#135913 - phonymike - Fri Jul 27, 2007 11:44 am
I've searched the entire internet (from top to bottom,) and found little information on programming OBD2, but I think I found enough. turns out OBD2 is a standard, but there are many protocols running on this connector. first info I found out there were three protocols, ISO, CAN, and VPW. no biggie, it turns out my car uses ISO. then it turns out there's at least three ISO protocols, 9141, 9141-2, and 14230-4. which one does my car use? possibly the later 2. now the spec sheets on these protocols can be purchased from the iso or sae websites, for like $60-$150 or some shit. I also found an open source OBD2 program which I just don't want to decipher.
so, anyone have precise info on the ISO 9141-2 protocol? I'm not talking PIDs, just the communication protocol. or if anyone has any interest in such code let me know. there are commercial chips available (ELM?) that do RS232 but I feel it's unneccessary cause with 2 transistors, 4 resistors, and a little gba programming, I have the hardware interface ready to go. I plan to only code what I need for my car, it will be ISO 9141-2, no other protocol. it should work in most hondas with OBD2. the best website I found to tell what your car has is this place. I have yet to verify what my car has due to lack of protocol info but I'll see what I can piece together. any ISO 9141-2 info is appreciated!
so, anyone have precise info on the ISO 9141-2 protocol? I'm not talking PIDs, just the communication protocol. or if anyone has any interest in such code let me know. there are commercial chips available (ELM?) that do RS232 but I feel it's unneccessary cause with 2 transistors, 4 resistors, and a little gba programming, I have the hardware interface ready to go. I plan to only code what I need for my car, it will be ISO 9141-2, no other protocol. it should work in most hondas with OBD2. the best website I found to tell what your car has is this place. I have yet to verify what my car has due to lack of protocol info but I'll see what I can piece together. any ISO 9141-2 info is appreciated!