DIY_EFI Digest V2 #261

[Terry Martin]

Terry Martin wrote:
 
> What you are asking for is only available via a straight out power hack
> on the ECM/PCM/OBC depending on who you're talking to. The only other
> way I know of (other than inside information), is to pay an aftermarket
> supplier who has already acquired the bitmap, download the data, buy a
> custom burned chip with specific data altered, and run a verify with
> failure address flagged, and the guess the flags by running a test
> mill/PCM arrangement and determining what's what by sequentially
> altering the flags, ie EEPROM with programmer to modify data
> arrangement. This is not simple stuff. The hack takes more programming
> than the original program data, and requires custom built hardware. It's
> not feasible unless there's a pay-off.
> 
> Terry

There is one other way, which is to acquire a diagnostic scan tool such
as the Tech-I or more recently Tech-II at $4-5000, and scan the scanner,
so to speak. There are after market tools such as the AutoXray, which
cost about 1/10 as much, and are upgradeable to stay current with the
OBD-II stuff. 

In any event, it is possible to build an interface, and grab the ouptut
codes from the diag. scanner which shuts up everything else on the DL
and instructs the PCM (or whatever) to unload.
A program can be, (and has been), built which with modifications will
emulate the scanner and bag the data. There is also demo stuff which
will display the data flow, getting you a step closer to acquiring it.
The WIN95 O/S has a "accesibility" option which allows the com port to
interface with goofy crap. It also will disable a bunch of i/o
functions, and the data stream may have to be custom configured. BTW, I
haven't played with it much but WIN95 Hyperterminal can operate in a
simple data display mode, which may be a clue to the stream format.
 
You are still working with a code transfer, binary bus transfer, digital
communication, or data communications, (whatever), in hex, binary, or
BCD(Binary Coded Decimal), and a bitmapped array with programmed system
information flow, which requires a "fetch data" instruction, data load
by CPU into address register, and a command to read memory,  so if you
are a gear-head like me, you will likely require assistance in the way
of an electronics engineer. One helpful starting point is that it's
serial, one unhelpful starting point is that it has to be synch'd and
decoded. Prom level reads are simpler, however, they still require the
bitmap functions.

BTW, don't piss him/her off(your helpful pal) with dumb-head stuff, or
in other words, shut up & listen if you don't want to spend the rest of
your life pushing pistons. 

It's not really funny, but for some reason, seemingly realated to
program financing by grant at the institutionalized education program
level, ie Delco, the available info is limited to what will not result
in any sort of liability to the developer. At least Delco, (read dildo,
or fuck yourself) allows "leaks". Others are enigma's.

Terry