CAN Bus PID's

[J_Rough]

Hey, i'm a first year student at university and ive been given a project in which i need to monitor what a car is doing through it's CAN Bus. Nothing fancy, just "Front passengers window going down" or "Ignition key turned". Ive bought a CAN Bus to RS232 adaptor, plugged it into my Skoda Fabia (im british) and tried monitoring what happens when i do certain things using Hyper terminal on my lap top. Nothing came up, and when something did come up it was enormous quantities of data. Ive put some research in online and read other posts on this site but still can get it to work. Has anyone got any suggestions??

[Chris@HPTuners]

http://en.wikipedia.org/wiki/OBD-II_PIDs

generally on modern cars there is a lot of data flying around on the CAN bus as the modules all send information to each other and it's all in a proprietary format. Typically most hardware filters (or has the ability to filter) out just the received traffic to the tool.

Typically you'll be transmitting your data with ID 0x7DF or 0x7E0 when talking to the ECM and receiving data with ID 0x7E8.

There's lot sof info in the wiki link above regarding SAE PIDs and packet formats.

Good luck with the project!

Chris...

[J_Rough]

Thanks a lot chris, thats great. Do you know if it would be possible to use an inductive clamp to monitor the CAN Bus? Im assuming it will be hard but is there a product for it or has anyone done it before?

[Chris@HPTuners]

i doubt it.