Service engine soon -- codes

Hi everybody,
I'm hoping that someone here might be able to help. I have a 97 GMC Jimmy (S series) and I've got to get looked at because of the service
engine soon light.
What I'm wondering, is there some place on the Internet (or elsewhere), where one can obtain the data structures and protocols used by GMC? Better yet would be something that could simply be installed and used, but being a programmer I figured that if I could at least get my hands on the specs for this stuff I'd probably be able to write the program myself.
Can one find these things anywhere?
Andy
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Andrew Falanga wrote:

I would wager that is an ODB-II system. Most auto parts stores will pull the codes for you for no charge. Or pick up a code reader for yourself. Or search the net with your favorite search engine and you'll likely get lots of hits on the subject.
--
Roger

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Just get the codes read for FREE at your nearest Autozone, Advance Auto, Checkers, Pep Boys or NAPA.
Doc
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"Doc" wrote:

Thanks to both of those who answered. This will be much easier than I thought.
Andy
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Check out www.bb-elec.com they make many protocol converters and also have a OBD II Diagnostic scanner for vehicles '96 and up. They also provide some info on the protocols used by GM, Ford, Chrysler. They don't get into detail but they list the Standards (i.e. GM uses SAE J1850 VPW.) I believe the Society of Automotive Engineers writes the standard protocols, at least in the US.

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