VAGCOM Adapter: The Ultimate Guide

Hello VAGCOM community,

Regarding adapters, there is now more information available in the diagnostic technical article, and also a (hopefully useful) universal version 2.2.
Since version 1.x of the economy version only works with higher-current COM ports due to the lack of output transistors, and most VAGCOM users likely work with relatively weak laptops, I didn't pursue that line of development further.

"Since I've recently received several direct messages regarding PCB layout:"
I'm unable to provide that because I lack the necessary expertise; I personally use universal circuit boards.
I would therefore appreciate it if you refrain from making any further inquiries.

Conversely, it might be a good idea if someone were to design an etching template that Rainer could make available on his website... ?

Ideally, this should happen after the then-current adapter version has been confirmed to provide stable operation in the majority of practice reports...


"@Rainer: I'd like to keep this thread at the top for about a week (hence the "Important" designation) and then change it back to its normal status, so that too many long-standing threads don't accumulate at the top of the forum."
If I forget, please turn off the "Important" flag (or another moderator can do it).

Okay .

I will probably be able to try out a CAD program (Ranger2) tonight and then post it here (let it be posted ).

Hi DaBibo,
If you have it or can handle it, use Eagle. It's probably more common than Ranger. The free version should be sufficient for the adapter.

Best regards, Rudi.

I just crashed, I was almost finished with the circuit diagram.

I find it easier to use features like the autorouter with Ranger.
I can try it, but it will be quite large due to all the resistors .

Hello.
Also ich hatten den Adapter Version 2.1 zusammen gelötet und VAG-COM hat den Adapter nicht gefunden. LED test was okay.
I used the components 1N4004, 2N3904, and PC 817 in the circuit. That should be correct. What did I do wrong?
The new version should fix that bug, and what function is the switch S1 supposed to perform? Regarding the trimpots, what would be an appropriate initial setting?

Best regards,
Nobody.

Niemand wrote:

Hello. Also ich hatten den Adapter Version 2.1 zusammen gelötet und VAG-COM hat den Adapter nicht gefunden. LED test was okay. I used the components 1N4004, 2N3904, and PC 817 in the circuit. That should be correct. What did I do wrong? The new version should fix that error, and what function is the switch S1 supposed to perform? Regarding the trimpots, what would be an appropriate initial setting?

Hi.

What are the results of the dry function test (function check without a computer, as described in the diagnostic article, with S1 open)?

S1 is designed to bring the adapter functionally closer to the Noxon minimal model.
As a starting position, I would place the pieces in their central positions.


@everyone:
My computer has been acting up lately (it often forgets the BIOS despite having a fully charged battery, etc.).
If I don't participate in the forum for a while, it is most likely due to .

Hi,
Here's a case report:
I assembled version 2.2.
Er besteht die Trockentests, ich kann aber in meinem Fahrzeug nur 03-ABS ansprechen (Fehlerspeicher, keine Blöcke wg. Shareware).
"When I try to access the more important engine control unit (01), it says 'cannot synchronize baud rate'."
Ulf already reported about that in version 2.0.
Vehicle: Audi 100, year 1992, 2.5L engine (AAT). Computer: Dell laptop, 266 MHz.
What baud rates does VAG-Com actually test? Could it help in manually setting an incorrect initial value?
Where in the facility should I take measurements and, if necessary, adjust settings to meet target values?

Okay, I manually traced the circuit and etched it onto a PCB. If Da Bibo's software keeps crashing, I could also redraw it properly in CAD and share it.

Christian.

christians wrote:

Hi, Here's a case report: I assembled version 2.2. Er besteht die Trockentests, ich kann aber in meinem Fahrzeug nur 03-ABS ansprechen (Fehlerspeicher, keine Blöcke wg. Shareware). "When I try to access the more important engine control unit (01), it says 'cannot synchronize baud rate'." Ulf (?) has already reported on this from version 2.0.

Hi Christian,

"Yes, that's correct, but since I changed R 10 and 11 to 1 kOhm each and R 9 to 3.3 kOhm (without VR 1 in series / part numbers referring to plan 2.2), my adapter has been communicating stably with the motor and ABS."

I'm hesitant to address the airbags because of a potential risk of "tipping over" the control unit software (a warning message in VAGCOM), and I had simply forgotten about the Winged Functional System (WFS) so far.

I bought the "bargain" laptop from Elitegroup for €777.

Quote:

Where in the facility would I need to take measurements and, if necessary, adjust settings to meet target values?

Perhaps at the collector of transistor T3 (using an oscilloscope!).
The voltage there should switch rapidly and clearly between approximately 0.3 and 12 volts.
Here, "fast" means having the same slew rate as the K-line when communicating with the ABS (Anti-lock Braking System).
Ideally, the K-line and the collector of the T3 should be represented using two separate channels.

Compare the signal waveforms at the collector of transistor T3 during communication with the ABS system and during the attempt to communicate with the engine control unit. Then, use potentiometers VR1 and VR2 to optimize the signal waveform at the collector of transistor T3.
Good luck .

If you can't find an oscilloscope: Too bad .

Thank you for the new schematic diagram, version 2.2.
'It flawlessly recognizes the airbag and ABS controllers on a T4 4/95 (70XOC) (airbag error produced, successfully reset), with completely non-critical VR1/VR2 values. The same applies to a Polo 6N 12/94 AEF, where all possible VAG COM functions work immediately: diesel pump (41), actuator (03), measurement block 01. Everything works perfectly from the start.'
At Reichelt, only the 2x and 4x models are available: PC 829/849 Sharp.

Excellent: The LED test using VAG-COM under 'Options' should be mentioned in the description, as it clearly reveals any errors in the LED system. LEDs 1 & 2 are also tested without power supply.
I initially considered the VCC LED to be unnecessary, but since I learned that LEDs 1 & 2 (which I replaced with super-bright SLH56 LEDs - a deviation from the original schematic) also light up without VCC, simply through the COM port, it's often easy to miss that the power supply is missing in a hectic situation.

'Everything was tested using an old Compaq Armada and an HP Omnibook 2100. Everything is housed in a test fixture enclosure (Bopla, where the test fixture end can be used as strain relief) and connectors are built using sockets (which are often found on scrap electronics) with solder pins as contacts. It's now available at Elektor Krüger in Hanover for 12.50€ including shipping.'
The connectors for the K&L Line can be found in older Polo models within the central electrical system, where they are connected to brown/red wires. The data connector fits perfectly, but you have to force it into the VCC socket.

A request to the layout designers: Please use a 4-way OK PC 849 pinout as your basis.
http://www.sharp.co.jp/ecg/opto/products/pdf/en/oed/photocouplers/pc829_e.pdf

Thank you again, Kai, who no longer has any 1KS.

PS. Opel software at a VAG-Com price would also be interesting; is there anything like that available?

I'm also interested in Opel, as my wife unfortunately still drives one of those cars and will have to for a while! Is there anything decent and comparable available? I know it's off-topic, so please don't get too upset about it!

Hi,
Thank you for the response.
I'm going to borrow an Oscar from the company next week.
Once I've hopefully learned a bit more, I'll follow up with a report.
Christian.

To risk stating the obvious:
I have just "discovered" http://e-www.motorola.com/brdata/PDFDB/docs/MC33199.pdf an IC for converting K/L to serial.
At first glance, it looks like a good fit.

Best regards, Christian.

christians wrote:

To risk stating the obvious: I have just "discovered" http://e-www.motorola.com/brdata/PDFDB/docs/MC33199.pdf an IC for converting K/L to serial. At first glance, it looks like a good fit.

Hi Christian,

An interesting link regarding hardware.

I also had the idea of replacing the discrete transistor stages with comparator ICs (like in the Motorola chip) .

Why all the effort?
Today I tested your 2.2 on a first-generation Golf TDI (manufactured in April 1994). It worked perfectly without any issues. Interestingly, there was no ground connection wired to the OBD socket in this vehicle. However, that doesn't matter to me, as I get the power supply from the cigarette lighter socket, which saves me from having problems with the small connector pair of the old OBD version.
But unlike the original design, your circuit works perfectly without any problems, and you can actually obtain all the necessary components for it, which I doubt is the case with the Motorola version. And – more parts mean more potential errors during assembly.

Best regards,
Kai

discreet rules.

Post-Polo AEF.

"Why all this effort?"
Because version 2.2 still doesn't work everywhere, despite all the time that has already been invested in it.
The IC doesn't require much "accessories". Therefore, it would ideally involve fewer rather than more parts. The challenge is indeed the sourcing: so far, I've only found a supplier with a minimum order quantity of 55 units and a delivery time of 6 weeks (!). However, they are relatively inexpensive at just €1.50 each.
Christian.