Obd-ii

[rickp]

Does anyone know the bit rate, source address and target address for the data link? I'm trying to write a computer program to talk to my 96 G20. If anyone has any info at all on ISO 9141 or OBD-II for the G20 specifically, please respond.

[kris]

Originally posted by rickp
Does anyone know the bit rate, source address and target address for the data link? I'm trying to write a computer program to talk to my 96 G20. If anyone has any info at all on ISO 9141 or OBD-II for the G20 specifically, please respond.

I dont know, but I am interested in what you're doing.

[rickp]

Thank's for showing me some life under this thread. I already have the hardware to connect PC to 96 G20 diag link. The hardware layer is a RS232 to ISO9141 converter. Is is mainly changing the voltage levels of the bit stream at the PC to car voltage (12volts). Now I need software protocal info. This involves the bit rate and source (PC) and target (car ecu) addresses. Then I can write a Visual Basic program to run on the PC to comunicate to the car's ecu.

[sama]

knowing the address is not enough in my opinion. you need some kind of driver to control the hardware. i'm also very interested in this and was going to do my own obd-ii hacking this summer. i'm doing a similar project for philips now so let me look into it and I'll get back to you.

-sama

[rickp]

Thanks Sama. I'll be waiting for any info you can gather. This is my interpretation so far regarding the hardware layer. I think OBD-II has a few different hardware protocals. One of these include ISO9141 which you can generate from the standard COM port from a PC and level shifter I mentioned before. I do this at work for ECU's we develope for a certain car manufacturer. I believe my 96 G20 has this hardware protocal also. I've heard about other car makers using a PWM based hardware protocal. I can only guess this one would require a smarter external circuit.

[rickp]

Are there any Nissan folks out there that can provide info?

[unknown_g]

Hey ain't that a coincedence!!! I'm a nissan owner!! haha

Anyway i was doing a search on a search engine and came across your thread about the converter. I don't know if this might help you though but here you go:
http://www.ghg.net/dharrison/protoconv.htm