Nother checksum question

[TBK]

Good response! I usually feel so guilty I start telling them where the body
is buried and confessing to every unsolved crime.

On the checksum side.....

If the checksum is not correct, the eprom won't work. The ECM will go into
backup mode. That's why the experimental byte is there. The eprom data can
be changed without changing the checksum until the modifications are
completed (during testing). Then a checksum is produced and stuffed into the
appropriate location adn the $AA is changed back to the ID number.

So the answer is: Get the checksum right or set the experimental byte or the
eprom will not work. The checksum is a simple (but to always reliable way)
to see if the eprom is not missing something or damaged. Of course if one
values is raised by one and another is lowered by one, the checksum will be
the same. But this is an unlikely failure.

TK


-----Original Message-----
From: bruce plecan <nacelp at bright.net>
To: diy_efi at efi332.eng.ohio-state.edu <diy_efi at efi332.eng.ohio-state.edu>
Date: Sunday, February 01, 1998 8:06 PM
Subject: Re: Nother checksum question


>Other than lossing a fault code, or needing to
>change a prom during early diagnostics, what downsides
>are there to not running checksums?.
>TIA Bruce     Worst answer given a cop by author,
>                    cop: I wanna see three things from ya
>                       driver's lic., registration, and deed to
>                       town X being your own personal
>                       race track
>                    me: would ya settle for two outta three
>