Some of necessary goodies are available at mode 21 - should be independent on model



Table support with this site is very limited thus the picture.

 

That is going to scare about 99% of the people reading it here!

So what does this mean for the Evo X tuning world as CAN Mode 21 is revealed further?

 

I've never really been clear on this, so I'll ask: when you say 'Mode ##' in relation to CAN, are you just talking about ODBII Parameter ID's per the J1979 specification? And in this case, Mode 21 is some Mitsu-specific mode? Same for Mode 23, I'd assume?

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

Am I on the right track or am I crossing the streams? Sorry for the noob question, just trying to follow along

 

I was wondering the same thing, and got stuck at nearly the same place

 

As you can see at wikipedia there are mandatory modes for ISO9141 defined.

0x01. Show current data
0x02. Show freeze frame data
0x03. Show stored Diagnostic Trouble Codes
0x04. Clear Diagnostic Trouble Codes and stored values
0x05. Test results, oxygen sensor monitoring (non CAN only)
0x06. Test results, other component/system monitoring (Test results, oxygen sensor monitoring for CAN only)
0x07. Show pending Diagnostic Trouble Codes (detected during current or last driving cycle)
0x08. Control operation of on-board component/system
0x09. Request vehicle information
0x0A. Permanent DTC's (Cleared DTC's)

These are sometimes referred to as service (SID aka Service ID). You can pick the service mode that you need data from and ask for either PID (Parameter ID), TID (Test ID) or SSID (Subservice ID) if supported by service (e.g. service mode 0x04. "Clear Diagnostic Trouble Codes and stored values" does not have any further differentiation.

Automotive engineers did not find this as sufficient and developed the communication protocol further in ISO11898, ISO14229, ISO14230, ISO15031, ISO15765 and ISO27145. Therefore more services are available if ECU implements the specified standards.

Modes/services that are discussed in this forum so far are
0x21 Read Data By Local Identifier
0x23 Read Memory By Address

My post above explains what are available PIDs for service/mode 21 and what they return as the protocol says "the format and definition of the return values shall be vehicle manufacturer specific".

In order to have the necessary parameters logged, tephra found a way to get mode 23 working. My attempt was to find a way that would not need an ECU reprogramming. This is now mode 21. This mode does not require programming session thus should be available with simple diagnostic session and should not stop engine when running.

Together with my older thread, it should be enough to diagnose the vehicle status.

I hope I have explained it clearly

 

Like I said on chat

Mode21 is much like our MUT logging from CT9A, meaning what you can log is already set in stone...

My next tephraxmods will include a packed array which means that 1 request results in 15 or so items being returned.. This means about a 5x speed up in logging speed... it ALSO means that you get a snapshot in time - unlike the current method which has the different variables being updated in the background while the logger grabs the next variable...