Modifying OBD-II systems

[Ken Kelly]

I put a 95 PCM with my 96 LT1 to avoid the problem. 

	I have been building an Editor for the 95 PCM, and as I go
I have been comparing the two Chips. The 95 & 96 PCM have
two Flash memories. They are usually labeled as the T side
and the E side. Most of my work so far is on the E side. The
E side is 512K in both years. The T side grew from 512K to
1Meg from 95 to 96. The following is what I have found
abvout the E side.
	I have found that the data tables in the two E side chips
are very similar, but offset a little from the 95 Chip. They
apparently have added a few 20 or 30 byte data sets in the
data area. SInce all of my investigation starts with the 95,
then looks for the same info in the 96, I don't know what
the new data they added is for. If you can break the
download barrier or socket your Flash chips, I have found
some of the tables. I know nothing about the OBD-II adders
like the After-Cat O2 sensors.

		Ken

Bill Shaw wrote:
> 
> And are these 'specialists' able to do much with them?  I know that GM
> won't give up the source (over 1000 pages I hear) even to the specialists.
> Faking out the sensors is MUCH more difficult with OBD-II, since each
> sensor reading is independantly verified by some other method.  Are these
> 'specialists' bypassing the OBD-II requirements making the vehicles
> non-compliant?  Or have they made the huge investment in reverse
> engineering the code? Any ideas here would be appreciated.
> 
> bs
> 
> >>  What do the guys with new cars do when
> >> they hot-rod them?  Stop participating in the program?
> >
> >Most so far have had to send them to folks that specialize in them.
> >Bruce