Re: What model ECM is this ?

[Team ZR1 <teamzr1@teamzr1.com>]

Shannen, I talked to Ron Zimmer and he says that what he calls the"Body computer" is needed
to have the Diacom
work. I'll have to call him again but that sounded like he CCM he was talking about.
He has worked on other Morrson designed racecars and saw the same thing.

My interest on this was solely so that I could use the Diacom Plus while I was at practice
at these Open Road Races so I could tune to the conditions of the public road / location we
are racing on.
Since the Snakeskinner can not be driven on public roads ( car never had a VIN number ) at
this time I have to start the race with almost zero test time.

Shorting the two pins does not buy me anything since the car has no normal ign system key.
To comply with IMSA, SCCA, etc the main key turns all power on and off thus the ECM gets
dumped each time the car is turned off.

John

Shannen Durphey wrote:

> LOL!!!  I can't believe I missed this.  Here I'm thinking it's
> contained within the ECM! John, the CCM is the "Central Control
> Module".  It's a separate, external box who's job is to operate the
> digital instrument cluster, decode the vats signal, illuminate seat
> belt, hatch ajar, and other warning lights; operate door locks and the
> security system, control interior lighting, and a whole bunch more.
> It has a dedicated terminal in the ALDL (pin G) as well as two serial
> data lines to communicate with the ecm, abs/tcs, and the heat and ac
> controller.  I can scan this huge list of accessory functions that it
> controls, if you're interested.  The CCM is also able to display
> trouble codes generated by other control modules on the system, such
> as the ECM and HVAC controller, through the instrument cluster.  It
> coodinates data exchange between these modules, like a traffic cop.
> However, the CCM does not inhibit the scan tool data exchange.  As a
> method of double checking, I'm looking over the diagnostic charts for
> "no aldl data" right now, and the ccm is not a culprit in any of
> them.  In addition, there's evidence that the ECM cannot tell that the
> CCM is not communicating with it.  The lack of an ECM code for loss of
> serial data is a big clue in my book.
>
> In a stock configuration, the serial data line is connected to pin M
> in the ALDL, directly under A and B, so it looks like a triangle of
> terminals in the right hand side, with the "ears" of the ALDL
> connector positioned on the bottom.  I would make sure mine was the
> same way, if I were in your shoes.  Jumpering A and B should cause the
> check engine light to flash trouble codes.  Installing a stock ZR1
> prom should allow Diacom communications.  Wouldn't it be nice if the
> solution is that simple?
>
> What stock vettes blink code twelve with just the key on?  Usually it
> takes a jumper in the ALDL.
> Shannen
> PS, you've brough an interesting problem to the list.  Even the quiet
> guys seem to be jumping to help.