VAG-COM Issues: Audi A4 Troubleshooting Guide

Hello,

I'm currently having a small problem reading the diagnostic trouble codes on an A4 from the year 2000. I have the full version of VAG-Com. However, I can't connect to any of the control units in the A4. It always says "No connection!" All other vehicles, like A6s, work fine. I've tried several different vehicles as a test. I think it might be related to a setting within the program. Since I don't have much experience with these types of programs, I was hoping someone here could tell me what might be wrong. Thanks.

luiggi wrote:

I have a full version of VAG-Com

.
Please provide the text you would like me to translate from German to English. I will then give you only the translation, without any explanations.

What does the LED on the diagnostic connector indicate?

Have you ever measured the voltage on the diagnostic connector pins of the A4? Is there at least power reaching it, or was the diagnostic fuse perhaps used as a "perfect replacement fuse in case of a breakdown"?

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It can also be used as a verb, meaning "to gust."

Hello,

Version is 908, so it's the latest version. The LEDs on the interfaces are constantly green. The vehicle is definitely in good condition, as it was recently at an Audi dealership, where they were able to read the error memory without any problems. So, the fuses, etc., are fine. It's almost certainly a setting within the software. It tries to establish a connection and then displays "NO RESPONSE FROM THE CONTROL UNIT." This happens everywhere, whether it's the engine electronics, ABS, or anything else.
What could possibly be wrong?

Quote:

Please post the exact version.

Please send me the serial number of the diagnostic cable via private message.

Was there any water ingress in the vehicle? I once had a similar issue with a 7M where the K-line was soaked, and none of the control units were responding.

No. As I mentioned, the vehicle was probably scanned with a diagnostic tool at Audi just 3 hours ago, so it was working there. However, I want to use VAG-COM to access the ABS control unit and check the individual sensor readings, because the ABS seems to engage too early at low speeds. Best regards.

Hello Luiggi,

I certainly didn't intend to discredit VAG-COM / VCDS with my question, but please understand that I cannot provide support for diagnostic hardware from third-party providers.

The hardware serial number you mentioned identifies your diagnostic cable as "Not Ross-Tech" and also as "Not a diesel mechanic."

Back to the topic: If you use a diagnostic system from http://shop.dieselschrauber.de/, will it also work for diagnosing an Audi A4?
In your case, please ask the vendor of your system what might be wrong.

Best regards, Rainer.

Hi Rainer,

"I bought the VAG Com many years ago from PCI-Tuning. I didn't even think about it being a competing product to Dieselschrauber. However, since I've received a lot of help in this forum, I posted my question here. But I will contact the technical hotline at PCI. It just surprises me that this problem only occurs with that specific A4 model. Otherwise, I've been using the tool for several years and on probably hundreds of vehicles. So Rainer, and others here, thank you anyway for your support."

Hello Luiggi,

Oh, then I must have misread it. I saw "AVG," which definitely isn't really suitable.
If your diagnostic hardware is from Ross-Tech, specifically the same as the KEY-USB, HEX-USB, or HEX-USB+CAN, then there should be no issues.

Possible causes of the problem:
- Du verwendest einen RS232 auf USB Schnittstellenadapter. That's not going to work.
- The A4 is a vehicle from a specific supplier that installs "third-party radios," but unfortunately, they don't really pay attention to the pin configuration of the radio DIN connector. I've had cars from this supplier before. The same applies to radios that are installed by the owner themselves.

However, there's a counterargument: the workshop was able to access the vehicle's data.

Best regards, Rainer.