Sniffer Can Bus

[cusna]

Hello all,
yo day I have buy CANdoISO to be able to read the CAN communication to the electric power steering, FIAT Punto
I would, once successful, to analyze data, build a "CAN emulator" to run the electric power steering without it being connected to the body of the computer 'cars.
Opinions, help?
Thank you

[Wilksey]

Unless you can find a download for the I guess, power steering module for the car and the packets it uses to communicate I don't think you will be in much luck.
This kind of information seems to be sold within the automotive realm and is a bit like magic tricks, no one will tell you anything!  Of course you may find someone who has the information but will probably cost you a small fortune for the privilege!

What I would suggest is to hook the thing back onto the car or find another car (can be in a scrap heap for all it matters as long as there is a battery in it) and "sniff" the can-bus between the ECU and power steering control module (or an intermediary control system if applicable), capture the packets and try and decode and make something from that!

Hope this helps?

[cusna]

...
What I would suggest is to hook the thing back onto the car or find another car (can be in a scrap heap for all it matters as long as there is a battery in it) and "sniff" the can-bus between the ECU and power steering control module (or an intermediary control system if applicable), capture the packets and try and decode and make something from that!

Hope this helps?

is exactly what I want to do, however, know that there are already
CAN emulator precisely for this function, that communicate to the electronics of the electronic power steering, is that if the motor is switched on, both what is the speed, so as to harden, steering (that is, make it less sensitive) at higher speeds.
It will be hard but I want to try

[Tupperware]

Is this just for fun or are you trying to achieve something in the car?

I would start by identifying the CAN IDs of the messages broadcast by each relevant unit (ABS, EPS, BCM?) using your sniffer.  You can probably use the diagnostic services (0x19) to find out which signals the EPS is expecting, assuming the DTC numbers are available.  Then try simulating messages until the DTC goes away.  Probably best to log a section of messages from the car and just replay a single message at a time as they messages may include rolling counters and checksums which won't be valid with static data.

[dennis78]

I think basic info from ecu: speed, rpm,... with big patience you can decode. I never analyse in detail can bus in cars, but I think most ECU's every x ms send broadcast message with basic info to another modules (dashboard, servo,...) Maybe these basic info are enough for activate servo. Anyway, you need car, sniffer and much free time... You want to make equipment for testing (problematic FIAT electrical servo?

[cusna]

My final target it's  to build an simulator to work on laboratory without ECU and find the CAN-BUS messages to
activate the steering electric power in this case.
The first test connecting the CANdoISO to the steering control board without ECU ,
I capture this code ID=382  data=0xA8 and then ID=702 data=0x00 0x66
I searching one ECU to connect to check the data !

[Tupperware]

Not sure I follow your statement "without ECU"!  What was sending the messages? ;-)

As a hint I would expect at least a status message and a steering angle message to be broadcast by the ECU periodically.  If you turn the steering column does the content of one of the messages change?  It might be in an error state at the moment which would lead to static data.  At least you know which messages to sniff in the car when the system is working.

There is probably a couple of CAN IDs allocated for Rx of functional/physical diagnostic messages and one for Tx of responses.

I would guess that the ECU is looking for at least vehicle speed and engine speed/status, plus maybe some other messages to store odometer, date/time when a fault occurs (depends on FIATs requirements).

Getting hold of the technical service information for FIAT would be really useful as that should give a list of all DTCs and give you some more hints about which messages the EPS is looking for.  Not sure if these are available for FIAT, but I have seen them for VW, Ford, Peugeot etc.

[Elmer]

If indeed what you want is to build an ECU simulator, have a look on the (very simple) ECU simulator implementation done at http://smartdcgenerator.blogspot.no/. If I understand your motivation correctly, he built his pretty much for the same purpose.
There is however a lot of CAN sniffing to do before you get anywhere near implementing such a simulator, Not knowing or considering the hardware you have at hand, I'd suggest a CAN-enabled uC coupled to a CAN tranciever (get the automotive grade, MCP2551 comes to my mind, newer probably exist), and a Logic Analyzer on the uC side of the tranciever to monitor and map messages. Just my $0.02.

Cheers

[LabVIEWguru]

A number of years ago I built a system that tested functions on a dashboard for a vehicle. I used PCAN developer and a CAN to USB interface. The system ran in LabVIEW and did what you are after. There was also a PCAN set of routines for Visual BASIC or VISUAL C++, I don't remember which. (I don't have these)

I don't have the application anymore but if you are interested I could post a zipped up file of PCAN Developer. It ran under LabVIEW 6 or 7, so it's pretty old. Search for it and if you can't find something recent I'll post this.

It's going to take some work because the internal command set was a secret - so if you wanted to turn on the headlights, you had to capture all the data and correlate the command with the headlight switch being pulled.

Now that I think about it, I think there is a CAN package included as an option with LabVIEW. All you have to do is learn a new language!

Good Luck.

LabVIEWguru


Wow! Here you go - link is attached - they sure have cone a long way and support a lot of languages.

[LabVIEWguru]

http://www.fischl.de/usbtin/

USB - to - CAN and it is very nice - very professional

Board, micro and crystal <15 Euros
He also has links to other USB / CAN projects.