ALDL Serial Data cheat sheet?
Thread Starter
Heel & Toe
Joined: Apr 2005
Posts: 20
Likes: 0
ALDL Serial Data cheat sheet?
Hi again, all...
While my scanner does "some" fancy stuff like O2 sensor reading, open/closed loop, etc, some of the diagnostics I'm trying to do refer to Tech 1 features such as manual control over the fuel pump relay, reading of high/low-res ignition triggers, etc.
Has anyone backwards engineered (or just plain found data for) the ALDL serial protocol to an extent where it would be possible to manually explore these things? I know WinALDL will do the generic stuff, but not sure if it'll do the rest.
I combed the FAQ thread pretty thoroughly, and didn't see mention of this there, and Google likewise didn't turn up anything relevant in the last hour or so. Figured I'd ask the experts, heh.
Thanks!
- Pat
PS: Before anyone asks, since people seem to assume ignorance online, yes, I am fairly familiar with embedded systems and software, and yes, I was a certified mechanic for several years, so while I'm not exactly an expert, I'm not exactly a clueless n00b either. ;-)
While my scanner does "some" fancy stuff like O2 sensor reading, open/closed loop, etc, some of the diagnostics I'm trying to do refer to Tech 1 features such as manual control over the fuel pump relay, reading of high/low-res ignition triggers, etc.
Has anyone backwards engineered (or just plain found data for) the ALDL serial protocol to an extent where it would be possible to manually explore these things? I know WinALDL will do the generic stuff, but not sure if it'll do the rest.
I combed the FAQ thread pretty thoroughly, and didn't see mention of this there, and Google likewise didn't turn up anything relevant in the last hour or so. Figured I'd ask the experts, heh.
Thanks!
- Pat
PS: Before anyone asks, since people seem to assume ignorance online, yes, I am fairly familiar with embedded systems and software, and yes, I was a certified mechanic for several years, so while I'm not exactly an expert, I'm not exactly a clueless n00b either. ;-)
Burning Brakes
Joined: May 1999
Posts: 760
Likes: 1
From: Greenwich, CT
Originally Posted by rannoch
Has anyone backwards engineered (or just plain found data for) the ALDL serial protocol to an extent where it would be possible to manually explore these things?
10-15 years AFAIK.
Publicly available OBD1 ALDL definition files are shown here (xx.ads files):
http://tunerpro.markmansur.com/
However in '94 GM went to parallel processors, and the ALDL information
became more difficlut to extract - I have not seen a public program for
the later PCMs.
OBD2 data definitions are public information (EPA specs), but require special
chips and programming to read from a modern GM datastream - good luck
with that.
HTH
Thread Starter
Heel & Toe
Joined: Apr 2005
Posts: 20
Likes: 0
D'oh! Sorry, it's for a 1992... I could've sworn I put that in. 
Though I might move it to a 94 ECM this winter, we'll see.
TunerPro looks appealing, as it includes things like block learn... and the "required donation" version (somehow different from "buying"?)includes logging so that's 80% of what I'm looking for. Not sure if it includes any visibility into timing data, etc. But it'd sure be nice if I could find something that would output control info as well, such as forcing the fuel relay on, etc.
Though I might move it to a 94 ECM this winter, we'll see.
TunerPro looks appealing, as it includes things like block learn... and the "required donation" version (somehow different from "buying"?)includes logging so that's 80% of what I'm looking for. Not sure if it includes any visibility into timing data, etc. But it'd sure be nice if I could find something that would output control info as well, such as forcing the fuel relay on, etc.
