The maintenance technician found that the gearbox only has 2, 4, 6 and reverse gears through test run. In addition to the Yellow gear light on, they also found that the words "gearbox fault function limit can continue driving" will be displayed on the instrument display screen. After checking with the diagnostic instrument, the sub gearbox 1 fault (active / static) fault code is 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。

First of all, understand the fault from the literal fault code. Sub gearbox 1 refers to odd gear. According to the information, valve 3 is the solenoid valve n435 which controls the power transmission of odd gear and manages K1 clutch. Since the nature of the fault is a static fault, it must be a hard fault (there are real problems in the system). Of course, in this case, the fault code must not be deleted. Therefore, the emergency mode of gearbox starting cuts off the work of K1 clutch, and at this time, all odd gears are invalid and only even gears are retained. This shows that the problem will appear in the electronic control system or circuit. Since the reported fault is transmission valve 3, the primary consideration is related to the solenoid valve 3 circuit. Combined with the maintenance information, first find the solenoid valve.

自动变速箱维修

Automatic transmission maintenance

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 remove the electromechanical control unit assembly, and disconnect the wire board connected with the solenoid valve. Firstly, the coil resistance of n435 solenoid valve is tested by multimeter.

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。

Through the measurement of 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 pull out the plug between the wire board and the transmission control unit, connect the other end of the wire board with the solenoid valve, and find the relevant pin of n435 solenoid valve from the plug of control unit. The resistance of the solenoid valve is measured directly from the output end of the control unit. It is found that the resistance value becomes infinite, 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, there is no problem with the circuit between the control unit output value solenoid valves, indicating that the problem lies in 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。

Through this measurement, it is not difficult to find that the problem lies in the circuit board (because the circuit connection between the output of the control unit and the solenoid valve is directly hidden in the circuit board). Due to the change of circuit board resistance value, the current from control unit to n345 solenoid valve can not form a complete circuit. Even if the engine is not running, the vehicle will have a self-test after turning on the ignition switch, and the corresponding fault code will be reported. This is the main reason why the fault code can not be deleted.

奥迪Q5变速箱故障维修：

Troubleshooting of Audi Q5 transmission:

解决这个问题并不需要更换机电控制单元总成，只需要更换连接电磁阀的线路板就可以了。更换线路板后需要用专用诊断仪对变速箱进行引导功能的设定，并做离合器的自适应学习。除了更换线路板之外还有变速箱内外滤清器、油底垫以及专用变速箱油。引导匹配完毕后慧众维修技师进行试车，确定换挡品质问题及故障是否已经排除。经过长时间的试车，确定故障没有再出现以及没有其他故障，此时故障彻底排除。

To solve this problem, it is not necessary to replace the electromechanical control unit assembly, just replace the circuit board connecting the solenoid valve. After replacing the circuit board, it is necessary to use a special diagnostic instrument to set the guiding function of the gearbox and do adaptive learning of the clutch. In addition to replacing the circuit board, there are also internal and external transmission filters, oil mats and special transmission oil. After guiding the matching, Huizhong professional maintenance technicians conduct test run to determine whether the shift quality problems and faults have been eliminated. After a long time of test run, it is determined that the fault does not recur and there are no other faults. At this time, the fault is completely eliminated.