CAN Bus questions

You can get splitters that will fit on top of the OBD2 port, that way multiple devices can read from the bus simultaneously. I can't remember where I read it, but I'm pretty sure it's a token-ring network.

If you are looking to splice into the wires, you can get into it behind the regular OBD2 port under the steering wheel, but I wouldn't just start cutting things without some serious reading! Let us know how it goes.

[ame=http://en.wikipedia.org/wiki/CANbus]Controller area network - Wikipedia, the free encyclopedia[/ame]
On-board diagnostics - Wikipedia, the free encyclopedia

 

The CAN bus is just that; a "bus". This means electrically the same signals are present anywhere on it, and you can tap anywhere you like, just keep the tap length as short as possible. The CAN bus is terminated at each end with 120 ohm resistors to absorb the signal and prevent a standing wave reflection. These terminations are in the Battery ECU in the Rear, and the Engine ECM at the front. The DLC connector (OBD2) is in the middle.

Here is a simplified diagram:



The ScanGauge II uses a standard RJ-45 for it's connections. You should be able to tap the CAN bus right there at the Power Steering ECU and make up a cable. This will keep your wiring run short.

The Power Steering ECU is the big silver box right under the dash covering over the steering column.

If you don't have diagrams, let me know and I'll help you out.

 

I don't know if this will help anybody, but Jim Fell in England hacked into the CAN bus awhile back. His story was published in "Nuts and Volts" magazine, which is reprinted at: How to get 100mpg from your car - The IET . There were a few pictures in the original magazine article too, but I don't think they'd be helpful with the CAN bus. He somehow found out how to program a computer which could access the CAN bus and used that.