Fault phenomenon: a 2002 automatic file Sena 2, the engine type is MM6LP. The car suddenly stopped running and could not start. Troubleshooting and Troubleshooting: using Dongfeng Citroen PROXIA special diagnostic instrument to detect engine electronic fuel injection, the computer can not carry out dialogue. Detection of BSI intelligent server computer, read fault: "P and engine ECU communication failure (local)"; "P vehicle longitudinal acceleration information failure (isolated)"; "P engine water temperature information fault (local)"; "P speed information failure (isolated)". Testing automatic transmission computer, reading fault is: "P - throttle potentiometer signal failure (isolated)"; "P automatic transmission and engine computer dialogue failure (isolated)." Note: the above "local" refers to the fault information that is directly received for this computer. "Separated" means that the fault information is released to the CAN system by other computers. The above "F" represents a temporary fault, and "P" stands for permanent fault. The engine ignition and fuel injection are checked, and the nozzles are found to have no working signals, but the engine can start the normal work and the fire is normal at the inlet. According to the analysis of the above inspection results, because of the use of multiple transmission systems in the Seine car, the engine EFI computer and the BSI and the automatic transmission computer three constitute the CAN system and share information with each other. If any part of the CAN system has short circuit or circuit breakage or one of the computer damage, there will be a computer dialog failure. In this case, the BSI and the automatic transmission computer all have a dialogue fault, indicating that the CAN system has a problem. Disconnect the battery, remove the three computers, and use the multimeter to check the CAN line connection between each other. There is no open circuit and short circuit. And see three computers one by one, found that the electronic injection computer several needle and foot obviously corrosion phenomenon, combined with the front PROXIA diagnostic instrument can not enter the electronic injection computer analysis, should be the electronic injection computer failure. Replace the engine electronic injection computer, troubleshooting.