DQ200: A grown-up "robot"Valentin Romanov
The DQ200 seven-speed "robot" having the code in the 0AM spare parts catalogues was developed for the mass models of Volkswagen. The first DSG which was produced since the end of 2002, the six-speed DQ250, was designed for considerably powerful engines with a torque of up to 350 Nm. The next, seven-speed transmission was designed for engines with a displacement of no more than 1.8-2.0 l and a torque of up to 250 Nm. Production of the DQ200 began in November 2007 at the Volkswagen plant in Kassel (the same place where the DQ200 was produced), and it became the most compact and light of all DSG transmissions. Its weight is 70 kg, 23 kg less than the six-speed version. The dry clutch design has been chosen precisely for a lighter weight of the unit.
The DQ200 is installed on a wide variety of models produced by the Volkswagen group, such as Volkswagen Golf, Polo, Passat and others, Skoda Fabia, Octavia, Superb and Yeti, Audi A1, A3 and Q3, as well as on Spanish SEAT cars that are rare in Russia.
The operating principle of the "robot" with a dual clutch
In one basket, two clutch discs are combined: K1 (1/3/5/7 gears) and K2 (2/4/6/R gears). The clutch is normally open. At the moment when it is necessary to close the clutch, the mechatronics unit rod pushes on the clutch withdrawal fork, which presses on the throwout bearing, and the latter already acts on the basket “petals”, which leads to closure of the driving disc and one of the driven ones. The mechatronics unit 0820 consisting of the electronic control unit and the hydraulic circuit 0829 with a pump, in turn, controls both clutch release and gear engagement.
The undoubted advantage of the gearbox with two clutches is its speed. The gear is initially engaged, and at the moment of shifting it is enough to transmit the engine torque to another clutch disc. As a result, the user gets an automatic gearbox with the same high efficiency as a manual gearbox has. It shifts gears faster than any driver does, and as a result, the change of speeds occurs almost without breaking the power flow. However, in reality these undoubted benefits are sometimes combined with problems.
Frequent clutch failures
In the early years after its release, the DQ200 0AM system received a lot of reliability complaints. The reason seemingly was that it was the first such transmission with a dry clutch. It was smaller and lighter than the first DSG, the DQ250 wet clutch, but worked in more difficult conditions. For eliminating reliability problems, the transmission was repeatedly updated and even the model code was changed to 0CW. The efforts of the designers were not in vain: the unit has become more reliable, although many of these boxes now require repair simply because of their service life. This certainly upsets car owners, but creates new jobs in technical centers engaged in repairing automatic transmissions.
The clutch itself is reliable enough. However, in the urban cycle, wear due to frequent switching between clutch discs occurs several times faster compared to manual and classic automatic gearboxes.
The main signs of DSG failures:
- vibrations under load in a certain range of gears;
- rigid inclusion of D and R modes;
- skidding while driving in one of the gears under load;
- the car stalls when the engine is started or when D or R mode is turned on;
- appearance of error indications on the dashboard.
A clutch of this type is not repairable by default. In case of a malfunction of such a clutch, it must be replaced as an assembly. Along with the original unit from Volkswagen, you can use the kits from the LuK and Sachs brands, the cost of which is lower. 0845, 0847, 0848, 0849 We prefer the LuK brand, since Schaeffler which owns this manufacturer supplies such clutches for Volkswagen as well. In fact, these are the same original clutches, but from a different source. In terms of quality and performance, they are exactly the same.
While installing the clutch, it must be adjusted with a special tool. Clearances of the friction discs are adjusted using the washers supplied with the clutch. The tolerances are indicated on the new clutch basket.
Since 2012, Volkswagen has been using new type transmissions that differ from the previous ones in a number of aspects, including the clutch. The clutch release bearing, clutch release fork and clutch basket were redesigned. The reinforcing ring that was installed on the clutch basket “petals” is no longer used: its functions are performed by the clutch “petals” themselves. The new clutch has a different friction disc that wears out evenly and lasts longer than the old one. Note that the new clutch is not interchangeable with the previous one.
Problems with the mechatronics unit
Most of the problems arise with the mechatronics unit that controls the process of gear shifting and clutch release. Malfunctions of the mechatronics unit can affect not only the gear shifting process itself, but also wearing of the dual clutch and other mechanical parts of the gearbox. A frequent malfunction of this unit is a crack in the hydraulic part 0817-0829, which causes a loss of pressure in the mechatronics circuit. The pressure drops, and the electronic unit upon receiving information about this from the sensor gives the command to the hydraulic pump to switch on for restoring the required level. If the leak through the crack continues, the pump switches on more and more frequently and finally begins to work constantly. For this reason, the working fluid leaks through the breather, which leads to a decrease of the fluid level. Signs of this malfunction:
- the car is not moving;
- knocks are heard when shifting gears;
- an error indication lights up on the dashboard.
For such cases, there are the following repair methods: replacing the hydraulic plate with a new or reworked one, or installing a repair kit for the hydraulic plate.
The mechatronics unit DQ200
Due to a constant operation of the pump, overheating occurs, which frequently leads to short circuits between the conductive paths inside the board. As a result, the electronic board of the mechatronics control unit fails.0831
Of course, the reasons for the board malfunction may be different. For example, it can be a breakdown or a short circuit of any components on the board itself. Signs of the malfunction:
- occurrence of an error indication;
- the car is not moving;
- loss of communication with the control unit.
There are cases when a fault icon appears on the dashboard and the diagnostic equipment shows a mechatronics error. At the same time, the transmission seems to be working normally and there are no visible failures. But it is still not worth to delay repair. In case of delay, there is a risk of damaging the clutch.
Another frequent problem is leaking of mechatronics fluid through the cuffs of the clutch release rods. This is dangerous because the fluid can get on the clutch friction discs and cause their skidding. As a result, you will have to replace the clutch. For eliminating such a leak, you will need a repair kit for the clutch rods (cuffs), or you will have to replace the rods assembled with the cuffs. Note that after switching to the new type clutch (since 2012) the length of the rods has changed. Using a different size of the rod will lead to incorrect reading of the clutch clearances, about which the computer will notify you with an error message on the dashboard.Еще одна частая проблема – течь жидкости мехатроника через манжеты штоков выжима сцепления. Это опасно тем, что жидкость может попасть на фрикционные диски сцепления и привести к их пробуксовке. В дальнейшем придется менять сцепление. Для ликвидации течи понадобится ремкомплект штоков сцепления (манжеты) либо придется менять штоки в сборе с манжетами. Учтите, что после перехода на сцепление нового образца (с 2012 года) длина штоков изменилась. Использование штока иного размера приводит к неверному считыванию зазоров сцепления, о чем компьютер уведомит сообщением об ошибке на панели приборов.
The mechanical portion
Sometimes malfunctions of various bearings occur, which mainly take place due to a decrease in the oil level as a result of leakage through one of the seals and manifest themselves as noises. A breakdown of the pilot bearing of the fork of the 6th gear and reverse gear also occurs, as a result of which the mechatronics unit does not switch these gears. 0853 It is possible to eliminate such a breakdown only by completely disassembling the gearbox and replacing the damaged elements with new ones.
When working with DSG transmissions, we use the ODIS Service scanner that delivers the fastest and most informative results. It is used by official dealers of all brands of the Volkswagen group, since it gives information on "dealer" ways to troubleshoot a transmission malfunction and provides diagrams for installing and dismantling individual elements, and all fault codes are decoded correctly, unlike the readings of some third-party scanners. The ODIS Service provides a wide data stream that enables to evaluate the transmission performance and identify the fault.
It is possible to identify a particular clutch malfunction not only using the fault codes in the gearbox control unit, but also by evaluating the current data on the clearances, as well as via visual inspection through the viewing window located at the top of the bell. It is also possible to assess the state of the mechatronics unit by viewing the current data on pressure and an external check for leaks. Diagnostics of the mechanical portion is carried out by the method of visual assessment of its condition, as well as by checking the oil level, the operability of the forks (while dismantling the mechatronics unit) and the presence of noises from the transmission on the lift device. The cause of problems may be not a single fault, so we generally check all the assemblies sequentially.
For repairing this transmission, you must have a mounting kit for the dual clutch, special tools for disassembling the housing, an accessory for pressing out the clutch forks, and guides for installing the mechatronics unit.
How to increase the resource
DSG repairs are not cheap, and for preventing them we recommend that customers perform the proper electronic diagnostics every six months of operation. Oil manufacturers do not require oil replacement, but we consider it necessary, as the maximum oil service life in our conditions corresponds to 70 thousand km of run. To reduce the number of gear changes during constant operation in urban traffic jams, it is advisable to use manual mode: if you set the selector to the position for manual switching, the gearbox will not constantly switch from the first gear to the second one and vice versa at low speeds and this will reduce wear of both the clutch and the switching drive. Furthermore, for stopping it will be necessary to use only pressing the brake all the way, at which the gearbox simply opens the clutch leaving the first gear engaged. The transmissions produced after 2014 use a new software that prevents excessive shifts.
Text and photo by: Valentin Romanov, Alexander Zhikharev