Broadcast codes...

[Ludis Langens]

[I've also sent this via the coulomb address, but it doesn't seem
to have gotten through - sorry if it ends up being a duplicate.]

bruce plecan <nacelp at bright.net> wrote:
>My book goes up to '92 and I don't show your BBC, for a truck,  BE SURE you
>have the right calpak (V-8 part no
>16060836 last digit may be a 7),  they change calpaks from V-8 to V-6s, the
>little plug in chip beside the prom.
>BCC as far as I know it defines the emission package, vehicle, rear axle
>gearing etc., and the lastest revision
>of the prom for that application.  If ya e-mail me with the 4 letter code
>on the chip (BCC) of the ones ya got, I
>might be able to help.

The "little" plug in chip, sometimes called a Cal-Pak, is just a resistor pack.
It calibrates the fuel delivery for the limp-home backup mode.  It may also
calibrate a few minor items like the fuel pump run duration at key-on.  It
does _not_ contain data about the emissions package, gear ratios, and etc.
You can probably get by with the wrong Cal-Pak because very little, if any, of
it is used during normal operation.

The "big" plug in chip, sometimes called a Mem-Pak, is an EPROM.  It contains
all the emissions, ratio, and etc. data.  Plus, more timing and fuel tables
than you want to know.

Some ECMs (ie 2.5 L4) have the little chip built-in.  The "bigger" C3 ECMs that
I've seen have seperate sockets for the two chips.  Some ECMs (the '730 P4)
have both "chips" in a single carrier.

Kevin Vannorsdel <kv at us.ibm.com> wrote:
>I have some spare PROMS for this truck.  They are Broadcast ACSW.   Can someone
>enlighten me on what that means?
>Can I put my Blazer PROM in any 1227747 ECM or do I have to get one that
>matches the Broadcast ACSW?
>
>Is the Broadcast Code some sort of version number or what?

A 1227747 is a 1227747.  All you need to do is plug in the Cal-Pak and Mem-Pak
for your application.

GM appears to identify their [E]PROMs four ways:  1) An eight digit part
number which I presume can be used to order one.  2) Another eight digit
number, the last four digits of which are printed on the PROM.  The second
number tends to be a few counts beyond the first part number.  I think the
second number is equivalent to a casting code found on say a cylinder head.
3) A letter code like your ACSW.  I've heard of two letter codes and seen
plenty of three and four letter codes.  The codes seem to be incrementing
over time and skip a few letters like I and O.  4) An integer in the PROM.
This is reported via a scan tool.

Any of these four identify the specific calibration needed for your vehicle.

They stole your ECM?  Wow...

                   unsigned long BinToBCD(unsigned long i) {unsigned long t;
Ludis Langens         return i ? (t = BinToBCD(i >> 1), (t << 1) + (i & 1) + 
ludis at netcom.com                 (t + 858993459 >> 2 & 572662306) * 3) : 0;}