Repair types

• Main pressure solenoid repair
• Cooling system solenoid repair
•  K1 and  K2 safety valves solenoid replacement  

Valve body solenoid fix  DQ250 02E 

 Audi A3, Q3, TT
SEAT Leon, Toledo
SKODA Octavia, Superb
VOLKSWAGEN Caddy, Beetle, Golf, Jetta, Passat, Scirocco, Shara, Touran

The six-speed automatic transmission DQ250 02E is a VAG company in-house development  together with BorgWarner Inc.
Wet double-clutch of the gearbox allows you to transfer torque to 350 H * m. The mechanical part of the gearbox is controlled via an electromechanical mechatronics unit. Mechatronics consists of an electronic control unit and an electrohydraulic unit equipped with sensors and solenoids.

Depending on the task being performed, the solenoids of gear shift, clutch and pressure adjustment are distinguished.

Solenoid N 217 is responsible for adjusting the pressure of the hydraulic fluid in the main flow of the valve bodyt. The pressure varies depending on the temperature, the speed of rotation and the operating mode of the automatic transmission. The electronic control unit periodically corrects the value of the main pressure in accordance with the operating conditions of the gearbox. If the primary pressure solenoid fails, the valvebody operation continues with the maximum hydraulic pressure. In this case, the gearshift is accompanied by thumps and jerks, which, in addition to reducing comfort, leads to premature wear of the clutch and gear shift .

Solenoid N 218 refers to the cooling system. The main reason for heating the oil in the automatic transmission is the operation of the clutches of the double clutch K1 and K2. When torque is transmitted between the clutch discs, friction occurs and, as a result, heat is generated. A special cooling circuit is used to cool the oil. Circulating the cooling circuit, the oil reduces the temperature and cools the clutch. Solenoid N 218 controls the cooling circuit .
In case  of improper operation of the solenoid, the oil temperature may rise above the permissible values ​​(135 degrees), which will negatively affect the operation of all the automatic transmission units (failure of clutches, electronic sensors, solenoids).

Also, when the oil overheats, the protection is triggered, which is expressed in the reduction of the engine torque or the complete opening of the couplings (no torque is transmitted to the box) - the vehicle stops completely. Overheating significantly shortens the service interval and requires a more frequent replacement of the hydraulic fluid.

To diagnose the solenoids, the specialists of the company Maktrans use modern equipment that allows you to repeat the work of the solenoid in the real conditions of the driving car.

The main cause of failure of solenoids is work in contaminated oil. Particles of chips and burnt oil form a finely dispersed suspension that clogs the oil channels. Getting on the rubbing parts, polluted elements cause premature damage and wear of the surface, incl. wear of the  solenoid bushing, which leads to jamming.

An example of a worn out bushing of a solenoid. The center hole of the bushing is worn .

To solve the problem, the specialists of the Maktranscompany  developed the technology of solenoid repair.
In the beginning, the solenoid is disassembled, using a special tool.

Further, the worn out bushing is removed and a new bushing made by the specialists of the company Maktans is installed in its place.

Manufacture of bushings is performed on modern CNC machines, which allows to comply with modern tolerances on the accuracy of the parts produced

After repair, the solenoids are retested for compliance with the operating parameters.

At the end of testing, the restored solenoid is installed in the valve body. Next, it is adapted and  the operation of the automatic transmission on road tests is checked.

The solenoids, restored by the technique of the Maktrans specialists, correspond to the performance of the original solenoids of the automatic transmission DQ250 02E. The service life after the regeneration is comparable with the life of new parts, at a much lower cost.

Electromagnetic valves of pressure regulators N215 and N216 are responsible for changing the oil pressure in the system responsible for the operation of the clutch. The solenoid N215 serves the clutch K1, and the solenoid N216 serves the K2 clutch. If the safety solenoid fails, the corresponding series of gears is disconnected:

- When disconnecting the first series of gears (K1), the car can only move in the second gear.
- If the second gear set (K2) is disconnected, the car can move on the first and third gears.

To determine the operability of the solenoids, Maktrans specialists use modern diagnostic equipment to accurately determine the presence of a malfunction.

This is the graph of the problem solenoid. Stepped areas indicate a solenoid valve stuck. Over time, such a solenoid can jam.

And this is the graph of the working solenoid .

To solve the problem with safety solenoids K1 and K2, the specialists of the Maktrans company recommend a replacement for new ones, with a guarantee of 1 year.