So, at least the 2006+ S2000 outputs the Steering Angle (degrees -720 to 720) and Brake Line Pressure (0 to ~9 MPa) via the 'OBD2' port using CAN. Can I read this via an OBD2 PID? I am able to read this and a whole lot more by using HDS.

I guess I need to sniff the CAN messages with HDS running.

 

Interesting.. I guess the brake line pressure is read from a sensor in the ABS module?

Can you elaborate on the difference between a regular OBD2 port "reader" vs. a CAN bus reader? My understanding is that the CAN bus is one protocol used in the OBD2 implementation. Do you know what most regular Obd2 bluetooth readers read? Is it the CAN bus or a different protocol? This sounds like a very interesting and handy feature to have as I'd love to log brake pressure. I remember gernby mentioning about logging data via the CAN bus to generate a "dyno," but this sounds much more useful to me. If you can point me in the right direction to get more info this might be something worth playing with and writing some code for.

 

Sounds useful to me too! Is brake line pressure something that FlashPro can read and log?

 

That's a good question.. I remember gernby commenting how the flashpro datalogging is slower than a regular can bus reader (his early iteration of his "dyno" I believed used datalogs from FP), so I wonder if the resolution of the flashpro would even be good enough for real time datalogging..

From some quick reading it seems like it's commonplace for many sensors to not be exposed/available to regular obd2 readers (I still don't know what BUS "obd2 readers" read), but the CAN bus has much higher resolution and all available sensors (it's what the ecu sees realtime). It seems like some of the AIM datalogging units have the ability to read/log from the CAN bus, which is pretty darn cool. Anyone with more info on this subject care to shine some light on it? I might have to ask gernby to chime in on this thread since he obviously has some experience w/ it..

 

Certainly looks doable. AIM lists support for logging on the can bus for the 2006-2011 civic. Might just be worth buying an AIM.

http://www.aim-sportline.com/downloa...11_102_eng.pdf

 

Wow that's awesome that 06+ has brake pressure sensor and steering! These are two things on my short list to add!

 

Unfortunately, for the S2000, it just logs basic OBD information

 

Gernby would be a great person to check in with. I believe he did some work sniffing the CAN chatter and using pattern recognition to figure out which bytes correlate with RPM, Speed, etc. for his road dyno. The beauty of CAN is that all the sensor data is sent to every module all the time and because the Steering Angle and Brake Pressure are critical to the VSA and TCS systems, I bet it operates on the high speed bus (500kbps).

It's on my to do list to get a CAN sniffer and sit there datalogging everything while keeping everything constant but the SA and BP. It should be fairly straightforward to isolate the bytes that correlate to these two items. Then it's just a matter of having something that automatically parses these bytes and injects it into whatever else you want.

 

You're right. OBD2 can be of many protocol types like fast/slow init ISO, KWP2000, JAEsomething-or-the-other, CAN 11 bit, CAN 29 bit etc.

All the data is being broadcast all the time like an AM/FM radio. We just need to tune in to the right frequency.