Q: for the failure of the automatic transmission control system, the fault code is usually stored in the control unit, so the maintenance personnel need to connect the fault diagnosis instrument to detect the system. When the equipment displays the relevant fault codes, how should the maintenance personnel use these fault codes to troubleshooting faults? Answer: when the automatic transmission control system stores the fault code, the connection fault diagnosis instrument can read the fault code. When analyzing the fault, it is necessary to analyze the meaning of the fault code. At the same time, we must master and understand the condition of setting the fault code in the control unit.