GM P3/P4 ECU scan tool's

[Terry]

steve ravet wrote:
>
> > I am currently trying to decode the ALDL streaming data that runs at 160
> > baud or 8192 baud depending on what model ECU is being used I have nearly
> > worked it out but still have a long way to go. Has anyone got or more to the
> > point willing to give information on this protocol . Is there any shareware
> > available?? If I am successful in writing a scan tool I would like to offer
> > it at no cost to all.
> 
> First, have a look in the archives.  Lots of good information in there,
> including the electrical encoding of the 160 baud stream.
> Unfortunately, the hard part isn't there, what the bits and bytes in the
> stream mean.  I've been in contact with a Delco engineer, according to
> him it varies by model/year/powertrain.


Here's a decent start;

http://www.isthq.com/~dan/aldl_tpi.htm

Good luck,

T.