[OT] [NTLUG:Discuss] Hacking your car (was "C pretty....")

[Brian]

Jonathan--

You're talking about the "quick codes," or diagnostic codes.  There are
also high-speed serial pulses output from the ECM (electronic control
module) which codify various operating parameters, from manifold air
pressure to O2 concentrations in the exhaust.  Reading this serial
stream obviously involves some sort of decoder to read the pulses.

AFAIK, none of the auto manufacturers have made these protocols public,
which is why you spend several hundred dollars on "true" handheld car
diagnostic computers.  Every once in a while I do a web search in the
hopes someone has cracked the system, but haven't run across anything. 

  --Brian

Jonathan Miller wrote:
> 
> they actually do sell things that will allow you to "read out error
> codes." All that they do is count pulses. I had to trouble shoot a car I
> owned once and I connected an average every day LED to the proper pins on
> the little connector, fired the car up counted the pulses looked up the
> code in the reference manual.
> 
> --
> Jonathan                                     "Thinking corrupts the mind."
> 
> On Mon, 11 Oct 1999, Steve Baker wrote:
> 
> > Come to think of it, the "Check Engine" light on my minivan isn't too
> > far
> > from that!  Going to the Pontiac dealer to "read out the error codes"
> > isn't that different from core dump analysis with gdb.  They need to
> > open-source that sucker so I can save the $60 they charge to do it!
> 
> _______________________________________________
> http://ntlug.org/mailman/listinfo/discuss