What is that plug all about?

[gdouaire]

What is that plug all about? It looks stock and is located under the dash, right beside the ash tray.

See arrow below:

 

[tc1959]

http://en.wikipedia.org/wiki/ALDL
http://www.obd-codes.com/faq/read-gm-2- ... s-free.php

 

[gdouaire]

Never thought OBD made it on these carburated g-bodys. Interesting! Thanks.

 

[wrenchbend1]

This plug is refferred to as the aldl connector in 1996 they became standard and is what is in every car today. PRIOR to 1996 every manufacterer had thier own connector for on board diagnostics. I belive it is on every car that has a check engine light and an oxygen sensor . Prior to 87 carburated units had thier version , Electronic Fuel injection was in its infancy. Does your car have a check engine light ? If the check engine light comes on one can get the computer to "Flash" code by putting a jumper between terminals "B" and "A" (in the 12 pin diagram )and turn the key to the on position. the check engine light will begin a series of flashes and pauses which translates to the code currently affecting the system. Terminal A is a ground and b need to be grounded to get the computer to self test. Thanks to TC1959 for the diagram !

 

[seawolf18]

When you ground the terminals and turn the key to on. It will flash code 12 three times, pause then give you a stored trouble code. If there are no codes stored, it will continuously flash code 12. The computer system was pretty primitive compared to the OBDII systems used now days.