Any information out there on CAN bus commands?

**davepl** · 06-30-2006, 07:19 PM

I have a dream. And here it is:

I'd like to get a CAN <-> USB adapter, hook it into my laptop, and be able to send and receive commands on the CAN bus. I'd like to be able to do things like "if I see two door unlock commands in a 3 second window, lower to convertible top".

I've spent the afternoon on Google, and really didn't find much. There are lots of code scanners out there, but I guess what I really need is:

1) A CAN-USB interface that can receive and SEND commands to my E46 M3
2) A document that describes the known (standard) CAN bus automotive commands

Surely someone has been down this route before. Could someone jumptstart me by pointing me in the right direction?

Many thanks!
- Dave

**Rickertsen2** · 07-02-2006, 01:02 PM

I think the CAN protocol only specifies HOW to say something on the bus, not WHAT to say. The OBDII stuff is standardized but that certianly doesn't include things like sunroofs ect.

Your best bet would be to get a CAN interface and sniff the bus. Its going to take some reverse engineering but is very dooable.

**yargon** · 07-13-2006, 11:13 AM

As it's said, Canbus messages are not standard. Each manufacturer has its own set of messages, and they are confidential.

So, the best thing you can do is sniff the bus and log and learn.

**dwhite** · 07-17-2006, 04:30 PM

Or you could hit this site and pick up our stuff (http://www.gsdtelematics.com/page008.html). We have a device that does all protocols and has an API to make programming the vehicle a snap. Check out the ViveScense software layer link. You can check out the News and Events sections to see some videos we have done with some customers.

Our products are a little bit more expensive ($299 for wired and $599 for wireless) but we connect to all netowrks and can connect to multiple networks at once. That means if you drive a car that has multiple networks (ISO, CAN, and J1850 PWM) all on the same truck, our software can talk to them all at the same time. And, you get the ViveScense software layer for free when buying the hardware.

As for CAN specific messages we have reverse engineering tools we use as well. The nice thing is we have car specific codes in a construct called a vehicle adapter. We have a number for cars we have worked with. What kind of car do you have?

David White
GSD Telematics