Project - what's possible with Can?

Hello there,
I believe this is my first post, although I've been browsing this forum as a guest quite often for about 5 months.
Since I've already done a lot of research on this topic, but I'm unfortunately stuck and can't make any progress on my own, I'm hoping...
I appreciate your support and am, of course, happy to provide you with information.

To me:
- I am a student of business informatics, and therefore have knowledge in the field of IT.
- I've been programming in Java as a hobby for several years (which is why I'm currently working on my new project).

First of all, regarding the project I want to do:
- Monitoring and control of certain vehicle functions such as the radio, turn signals, lights, speedometer, etc., using a self-written program based on Java.
- Later, voice control for some functions will be added.

Purchased hardware:
- Peak-Can Bus
- OBDII connector
- a few D-Sub9 connectors to connect the OBDII connector to the CAN interface.

Following the instructions on Peak's website and the OBDII website that you are probably familiar with, I connected the correct points together (although I'm not sure if I even need the ground connections).

Subject of the experiment:
My test subject was a brand new VW Golf 5 belonging to a friend. I located the OBDII port, connected with my CAN interface, and tried to read data with CANEASY, the CAN hacker, and the pre-installed Java example program from PEAK, initially at a baud rate of 500k, after turning on the ignition (and also in all other ignition positions). When that didn't work, I also tried reading data with all the other standard values. Unfortunately, every possible attempt has been unsuccessful.
Since I don't own a car with a CAN bus system, I can't simply connect to the entertainment/comfort bus.

According to the workshop, it should be possible to access the CAN data from the car's OBDII port (as has been incorrectly stated and argued in many posts that it shouldn't be possible), because this diagnostic port is also connected to the CAN gateway. The mechanics I spoke with hadn't heard of wake-up modes before.

I hope there's someone here, either a car electrician or someone else with relevant qualifications, who can help me.

I've already created display devices for the speedometer, tachometer, and fuel gauge using Java. Instead of using sliders, the displays should be controlled by receiving CAN messages, preserving the original functionality. But without detailed CAN messages, I have no basis on which to program .

I hope with your help to find out what's going on with Can.

Regards,


Mattias

Hello.

Okay... nice Java application. I like it (visually, at least).
I wouldn't use the color red for Can L. Red is positive and can lead to confusion .

Okay, now let's get to your questions...

I don't think a regular automotive mechanic would be familiar enough with CAN bus technology to say definitively whether or not a 'wake-up' function is implemented. I think that's going too far.
On the other hand, the OBD port does not contain any direct data. A query is possible here.

Speak:

You're sending a...
- Identifier 100 (which means queries)
- Data: 10 80 00 20 00 00 00 00 (which means, give me the speed).

and you get the answer:
- Identifier 200 (which means 'response')
- Data: 10 85 45 65 f5 00 00 00 (these values represent the speed and will naturally change).

Keyword: SAE J1979


I'm not sure if you have a more specific goal in mind, because what you're planning already exists in abundance, in the form of ready-made hardware and software. But tell me more.
Sure, here's the translation:

'lg' is a German abbreviation that stands for 'liebe Grüße,' which translates to 'best regards' or 'warm greetings' in English.

Hi p.ostrich,

Thank you for the quick response.
I gladly accept any praise for the design, as I am not a graphic designer :p.

I am aware that the SAE J1979 standard allows you to initiate OBDII queries. However, as far as I know, these queries are limited and do not contain all the information that can be obtained from the CAN bus. If I were only interested in the speedometer, tachometer, and fuel level, then using the OBDII PIDs would be the best approach. However, the speed, tachometer, and fuel level information should only represent the beginning of what I ultimately want to achieve. These are intended to serve as test objects for communication with the CAN bus.
I know that there are already a few programs that can accomplish all of this.

But as a programmer, it doesn't matter to me whether something already exists or not; what matters is whether I can program it myself, and above all, gain my own experience. Ultimately, I'm not lacking in ideas, but rather in the information needed to put them into action.

For example, I would like to use a Java program to control the windows, the radio, and, if possible, also the lights.

My last project, for example, was a program that could be controlled using voice commands.
Have you ever imagined talking to your car? Yeah, I know, it sounds a bit like 'Night Rider'...

As I said, my project is called: what everything is possible with Can!

But focus on CAN, not OBDII.

-> It needs to be clarified whether, and especially if so, how one can access the CAN bus from the OBDII connector, and what information can be obtained from it (as far as I know, this has not really been discussed throughout the entire forum). In principle, it should be possible to access any conceivable information from the diagnostic CAN bus, since it is directly connected to the CAN gateway, where all buses converge.

I hope for more participants! And that all questions can be answered.

'What I'm missing here in the forum are detailed instructions. If I can ultimately get help here, I'm of course willing to write such instructions, as long as they are not legally prohibited.' I think many people would be interested in this!

Regards,


Mattias

Thank you for the objection (drawing error), which has now, for some reason, disappeared after I modified my main post.
-> Drawing has been modified; soldering was performed correctly.
Mattias

Please, after I noticed that you had structured it correctly, I deleted my post .

Without further ado, you won't be able to access the infotainment and powertrain CAN buses from the diagnostic CAN. These are separate systems. The buses converge in the gateway. If you want to access the different buses, you would need to make multiple connections, specifically one at the CAN_Powertrain and one at the CAN_Infotainment. I am not aware of any way to directly access the various buses from the OBD interface.

I haven't worked with the drive CAN myself. However, you can use the diagnostic CAN to, for example, receive commands from the multifunction steering wheel (louder/quieter, next/previous, etc.) or send commands yourself. Similarly, the radio data is transmitted to the onboard computer.

The diagnostic CAN bus does indeed connect to the gateway, but not all signals from the CAN bus for the powertrain, comfort systems, infotainment, etc., are combined on this bus.

Hello,
Thank you for the quick response!
On the diagnostic CAN bus, you can, for example, intercept commands from the multifunction steering wheel (louder/quieter, next/previous, etc.) or send commands yourself. Similarly, the radio data goes to the onboard computer.

What am I doing wrong when I'm connected to the OBDII port? I was already hoping to receive just one message? ^^
The following document also accesses the data via the diagnostic bus.
http://www.13ter.info/obd2.pdf

Is there a way to access one of the buses without breaking anything?
(Unfortunately, I don't have access to my own car.)

Does anyone have any pictures of how to tap into a cable?

Regards,


Mattias

Hello Mattias,

For the cable connecting the 9-pin D-connector to the 16-pin OBD2 connector, only CAN-low and CAN-high are connected. Power is supplied via the USB connector.
The GND (ground) connection doesn't need to be connected either. (So, only 2 cables are needed.)
I don't know how this change will affect your attempts, and unfortunately, I'm not familiar with the Golf.
Good luck with your endeavors!

uiuiu
That's a tricky thing. So, as you mentioned yourself, it's an OBD2 'DIAGNOSE' interface. You can access a lot of data there, including engine data, etc. However, the queries are often manufacturer-specific.
Just check with a VAG Com or any other diagnostic tool. However, they vary from manufacturer to manufacturer.

To simply read data, you need to connect directly to the gateway, specifically the motor CAN bus or similar. The easiest way is to insert needles into the connectors at the back. This will give you a huge amount of data. You'll just need to decipher it, unless you have any other information.

That's why I mentioned the SAE J1979 standard, because the information is standardized and can be accessed in every OBD-2 vehicle.
Sure, here's the translation:

'lg' is a German abbreviation that stands for 'liebe Grüße,' which translates to 'best regards' or 'warm greetings' in English.

I don't have a VW, I have a Volvo. I need to replicate a VW instrument cluster for the interface of my retrofit hands-free system, as well as the VW steering wheel buttons from the MFL (Multi-Function Leather steering wheel).

Can someone tell me which IDs the MFL is transmitting on, and which bytes contain the key information?

I don't usually like to revive old threads, but I would also like to try replicating this. Is the Java code accessible, or can you send it to me?
Sure, here's the translation:

'lg' is a German abbreviation that stands for 'liebe Grüße,' which translates to 'best regards' or 'warm greetings' in English.

I'm also joining

I'm in .