Re: Disguised scan tool

[Shannen Durphey <shannen@grolen.com>]

That's a good question.  Some cars have a jumper in the ALDL cover
which connects the ECM serial line to the BCM serial line in a loop. 
I think the 88? Toronado is like this.  When the cover is removed and
the scan tool is connected, scan tool communications are actually with
the BCM.  But BCM info is pretty scarce, and I haven't found anything
concrete yet.

 I think I'll pick up one of these BCMs if I find it cheaply enough. 
Still haven't heard about the optional crt available in these cars,
and what drives it.
Shannen
> 
> That's an interesting idea.  Would the BCM from a particular car only
> understand the ECM from the same one?
> 
> If nothing else the BCM code would contain the info for converting ECM
> values to real world values.
> 
> --steve
> 
> Shannen Durphey wrote:
> >
> > I just realized that GM is making scan tools that the average joe can
> > get cheap.  They happen to look like the BCM in upscale cars.  Most of
> > these read the data stream off the same serial data line as the scan
> > tool, and most give access to test functions that aftermarket scan
> > tools won't.  tTo make a real trick unit, get the wiring for the Olds
> > with the CRT, and find out if there's a special video driver there
> > that can be ordered separately.  That car displayed several data
> > parameters at once.  After that, you'd need to find a small tv screen
> > and be all set.  Fred B, you've played with this one.  Any chance for
> > the idea?
> > Shannen
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> --
> Steve Ravet
> steve.ravet@arm.com
> Advanced Risc Machines, Inc.
> www.arm.com
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