维修技师通过试车发现变速箱只有2档、4档、6档、倒档，除了黄色齿轮灯点亮以外，还发现仪表显示屏会显示“变速箱故障功能限制可继续行驶”的字样，用诊断仪检查，报有子变速箱1故障(主动/静态)故障码。

The maintenance technician found through a test drive that the gearbox only has 2nd, 4th, 6th, and reverse gears. In addition to the yellow gear light on, they also discovered that the instrument display screen would display the words "Transmission fault function limit can continue driving". After checking with a diagnostic tool, a fault code (active/static) for sub gearbox 1 was reported.

首先从故障码的字面上来理解故障问题，子变速箱1是指奇数档，根据资料得知，阀3就是控制奇数档动力传递的管理K1离合器的电磁阀N435。故障性质既然是静态的故障，那么说明肯定也是硬性故障(系统存在真实问题)。当然，在这种情况下故障码肯定也是删除不掉的，因此变速箱起动应急模式切断了K1离合器的工作，此时奇数档全部失效而仅保留偶数档部分。这说明问题将会将会出现在电控系统或者电路上。既然报的故障是变速箱的阀3，那么首要考虑的是与电磁阀3电路相关的。结合维修资料，首先找到这个电磁阀。

Firstly, to understand the fault problem from the literal meaning of the fault code, sub gearbox 1 refers to odd gears. According to the data, valve 3 is the solenoid valve N435 that controls the transmission of power to the K1 clutch in odd gears. Since the nature of the fault is static, it indicates that it is also a hard fault (there is a real problem with the system). Of course, in this situation, the fault code cannot be deleted. Therefore, the emergency mode of the transmission cuts off the operation of the K1 clutch, and all odd gears are disabled while only the even gears are retained. This indicates that the problem will occur in the electronic control system or circuit. Since the reported fault is valve 3 of the gearbox, the primary consideration is related to the circuit of solenoid valve 3. Based on the maintenance information, first locate this solenoid valve.

排放变速箱油拆卸变速箱油底壳，并将机电控制单元总成小心的拆下来，并断开电磁阀连接的线板。首先利用万用表对其N435电磁阀本身进行线圈阻值的独立测试。

Drain the transmission oil, remove the transmission oil pan, carefully disassemble the electromechanical control unit assembly, and disconnect the wire board connected to the solenoid valve. Firstly, use a multimeter to independently test the coil resistance of the N435 solenoid valve itself.

通过万用表的测量，N435电磁阀在不同温度下的电阻也在正常范围内，说明电磁阀本身是好的。然后将线板与变速箱控制单元的插头拔掉，并把线板的另一端与电磁阀进行连接，从控制单元插头出处找到N435电磁阀的相关针脚。直接从控制单元输出端对电磁阀的电阻再次进行测量发现，电阻值变得无穷大，说明问题出在控制单元输出端至电磁阀之间的线路上。如果电磁阀本身没有问题，控制单元输出端值电磁阀间的线路也没有问题，说明问题在控制单元方面了。

According to the measurement of the multimeter, the resistance of N435 solenoid valve at different temperatures is also within the normal range, indicating that the solenoid valve itself is good. Then unplug the plug between the wiring board and the transmission control unit, and connect the other end of the wiring board to the solenoid valve. Find the relevant pins of the N435 solenoid valve from the control unit plug. Directly measuring the resistance of the solenoid valve from the output terminal of the control unit again, it was found that the resistance value became infinitely large, indicating that the problem lies in the circuit between the output terminal of the control unit and the solenoid valve. If there is no problem with the solenoid valve itself and there is no problem with the wiring between the solenoid valves at the output of the control unit, it indicates that the problem lies with the control unit.

通过这种测量不难发现，问题出在线路板(因为控制单元输出端至电磁阀间的线路连接直接隐藏在这个线路板里面)。因线路板电阻值的变化，控制单元到N345电磁阀的电流不能形成一个完整的回路，即使发动机没有运转，打开点火开关以后，车辆也会有个自检，也会报有相应的故障码，这也是为什么故障码不能删除的主要原因。

It is not difficult to find through this measurement that the problem lies in the circuit board (because the wiring connection between the control unit output terminal and the solenoid valve is directly hidden inside this circuit board). Due to changes in the resistance value of the circuit board, the current from the control unit to the N345 solenoid valve cannot form a complete circuit. Even if the engine is not running, after turning on the ignition switch, the vehicle will have a self check and report corresponding fault codes. This is also the main reason why fault codes cannot be deleted.