OBDII Port code

[william.buchanan]

Hi all

Has anyone out there got experience of communicating with the OBDII port on a vehicle?

I have seen a couple of things online but none seem to work. Also struggling to work out how to communicate with the cable via USB.

Any guidance appreciated….

 

[Skydiver]

It seems that you are looking for code, not guidance.

If you are truly looking for guidance, show us your code and tell us what specific issues you are running into. As I recall there is a couple of threads here and in DreamInCode where people were successfully talking to the scanner and most of their issues were with parsing the data that comes in. From your description above, it seems like you can't even get data from the device.

 

[william.buchanan]

It seems that you are looking for code, not guidance.

If you are truly looking for guidance, show us your code and tell us what specific issues you are running into. As I recall there is a couple of threads here and in DreamInCode where people were successfully talking to the scanner and most of their issues were with parsing the data that comes in. From your description above, it seems like you can't even get data from the device.

I don't really understand why you even bothered taking the time to write such an unhelpful and pointless response. If you're not going to offer help maybe just don't respond....

 

[Skydiver]

I am offering help if you are truly looking for guidance. Tell us what specific problem you are running into and show us your code that you wrote that is having the problem.

The reason why I made that distinction between asking for code vs. asking for guidance is because you are not the first to post a question in this forum or other coding forums where they say they are seeking "guidance" for something they are doing, and many try to help them out with frankly very helpful advice, and then they respond with "okay, can you just give me the code?", and people reply back to them saying that "you asked for guidance, not code." they leave in a huff saying something like "that was not helpful at all", or the post a short reply like "Nevermind, I found the code elsewhere."

 

[william.buchanan]

I am offering help if you are truly looking for guidance. Tell us what specific problem you are running into and show us your code that you wrote that is having the problem.

The reason why I made that distinction between asking for code vs. asking for guidance is because you are not the first to post a question in this forum or other coding forums where they say they are seeking "guidance" for something they are doing, and many try to help them out with frankly very helpful advice, but they leave in a huff saying something like "okay, can you just give me he code?", or the post a short reply like "Nevermind, I found the code elsewhere." So, you might as well just be upfront and indicate that you are looking for code instead of being coy and say that you are asking for "guidance".

Ok - fair enough

The story so far... I have spent a few weeks trawling the internet for code which will do this. I also have a USB/OBDII cable which is apparently for an Audi. So far all the code which I have copied from the internet doesn't work, so I am now wondering what I actually need to do to make it work.

The reason I say I am looking for guidance rather than code is because as you rightly point out there is code available to copy from the internet. But as I couldn't get it working I am now looking for guidance from someone who has done this before.

Do I need a special cable, or do I need to have some other code for the USB side of things, or do I need to configure the ports on my PC a certain way, etc, etc...

 

[Skydiver]

Get the specs for your cable. Ensure that it doesn't need a special driver to be installed on your machine to be able to talk to it.

If it can be just treated as a regular serial port, do a basic connection to it to see if you can see data coming in, even a simple error message coming from the device.

 

[william.buchanan]

Get the specs for your cable. Ensure that it doesn't need a special driver to be installed on your machine to be able to talk to it.

If it can be just treated as a regular serial port, do a basic connection to it to see if you can see data coming in, even a simple error message coming from the device.

The cable is a "USB KKL VAG-COM 409.1 Compatible Interface For VW/AUDI/SEAT/SKODA". I got the drivers from here:

Ross-Tech: VCDS: Downloads: Current Release and Manual

How do I do a basic connection test to see data? As I said - I literally saw nothing coming back using all the code samples so would be good to know if there is something I can use to check that the cable is even working....

 

[Skydiver]

How did the these go for you?

Start the VCDS program:​

• Click [Options] and select the correct communications port.​
• Use [Test] to confirm that the program can use the port and find the interface.​
• Then [Save].​

 

[william.buchanan]

How did the these go for you?

I just get an error - 'Ross-Tech USB Interface Not Found! USB Library Version: 03.02.07 Interface: Not Found!'

 

[william.buchanan]

Maybe I need to go right to the start here... I just bought the OBD cable from ebay (I assumed they were all standard). It didn't come with any drivers - I assume now it maybe should have?

Should I maybe look at getting another cable? Or do I need to get some kind of driver for it...? If so - what do I need?

Thanks

 

[Skydiver]

If the software there doesn't think it can find the device, and assuming that software is smart enough to do various retries, then it probably truly can't talk to the device. (Or the software can distinguish between authentic and knock-offs and refuses to recognize knockoffs.)

From what Google quickly turned up for me, the knockoff cable available on eBay require a much older version of "VCDS", but it was a lot of car talk jargon for me.

From the pictures I've seen for the knock-off Ross-Tech cables sold retail, they come with a small CD that has the drivers and software to talk to the cable. I thought that WalMart had it for around $9. The authentic cables supposedly start at about $350.

As a side question, does the cable even show up is the Device Manager as an unrecognized device?

 

[william.buchanan]

If the software there doesn't think it can find the device, and assuming that software is smart enough to do various retries, then it probably truly can't talk to the device. (Or the software can distinguish between authentic and knock-offs and refuses to recognize knockoffs.)

From what Google quickly turned up for me, the knockoff cable available on eBay require a much older version of "VCDS", but it was a lot of car talk jargon for me.

From the pictures I've seen for the knock-off Ross-Tech cables sold retail, they come with a small CD that has the drivers and software to talk to the cable. I thought that WalMart had it for around $9. The authentic cables supposedly start at about $350.

As a side question, does the cable even show up is the Device Manager as an unrecognized device?

Yes it's appearing in device manager. At one point I wondered if I would need to write some code to talk to it so I started looking into how to write a USB driver - again lots of examples online but none of them working. Another problem is that a lot of the code examples assume the OBD connection is using an old style serial COM port, so they just don't work.

I don't have an issue with buying the right hardware - the trouble I am having is finding clear and consistent advice on what the right hardware would be. There seems to be lots available ranging in price but how do I know any of them are going to work...

 

[Skydiver]

With device plugged in, is there a new COM part that shows up?

 

[william.buchanan]

With device plugged in, is there a new COM part that shows up?

No. It just shows a new USB device.

 

[Skydiver]

Does it show as a USB device with a yellow warning icon? Or as a normal icon? If it's a normal icon what is the device driver associated with it?