OBD_II You asked for experiences

[AL8001 at aol.com]

In a message dated 99-05-13 21:01:00 EDT, Wayne.MacDonald at zurich.com.au 
writes:

 With some
>research I found it used the OBD_II interface so I built an adapter to
>connect a laptop inline before the SAE-J1962 plug, I wrote a program to 
trace all the
>traffic then got the dealer to use the diagnostic tool to reset/read some of 
the sensors (He didn't know I had a PC connected)

I've thought of this as well for my 99 Chrysler 300M engine trans swap.  The 
program you wrote, is is just a serial port recorder?  I'm not a programmer 
and just have started into the word of OBD II stuff.

> I then spent the next couple of days at the standards
>office going through
>the data I had gathered, I found that the first thing the diag tool did was
> request that
>the ECU unlock, to this the ECU responds with a two byte seed value, the
>diag tool then responds
>with the correct key for this seed value and the ECU is unlocked.


For the American cars, the vehicle serial # is programed in to the ECU.  The 
ECU also has it's own (different) serial # printed on the outside.   I wonder 
if the serial # laters the code.

>I hope I have not been a bore.
>
>Wayne Macdonald.
>
>

Not a bore at all!    This is a great story on how to crack the codes!

Harold