What are BCCs, mask ids

[Shannen Durphey]

RDwoo10 at aol.com wrote:
> 
> This leads me to a question.  I don't completely understand the definitions
> of all the terms.  I have found that there is a lot of information on your
> web site regarding CPU's & applications etc. but nothing that tells you the
> big picture.  Is there such a document?  I think what would pull it all
> together for me is something like:
> 
> GM made a CPU the part number is XXXXXX7730.  
: )  Too many x's.  GM part nos are typically 7 or 8 digits long,
though there are still some 6 digit numbers from the early days...

>for this CPU there is a Mask
> ID, it is imbedded in the code & it means YYYYYYY. 
It's an identifier.

> there is also a Scan, ID,
Different identifier.

>  the scan ID tells you that this CPU has ZZZZZZZ. 
No, starting to drift here.

 the XXXX CPU can use a
> YYYY Mask, ID but not a ZZZZaaaa Mask ID. 
Depends on the interpretation of can use.

 this is the piece that I am
> missing here.
> 
Scan id and BCC are for technicians in the shops, records at GM.  The
scan id is displayed by a scantool.  It is a number in the prom
designed to be used as a reference in finding the latest calibrations
or pinpointing calibrations that have been replaced due to
"concerns."  The scan ID is 4 digits long, and different calibrations
can use the same one.  Using it effectively requires an idea of the
year of the car, along with engine size, ecm number, and/or a couple
of other small details.

BCC, Broadcast code, is a four letter/four number code used to
identify a specific calibration.  By using a book or list, the bcc
will reveal the year, engine size, ecm#, trans type, and other info. 
I know of no instance where 2 different calibrations have exactly the
same BCC.

Mask id is a number within the data in the prom.  It less specifically
identifies the general calibration family.  There are sometimes
variations on a single mask id, some of which are major, some of which
are not as major.  

Knowing only the BCC can reveal the scan id and ecm number.  Knowing
only the scan id can reveal a few different ecm's and BCC's.  Knowing
only the mask id can reveal several different ecm's and multiple bcc's
for that ecm. 
Shannen

> Is there such a thing?
> 
> Thanks as always.
>  BW
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