Common can communication interface failure phenomenon and so

Cars are the means of transportation that we can often contact with. They are fast, easy to operate and low in maintenance cost. They are favored by people. As long as conditions permit, everyone likes to drive out. However, because the car is a living human, so its normal operation is really very important. We don't need to mention the common engine and tire maintenance, which are all the places that must be focused. In fact, not only these eye-catching positions need our attention, but also the CAN bus which is not easy to see. It is also worth us to take seriously. Next, let's briefly talk about the CAN bus and the common problems that may occur.


Can bus is the abbreviation of controller area network, which is a common industrial field bus, that is, control communication system. The data transmission speed of CAN bus is fast, and the highest baud rate value reaches 1000kbps. The data transmission distance is far, and there are signals 10 kilometers away. In theory, one can bus can connect 110 nodes. The later maintenance cost is low. Because of the use of differential voltage signal transmission mode of twisted pair, the operation of CAN bus is relatively stable and not easy to be damaged by external interference. To say the least, even if the nodes on the CAN bus have problems due to external interference, they will actively cut off the connection with the bus, and will not continue to send the wrong data, resulting in the collapse of the whole line. In the later stage, the number of maintenance is generally relatively small, saving time and effort. Because of these advantages compared with other buses, can bus is widely used in industrial automation control, tram control, fire control host networking, artificial intelligence development and other fields, known as one of the most promising industrial buses. Of course, can bus is developed by human beings, which means that it also has the possibility of problems, such as:

1. Faults caused by automobile power supply system: the working voltage of automobile electronic control module is generally 10.5-15.0v. If the working voltage provided by automobile power supply system is abnormal, some electronic control modules will work abnormally for a short time, which will cause the communication of the whole automobile can bus system to be blocked.
2. Link failure of automobile can bus system: in case of short circuit, open circuit of communication line or change of physical property of the line which causes attenuation or distortion of communication signal, it will lead to abnormal operation of multiple electronic control units and make can bus system unable to work.
3. Node fault of automobile can bus system: node is the electronic control module in automobile can bus system, so node fault is the fault of electronic control module. It includes software fault, that is, the transmission protocol or software program has defects or conflicts, which makes the communication of automobile can bus system disordered or unable to work, this kind of fault usually appears in batches; hardware fault is generally the fault of electronic control module chip or integrated circuit, which causes the automobile can bus system unable to work normally.
Of course, if there is a problem, we should start to solve it. Next, we will talk about some methods to solve the problem of automobile can bus:

1. Measure the terminal resistance value
2. Measurement of can-l or can-h to ground voltage
3. Waveform measurement of automobile can bus system