, the contents of user enquiries mainly include the following aspects: 1. It is a city road or a country road to master the condition of a car, which is a city road or a country road; a car is often running at low speed or at a high speed; is it often running at low speed in the city; what kind of gear is often used and the mileage of a car. 2. maintenance of the situation. For example: the time of the last three filters, what time was the engine oil and the transmission oil replaced, and if the oil liquid level was in the specified range, which sensors were disassembled and which parts were dismantled and adjusted, which all help to judge the failure.