0B5 (DL501) - 7-speed automatic transmission with dual wet clutch. Appeared in 2008 on the Audi Q5 , is a logical development of the 02E and 0AM boxes (an article about repairing the 0AM mechatronics can be read here )

The transmission is designed to transmit high torque (up to 550 Nm at 9000 rpm) and is coupled with engines with a capacity of 2 liters or more.

As with all VAG DSG boxes, there are 2 weak points here, these are the dual clutch and mechatronics. Of course, the engineers took into account the experience of previous developments, some units have been significantly modernized or, on the contrary, simplified in order to increase reliability, but with a mileage of > 100 thousand km. problems still begin.

In mechatronics there is a separate solenoid that provides lubrication and cooling of the clutch, one of the most heavily loaded, if it starts to jam - the clutch overheats, the temperature can reach 160 °C and the friction material begins to break down, contaminating the oil.

Dirty oil begins to "kill" other solenoids, in particular the solenoids that control the clutch, and this already leads to noticeable consequences for the driver - shocks appear when switching gears, the intensity of which constantly increases.

In this article we will tell you how Maktrans specialists restore 0B5 mechatronics.

A bit of theory. The mechatronics in DSG boxes is the real brain and control center of the entire transmission. If in a conventional hydraulic automatic transmission you can separate such concepts as a valve body, wiring, oil pump, ECU (electronic control unit), then the mechatronics combines all these units.

If we consider the DL501 mechatronics specifically, it includes a hydraulic system control unit, an electronic control unit, sensors and actuators, with the help of which gears are switched in the mechanical part of the box.

Mechatronics functions:

1. Adaptation of pressure in the hydraulic system
2. Adjusting the operation of the double wet clutch
3. Adjusting the clutch cooling system
4. Selecting the gear shift moment
5. Controlling the gear shifting process
6. Communication and collaboration with other control units (mainly synchronization with the engine control unit)
7. Emergency Operation Program
8. Self-diagnosis

We start diagnosing mechatronics. We removed it from Audi Q5, symptoms - kicks when switching, adaptation procedure did not help.

Typically, such symptoms are accompanied by the following errors:

• P17D800 - Torque limitation due to clutch temperature
• 022FE - this error indicates clutch slippage, usually appears when the solenoid can no longer provide sufficient pressure to compress the friction in the clutch drum, or the wear of the discs is critical

You need to be extremely careful when removing the cables, you can easily damage them. Wiring 0B5 often fails due to overheating, we will tell you how we diagnose it further.

Let's start to disassemble

We disconnect the connectors and take the cables to the sink

Checking and repairing solenoids

We can proceed to checking the solenoids. We will diagnose on a special stand, the principle is as follows. The solenoid is installed in the stand through a suitable adapter, the oil pump creates the necessary pressure of the transmission fluid and the electronics of the stand gives control commands and reads the parameters at the "output", based on the readings, a graph is drawn. From the graph, we understand how the plunger inside the solenoid works, steps and dips will indicate that the plunger is stuck in the guide bushings, this happens if dirty oil has disrupted the geometry of the working surfaces.

We remove the cooling solenoid and install it in the test stand

The graph is normal (in the photo below - on the left), on the right you can see the graph of the solenoid with critical wear and understand the difference

Testing the clutch solenoid

Clutch Solenoid Operation Schedule

Here you can see the problem, this solenoid was giving shocks when changing gears. Below you can see the solenoid disassembled. The core works on the guide bushings, because of the abrasive in the oil on the inner surface of the bushing there is wear and tear and it can no longer center the plunger, distortions occur.

We offer 2 options for solving the problem, repair and replacement of the solenoid with a new one, manufactured by Borg Warner . Repair consists of replacing the bushings with new ones, a special device is used to replace them.

New bushing

Some electromagnetic valves in mechatronics do not wear out, since they are not so loaded, we check them for breakage. We ring them with a multimeter in the resistance measurement mode.

We install tested and restored solenoids in mechatronics

Checking and repairing mechatronics wiring

It's time to check the wiring for breaks. In 70% of cases, damage to the cables can be fixed by our technicians by soldering the tracks, but in case of critical damage, it may be necessary to replace the wiring with a new one, we can offer 2 options, the original VAG and Chinese wiring:

• Automatic transmission internal wiring kit 0B5 09-up 0B5398009E 0B5927807C 0B5398008 0B5398009D - original, $280
• Internal wiring with speed and temperature sensor automatic transmission 0B5 09-up 0B5927807 - not original 80$

We ring the cables with a multimeter, first installing a technical plug that will close the necessary contacts

That's basically it, mechatronics repair consists of checking solenoids and wiring and working on their restoration. Unlike 0AM, there is no hydraulic accumulator and pump (the pump is located separately). There are problems with the electronic control unit, it cannot be restored and is simply replaced:

• Electronic control unit (TCU) automatic transmission 0B5 DL501 07-up 0B5927156E Used

Double "wet" clutch

Dual Clutch Design

The dual clutch performs 2 functions:

• transfer of torque when starting and torque cut-off when stopping;
• gear engagement (odd gears (1, 3, 5, 7) are engaged via primary shaft 1 via package K1, even gears (2, 4, 6) and reverse gear are engaged via primary shaft 2 via package K2)

As we have already said, a malfunction of the solenoids (in particular the clutch cooling solenoid) leads to overheating of the clutch, and this destroys the friction discs and Teflon rings.

For the driver, this is expressed in the following symptoms:

Mechatronics repair is often associated with clutch repair, we offer 2 options, repair or installation of a new clutch . For clutch repair we use friction discs manufactured by the American company Borg Warner and Teflon rings Transtec . There is already a restored clutch on sale, sold on condition of exchange for your faulty one, price $ 550 , 1 year warranty.

After assembling the mechatronics, it can be installed on the car and adapted. Such repairs cost $750, the Maktrans company provides a 1-year warranty with no mileage limitation.

If you do the repairs yourself, we have any spare parts and oils for 0B5:

• Steel wheels 0B5
• Friction discs 0B5
• Pumps, shafts, solenoids, etc. 0B5
• Gaskets 0B5
• Filters 0B5
• Transmission oil FOSSER DSG Fluid 1 l. - for mechatronics and clutch
• Transmission oil FUCHS TITAN SINTOPOID SAE 75W90 1 l. - for mechanical part