Notice the top left corner shows "Protocol: UDS" and there are some functions that are simply not available like Measuring Blocks (since there are no longer any measuring block numbers). This is a colossal PITA for scan tool manufacturers like us since we need to maintain special files for every type of control module.Īnyway, on to practical matters, this is what it looks like when you are communicating with a control module that uses UDS:
![what is vcds what is vcds](https://dn-mdpic.qbox.me/pic/201310/01/zipHjNHCJXnlqmG_272549787.png)
#WHAT IS VCDS CODE#
So now when you get a fault code there is no way to know what it means unless you have a special translation file UNIQUE TO THAT SPECIFIC TYPE OF CONTROLLER.
#WHAT IS VCDS SOFTWARE#
In theory this could have resulted in our software being really useful (beyond just Generic OBD-2) on other brands, right? Wrong! What the ISO 15765 ( UDS) did instead was to put in an extra layer of translation that was needed to interpret fault codes, measuring data, etc. My understanding is that the big European automakers, along with their suppliers, decided to get together on some common diagnostic "language" that would reduce differences for example, in what Bosch would need to do for control modules going into Volkswagens compared to the same type of modules going into Mercedes. The scan tool didn't need to know anything about the type of car in order to give you the fault code meaning. In a 2006 Audi A8L, the same fault would have the same meaning. For example, in a 1993 Golf 2.0 ABA, if you got a fault 00532, VCDS would interpret that as "Supply Voltage B+: Signal too Low" or something like that. Before UDS ("Unified Diagnostic Services"), Measuring Blocks used somewhat standardized numbers (like group 115 shows requested and actual boost pressure in many drive by wire gasoline engines) and fault codes had fairly consistent numbering.
![what is vcds what is vcds](https://www.ross-tech.com/vcds/tour/screens/gateway-coding.png)
These first appeared circa 2008 in cars like the 8T/8K Audi A4/A5. This thread is intended to address frequent questions from customers about control modules that use the "new" UDS/ ODX protocols. We can merge my stuff together with Jef's stuff to make a mad goulash with it: I made this draft post a while back but never "published it".