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.

首先從故障碼的字面上來理解故障問題，子變速箱1是指奇數檔，根據資料得知，閥3就是控制奇數檔動力傳遞的管理K1離合器的電磁閥N435。故障性質既然是靜態的故障，那么說明肯定也是硬性故障(系統存在真實問題)。當然，在這種情況下故障碼肯定也是刪除不掉的，因此變速箱起動應急模式切斷了K1離合器的工作，此時奇數檔全部失效而僅保留偶數檔部分。這說明問題將會將會出現在電控系統或者電路上。既然報的故障是變速箱的閥3，那么首要考慮的是與電磁閥3電路相關的。結合維修資料，首先找到這個電磁閥。

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.

自動變速箱維修

Automatic transmission maintenance

排放變速箱油拆卸變速箱油底殼，并將機電控制單元總成小心的拆下來，并斷開電磁閥連接的線板。首先利用萬用表對其N435電磁閥本身進行線圈阻值的獨立測試。

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.

通過萬用表的測量，N435電磁閥在不同溫度下的電阻也在正常范圍內，說明電磁閥本身是好的。然后將線板與變速箱控制單元的插頭拔掉，并把線板的另一端與電磁閥進行連接，從控制單元插頭出處找到N435電磁閥的相關針腳。直接從控制單元輸出端對電磁閥的電阻再次進行測量發現，電阻值變得無窮大，說明問題出在控制單元輸出端至電磁閥之間的線路上。如果電磁閥本身沒有問題，控制單元輸出端值電磁閥間的線路也沒有問題，說明問題在控制單元方面了。

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.

通過這種測量不難發現，問題出在線路板(因為控制單元輸出端至電磁閥間的線路連接直接隱藏在這個線路板里面)。因線路板電阻值的變化，控制單元到N345電磁閥的電流不能形成一個完整的回路，即使發動機沒有運轉，打開點火開關以后，車輛也會有個自檢，也會報有相應的故障碼，這也是為什么故障碼不能刪除的主要原因。

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.

奧迪Q5變速箱故障維修：

Troubleshooting of Audi Q5 transmission:

解決這個問題并不需要更換機電控制單元總成，只需要更換連接電磁閥的線路板就可以了。更換線路板后需要用專用診斷儀對變速箱進行引導功能的設定，并做離合器的自適應學習。除了更換線路板之外還有變速箱內外濾清器、油底墊以及專用變速箱油。引導匹配完畢后慧眾維修技師進行試車，確定換擋品質問題及故障是否已經排除。經過長時間的試車，確定故障沒有再出現以及沒有其他故障，此時故障徹底排除。

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.