Can Bus Information

**_MARIO_** · 04-18-2006, 06:40 AM

Hi,

I am interested in interfacing to the CAN BUS, do you have any information on how I could do this?. I would like to be able to read can messages generated by the devices on the car, sort of a CAN BUS sniffer?.

Is there any posibility I could get the frame format interchanged between the different control units (I dont know if this is the correct way to call this)? and the format used?

I would like to now about any interesting information regarding CAN BUS, VW can bus implementation and hardware/software related to this.

Thanks.

**Rickertsen2** · 04-19-2006, 03:06 PM

The elmscan can sniff CAN as well as communicate on it. I know microchip also makes a line of PIC microcontrollers with CAN support.

**_MARIO_** · 04-19-2006, 04:13 PM

Hi,

I have searched through scantool.net but not found any device that states it can read CANBUS, all the devices are ODB2 compliant, I guess I am a bit confused between ODB and CAN BUS.

CANBUS is the link layer ODB runs on?.

Originally Posted by Rickertsen2

The elmscan can sniff CAN as well as communicate on it. I know microchip also makes a line of PIC microcontrollers with CAN support.

**Maximus** · 04-22-2006, 05:02 PM

You need a canbus adapter of some sort.

http://www.canusb.com/

I use: http://www.peak-system.com/db/gb/pcanusb_gb.html
and with that you have some drivers so that you can write your own programs
and a basic logging software.

If it's a BMW then a much simpler adapter will do:
http://www.reslers.de/IBUS/index.htm

/M

**_MARIO_** · 04-23-2006, 03:55 PM

Hi Maximus,

That hardware & software looks great. What about the price?. I am looking to play arround with VW Golf 2006 CAN BUS.

Thanks.

Originally Posted by Maximus

You need a canbus adapter of some sort.

http://www.canusb.com/

I use: http://www.peak-system.com/db/gb/pcanusb_gb.html
and with that you have some drivers so that you can write your own programs and a basic logging software.

**pastypyro** · 04-23-2006, 03:59 PM

Does this software have the CAN database for VW in it? This would be what each hex CAN message actually means. I'm pretty sure that's confidential, at least it is with other car manufacturers.

**Maximus** · 04-23-2006, 07:07 PM

Nope, it doesn't have any information what so ever about any of the data you recieve.
You'll have to go by trial and error.

I think the CanUSB is around $100-150 and the Peak-Can ~$300-350.

/M

**pastypyro** · 04-23-2006, 09:46 PM

Trial and error is going to be pretty close to useless most likely, as there are TONS of messages broadcast every 20 or so milliseconds. One the vehicle I'm working on EVERYTHING is on CAN. Granted some things on the low speed network might be possible to pick up and play with, it probably won't be anything useful.

What specifically do you want to do with your setup? I've been using CAN with some pricey National Instruments hardware to build a datalogger that can log virtually anything going on in the vehicle and control some things via the PC. But, this requires the manufacturer's message database.

**_MARIO_** · 04-24-2006, 07:09 AM

Hi,

I just want to play arround, maybe write something on FIS screen, mainly now what is going arround my car BUS.

Is there anywhere I could find the database for the car messages?, maybe not oficially but an unoficial one. What is the correct name for this database, just to make a couple of searches.

Thanks.

Originally Posted by pastypyro

Trial and error is going to be pretty close to useless most likely, as there are TONS of messages broadcast every 20 or so milliseconds. One the vehicle I'm working on EVERYTHING is on CAN. Granted some things on the low speed network might be possible to pick up and play with, it probably won't be anything useful.

What specifically do you want to do with your setup? I've been using CAN with some pricey National Instruments hardware to build a datalogger that can log virtually anything going on in the vehicle and control some things via the PC. But, this requires the manufacturer's message database.

**Maximus** · 04-25-2006, 05:29 PM

Originally Posted by pastypyro

Trial and error is going to be pretty close to useless most likely, as there are TONS of messages broadcast every 20 or so milliseconds. One the vehicle I'm working on EVERYTHING is on CAN. Granted some things on the low speed network might be possible to pick up and play with, it probably won't be anything useful.

Well, if you say so...

On my car (SAAB 9-5) the network is devided into P(owertrain) and I(nstrument), the I-Bus is using low speed and most data are repeated (polled) once per second (if they change the change is instant).

Initially I used a National Instruments-PCMCIA/CAN2 but the included software is very basic so I wrote a small VB app so I could log what I wanted to file.
Then I've used the PCAN adapter to do some more logging and testing and today (actually) I used a Softing CanCard2 with Vector CANanalyzer software in order to verify bit timing registry settings and error frames.

As for "pretty close to useless" and "might be possible to pick up and play with, it probably won't be anything useful"...

I can read (among other things):
Which doors are open, fuel level, lights, indicators, pedals, engine temp, RPM, speed, position of gear-lever, current gear (automatic, but it tells me rev. neutral, 1st to 5th and two stages of lock-up), inside temperature, selected memory for the powered seats (great for controling profiles in the carputer), reostat setting, incoming light(both the one that controls the climate control and the one that controls the lighting of the instruments), and more...

I can present text on the on-board-computer:

All of this is done _without_ any information database what so ever, just a whole lot of logging.

The only thing I wanted to read/control that I can't is the cruise control, I had an idea that you would set it where you wanted and when the navigation system detected a speed camera it would decrease the speed to the speed limit and once you've past the camera it would resume "normal" speed.
But since it's hard wired to the ECU, I can't control that, unless I get a relay board of course

/M