Vag-com is still not working properly

hi

I'm having a small problem with VCDS (VAG-COM). I've read through some threads, but I haven't found exactly what I'm looking for.
Okay, I have an Audi 80 (1Z), and I'm using Maik's diagnostic tool, but I just can't seem to connect to the engine control unit.
I can access the ABS control unit, but when I try to access the engine control unit, I always get an error message saying something like "cannot synchronize baud rate" or similar.
What seems strange to me is that the +12V wasn't present at the 2x2 diagnostic connector, and I had to take it directly from the battery. I tried it on an A4 size paper, and it worked.
I read something earlier about bringing "potis" into the middle position. It probably refers to the two components that have a screw attached. Now, does "middle position" refer to the position of the screw, or to the value? If it's about the value, someone would need to tell me how to measure that. I have a measuring device for it.

Maybe someone can help me.

Best regards.

thomas

thom wrote:

I'm having a small problem with VAG-COM. I've read through some threads, but I haven't found what I'm looking for. Okay, I have an Audi 80 (1Z),

Hi Thomas,

Have you also read the diagnostic article, specifically the section on VAGCOM bugs?

If you can't reach the engine, it seems to be the well-known problem that Jörg's solution addresses .

I tried it today, but unfortunately without success. The same problem as before: ABS is not working, MSTG is still not working, and I'm getting the same error message: "CANNOT SYNCHRONIZE BAUD RATE."
It might be due to the laptop itself, considering it has a Pentium 300 processor with 16 MB of RAM and Windows 98.
where is the +12v line from the diagnostic connector actually protected, or does it not matter if the +12v flows from the battery first or from there? Is there also a fuse in the control unit that might have blown?
This is a 1993 Audi 80 (B4) with a 1Z engine.

Best regards.

thomas

thom wrote:

I tried it today, but unfortunately without success. It's the same as before: ABS works, MSTG works, but it still doesn't work, and I'm getting the same error message: "CANNOT SYNCHRONIZE BAUD RATE". Could it possibly be due to the laptop, which has a Pentium 300 with 16 MB of RAM and Windows 98

?
Hi Thomas.
I'm also familiar with that error message from my adapters. Try adjusting the potentiometers on the adapter; maybe that will work (along with the settings in the VAGCOM options).

Quote:

Where is the +12V line from the diagnostic connector actually protected, or does it not matter whether the +12V flows from the battery first or from there?

Without 12 volts, you wouldn't be able to activate the ABS or other systems, so it's probably not the issue.

Quote:

There might also be a fuse in the control unit that could have blown.

I don't know.

You just needed to increase the start baud rate from 0 to 240, and then it would work.

Thank you, Ulf, for your tips.

Best regards.

thomas

Hi!

I'm having a similar problem, but I didn't want to start a new thread.
T4 with AJT engine, and VAG-COM is not working.
No connection, absolutely nothing.

The laptop and adapter have been tested on various VW and Audi vehicles.

Could it really be that there's a cable break somewhere in the data line?
(It's a 2000 model, only 70,000 km on the clock, nothing has been done to it yet, but now the mass airflow sensor is broken.)

kunbela wrote:

Could it really be that there's a cable break somewhere in the data line?

Hi.
While it might not be a common mistake, it certainly could happen... "Nothing is impossible!"
Measure the voltage between pin K and ground when the ignition is on, without using an adapter.

I'll do it tomorrow.
Today, I tried contacting Bosch Service. He was also unable to establish a connection, despite using the original equipment.

Where can I find the data cable directly connected to the control unit?

Hello!

I'm having a problem where I can no longer access the engine control unit (ECU) with the engine running. If the engine isn't running, it works.

Do you have any tips?

Turn off the engine, log in to the control unit, and then restart the engine!

Hi,

onclebenz wrote:

Hello! I'm having a problem where I can no longer access the engine control unit (ECU) with the engine running. If the engine isn't running, it works. Do you have a tip?

Which VAG-COM version and hardware are you using?

Best regards, Rainer.

If an aftermarket radio is installed, it's best to completely turn it off or disconnect it.
I once had a similar problem where I couldn't access the control unit anymore.