1997 F-Body ECM

[kur4o]

So far I have detailed much of the OBDII and Tside code.


I hope that this work will be of use to someone other than myself. Currently I am working on download. I have now digested steps up to the point where the tester has entered Mode $34. Last step is mode 36 to actually send something. I was surprised that all this isn't more common knowledge. I am now working out details such as which bytes are contained in the 16bit checksum of the download mode 36 commands. I hope to post details and a program to get a PCM reply of "Hello world!" soon.

Cheers, -Tom

I went through obd2 code real quick and it is a real mess at least on the 96. Later OS might get it a bit cleared.

As far as mode 36 block checksum is calculated on later vpw pcms it is really simple.
Sum all words after 6D 10 F0 36 ......data...... xxxx[last 2 bytes of checksum=block checksum] yy[vpw message checksum of whole message].
I couldn`t find it in the code to confirm but should be something like that.
The pcm might response with 72 and 77 message stating wrong checksum and longer than expected message.
73 or 78 or something else if the upload is successful.

Did you managed to find what modes are supported. I have a detailed info on most of them.