Vag-Com and 11/93 1Z

Hello everyone...

'I'm having the following problem: VCDS (Vag-Com) isn't working properly with my Audi 80 1.9 TDI with engine code 1Z (manufactured in 11/93). I repeatedly get the error message 'Unable to synchronize baud rate,' especially when I try to access the engine control module (ECM). However, I can read the ABS control module and the airbag control module without any issues. Is there any hope of resolving this?' If the synchronization with the other ECUs is working, is there a way for me to also read out the main ECU?
I have already reviewed the known issues with VCDS and, with regard to synchronization problems, I have also tried the suggested solutions - unfortunately, without success...

It would be helpful to know which interface adapter you are using, Ulfs (version?), Maiks, eBay, etc.?

I am using an adapter from a user in the audi4ever community.

Then you should probably contact them... they'll know what's going on (hopefully).

Otherwise: Search function.

I can only say it 1000 times .

The search function finds the following: /viewtopic.php?t=1721&highlight=baudrate+1z

Oh my goodness...

I'll give it a try.
Sorry.

@edward

In addition to the problems already discussed in the forum regarding my 1Z, I also experienced the following.
I changed the following settings using VCDS, and it works reliably now!

char_int set to 0. kw2_delay set to 10. baud rate set to 9600.
Setting the baud rate to 4800 and 1200 could also be helpful.

Try it out! I'd like to know if this works for me, or if it helps others as well.

@joergs:
No, unfortunately, it's not working with your settings either.
However, I now at least have one clue: with a baud rate of 240 (yes, 240, not 2400), I can at least access the M-STG and read block 000, but I can't access block 007 at all - I haven't fully understood it yet, but I'll keep experimenting...

@edward

What version of VCDS do you have? I had problems with version 2.082, but it's working stably now. Also, does the adapter work with other vehicles?

joergs wrote:

I had problems with version 2.082, but it's stable now!

Hi Jörg,

How did you manage to do that?
Again with different protocol settings?

@ulf

The magic word was 'blk_int' set gradually downwards! And lo and behold, the airbag control unit works, and so does the ABS. No interruptions and no communication errors! Additionally, I had tried to give the VAG-COM process itself a high priority. It also worked, but it wasn't necessary at all!

hello Edward

For older control units, you can only access measurement block 000.
read out.


Hi Huby.

@joergs:
Okay, I also have the 208.2. On other vehicles (e.g., a 1998 A4), it works with the basic settings. As I said, I can now finally read block 000 of the M-STG with a baud rate of 240, but with this setting, I can't access any other STGs. I have to reset the start baud rate to 0 again. Do you think lowering the `blk_int` value would help? What steps did you take to try it? And at what value did it then work flawlessly?

@huby:
Oh really? Hmm... Actually, that would be enough for me for now, because I could at least see if, for example, my needle lift sensor is working by checking Field 2 from Block 000 (which shows the intended injection start), right? I was just about to record a log to check this – it supposedly worked, but the log file only contains the initial information lines and no actual read values. What could that be?

@all:
Also, another thing: the part number that my VCDS (Vag-Com) software displays for my control module seems to have absolutely nothing to do with the actual control module number. It says 8a0907401B, but shouldn't it actually be 028906021???

@edward

Okay, whether you need to adjust the settings higher or lower depends on many factors (computer, device, adapter, etc.). You'll have to experiment to find the right settings. I'm currently using a value of 55 for 'blk_int,' and I tried different values in increments of 15.

I can imagine that you might be having an adapter problem. I've definitely built about four of them that worked everywhere except on my vape! It was frustrating!

What kind of laptop do you have? Which operating system? What other processes are running? Try to close any unnecessary processes. Also, when troubleshooting problems like this, it's often recommended to use a baud rate of 9600! Did you enter 0 or 00? 00 should be the default value! As I see it, you also have a first-generation control unit installed, which has known communication issues.

By the way, VAG-COM runs on a 486 DX2 with 4 MB of RAM and an early version of Windows 95! If it works with that, it should work with everything else!

'However, the part number you provided should be correct: 8A0 907 401 B. This should be the original VW/Audi part number.'

@joergs:
Okay, so I have an old Toshiba Satellite Pro with a Pentium I processor running at 90 MHz, 8MB of RAM, and Windows 95 as the operating system. I've actually stopped all the processes that were running in the background. No improvement.
It seems I'm slowly getting a handle on everything bit by bit: I just want to be able to record one log file, and then I'll be satisfied for now :-).

joergs wrote:

The magic word was "blk_int" gradually reduced! And behold, the airbag control unit works, and the ABS also works, without any problems! No interruptions and no communication errors! Additionally, I had tried to give the VAG-COM itself a high priority as a process. It also worked, but it wasn't necessary at all!!!!!!!!!!!!!!!!!!!!!!!!!!!

Hi Jörg,

Nicely figured out .

@Rainer:

Wouldn't that be worth a mention in a diagnostic article (if you get the chance )?

@edward

What problem do you still have now? What works now, and what still doesn't work? So, the notebook should be sufficient. If it runs on a 486, then it should run on this as well!
'But what I'm not entirely ruling out is what was mentioned earlier, that perhaps only group 000 can be read. What happens if you select group 004? Does it show 'ERROR' in the fields? That's what happens with my control unit as well, with groups above 015!'
Do you ever get an error message like 'can't sync baudrate' or 'too many communication errors' when the communication is running?
Perhaps a schematic diagram of your adapter would be interesting to see!

@ulf
'This might, as we discussed before, indicate a potentially insufficient flank steepness and slew rates! This could mean that the synchronization and timing of VAG-COM become even more confused, and my approach of modifying the communication parameters might no longer work, because the shift in synchronization and timing is logically only possible within certain limits! What do you think?'