TCU DSG7 DQ200

After the success of the DSG 6, a successor was inevitable. Having said that, a DSG 7 gearbox can’t really be called a successor. This newer DSG version uses a dry clutch and can handle a bit less torque than its older brother. So why did Volkswagen AG make this choice? The answer can be found in weight and resistance. With regard to the environment and fuel consumption, the DSG 7 is the better option, as long as it doesn’t require too much torque, that is.

Complaints and error codes

icon-fault-codesKnown complaints

  • The gear shift indicator (“PRNDS”) on the dashboard will flash
  • The gearbox does not shift
  • Short circuit: 30A fuse melted
  • Leakage and / or pressure loss

icon-check-markCan be remanufactured

OBD II VAG Description
P0562 VAG System voltage, voltage too low
16946 17099 Sensor / pressure switch transmission fluid pressure A, Unlikely signal
P0841 17225 Control module defective
P1604 8012 Hydraulic pump system, supply voltage too low
P177F - Hydraulic pump system, overload protection
P17BF - Functional limitation due to pressure drop
P1895 18303 Functional limitation due to insufficient pressure
P189C - No communication with TCM

icon-magnifierRemanufacture may be possible (additional diagnosis required)

OBD II VAG Description
P173A - Position sensor 1 for Gear Selector, unlikely signal
P173B - Position sensor 2 for Gear Selector, unlikely signal
P173C - Position sensor 3 for Gear Selector, unlikely signal
P173D - Position sensor 4 for Gear Selector, unlikely signal

Check the position sensors and the corresponding magnets for contamination by metal particles. If there is any contamination, check the gearbox thoroughly for mechanical wear/damage. Then clean the sensor and check that the error code is still present. If this is the case, then it is still plausible that the TCU is defective and needs to be remanufactured.


icon-check-markCan´t be remanufactured

OBD II VAG Description
P072A - Neutral not selectable
P072B - Reverse gear not selectable
P072C - 1st gear not selectable
P072D - 2nd gear not selectable
P072E - 3rd gear not selectable
P072F - 4th gear not selectable
P073A - 5th gear not selectable
P073B - 6th gear not selectable
P073C - 7th gear not selectable

Check the position sensors and the corresponding magnets for contamination by metal particles. If there is any contamination, check the gearbox thoroughly for mechanical wear/damage. Then clean the sensor and check that the error code is still present. If this is the case, then it is still plausible that the TCU is defective and needs to be remanufactured.

General operation DSG 7

dsg7-gearbox-display-uk

The DSG 7 gearbox is an automatic double clutch gearbox. DSG stands for “Direktschaltgetriebe” or “Direct Shift Gearbox” and the 7 indicates that there are seven forward gears. For this gearbox the designation ‘DQ200’ is also used. The Q (‘Quermotor’) indicates that this gearbox is used for transverse engines.

Mechanically, the DSG 7 gearbox can be described as a manual gearbox with two dry plate clutches, two drive shafts (input, primary) and three output shafts (secondary). An electronically controlled hydraulic control (Mechatronic) ensures that the gearbox can operate fully automatically. As an option, an additional manual shifting option can be selected (Tiptronic).

Automatic gearbox

A dual mass flywheel connects the crankshaft of the engine with the drive plate that rotates in line with the crankshaft. Two dry clutches on either side of the drive plate rotate independently of each other around the same shaft and each drives its own drive shaft by means of a ‘spline shaft’. Drive shaft 1 rotates inside the hollow drive shaft 2.On drive shaft 1 are the gears for 1st, 3rd, 5th and 7th gear. The gears for the 2nd, 4th, 6th and reverse gear are on drive shaft 2. From drive shaft 1, the gears for 1st and 3rd gear are driven on the first output shaft and the gears for 5th and 7th gear are driven on the second output shaft. From drive shaft 2, the gears for 2nd and 4th gear are driven on the first output shaft and the gears for 6th and reverse gear are driven on the second output shaft. Sprocket R1 on the second output shaft drives the third output shaft for reverse gear via sprocket R2. All three output shafts drive the differential gear.

dsg-7-scheme-uk

Because the gears for 1st, 3rd, 5th and 7th gear are on drive shaft 1 and the gears for 2nd, 4th, 6th gear on drive shaft 2, shifting takes place from one drive axle to the other when shifting to the next gear. The next gear is already engaged on the corresponding output (main) shaft. When shifting gears, the clutch to the drive shaft of the ‘old’ gear is decoupled in one smooth movement and the clutch to the drive shaft of the ‘new’ gear is coupled in one smooth movement. So there is an overlap in the drive through both gears. In addition, when shifting up, the engine torque is slightly lowered, while when shifting down, the engine torque is slightly increased. All in all, this ensures a fast and smooth shifting action with no noticeable interruption in propulsion.

The mechatronic in detail

dsg-7-mechatronic-uk

Actuator Function
N433 Shift valve for shifting 1st and 3rd gears
N434 Shift valve for shifting 5th and 7th gears
N435 Pressure control valve for clutch K1
N436 Pressure control valve for system pressure in gearbox half 1
N437 Shift valve for shifting 2nd and 4th gears
N438 Shift valve for shifting 6th and reverse gears
N439 Pressure control valve for clutch K2
N440 Pressure control valve for system pressure in gearbox half 2
V401 Hydraulic pump motor

Shifting, coupling and decoupling are controlled from the central gearbox control unit, the Mechatronic (J743). This consists of an electronic control device and an electro-hydraulic control unit. The Mechatronic is attached to the gearbox and has its own oil circuit, independent of that of the actual gearbox. This means that the hydraulic part of the DSG 7 DQ200 has its own oil pump, valves and cylinders. These cylinders are directly connected to the shift forks and the clutch levers.

The electro-hydraulic control unit incorporates an electrically driven V401 hydraulic pump and an oil pressure accumulator, which together ensure that the system pressure in the control unit remains between 40 and 60 bar.

The electro-hydraulic control unit has eight control valves. Valves N433, N434, N437 and N438 operate the shift forks that engage the gearwheels on the output shafts. Control valves N435 and N439 operate both clutches. Valves N436 and N440 regulate the required system pressures in both gearbox halves:

De TCU in detail

dsg-7-detail-uk
Sensor Function
G182 Speed sensor input shaft gearbox
G270 Pressure sensor for the hydraulic pressure of the gearbox
G487 Position detection sensor for the selector fork for 2nd and 4th gears
G488 Position detection sensor for the selector fork for 1st and 3rd gears
G489 Position recognition sensor for the shifting fork for 5th and 7th gears
G490 Position detection sensor for the selector fork for 6th and reverse gears
G510 Gearbox oil temperature sensor in the electronic control unit
G612 Speed sensor for drive shaft 2
G617 Clutch path sensor for clutch K1
G618 Clutch path sensor for clutch K2
G632 Speed sensor for drive shaft 1

In order to provide the Mechatronic with the necessary information, the TCU receives information from a number of sensors. The overview alongside shows exactly what information is received. Almost all of these sensors are built into the Mechatronic. However, speed sensor G182 is located outside the Mechatronic.

The TCU not only receives the necessary information from its own sensors but also exchanges information with the various measuring and control devices in the car via the CAN bus, for example:

  • E313-Gear selector lever
  • J104-ABS (with EDL) control device
  • J248-Control unit for diesel direct injection
  • J285-Control unit for display instrument panel
  • J453-Control unit for multifunction steering wheel
  • J519-Control unit for electrical installation
  • J527-Control unit for steering column electronics
  • J533-Diagnostic interface for data bus
  • J623-Engine control unit for diesel engines

Offer for remanufacture

Do you want to have a faulty DSG7 DQ200 remanufactured? Then enter “DSG 7” and the product will immediately appear on the screen.

Would you like more information about the remanufacturing solutions that ACtronics can offer, or can't you find your product on the website? Please contact us via info@actronics.co.uk or call our Customer Service: 01206 849920