hey, i have a 92 30b tbi. i prefer working on my car myself, dont like to give the car to mechanics. basically when im driving the "service engine soon" light will light up out of no where. then it will just turn off. it keeps on doing this and has been doing this for a while. what can be causing the problem, and or how do i get the light to stay off always? let me know.

Dozer80464@aol.com

 

Did you run it for codes? Gotta see what's tripping it 1st before you can go to the next step.

 

what does that mean? and how do i do it?

 

https://www.thirdgen.org/newdesign/faq/thirdgen.shtml
Scroll almost all the way down--it's under misc.-it'll tell you how to retrieve the codes-and what it's for.

 

I have had the problem of it coming on when the gas cap is not tightened well enough on about three gm cars now so thats the first thing i check. Just a heads up if you didn't know

 

Vacuum leak can do it too.

 

My light used to come on all the time. All I did was replace the O2 sensor and it went right off, not to mention a jump in gas mileage and performance!

 

My light used to do that too. I finally broke down and took it to a mechanic for a computer check and I needed a new EGR valve. So now $200 later I get about 5 more miles per gallon, I actually pass emissions without any help, and no more service engine light.

 

Just run the codes and it'll tell you what's wrong!

 

hey do you run the codes? what are terminals.. etc?

 

YOu HAVE NOTHING TO WORRY ABOUT!

This is a common problem with my car.. after driving it for over like 20 min. on the highway it will come on for no reason, it usally does... I checked codes.. I get a code but I dunno what hte heck it means.. haha

But so far ive heard it happens a lot in Camaros.. where the light just comes on cause : you got a new tranny, New engine, New Parts.. sometiems the computer dont recodnize it.. or just dosent like it!

 

THE ALDL connector is what you need to find first. It's under the dash, drivers side, near the center console. If the cover is still there it will say "Assembly Line Diagnostic Link" on it.

THE CONNECTOR


-----------------------
| 1 2 3 4 5 6 |
| 7 8 9 10 11 12 |
-----------------------


DISPLAYING THE TROUBLE CODES
Run a wire/hairpin from, with the ignition off from Pin 5 to Pin 6, then turning the ignition to the on position without starting the engine will flash the "Service Engine Soon" light in the following sequence: flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause flash, pause, flash-flash, long pause Following this "12" code repeating three times will come any trouble codes stored, flashing each of them three times. If you do not see the "12" flash three times, your diagnostic circuit is defective.
Some vehicles will display stored trouble codes, then "12" again, followed by energizing "most system controlled relays." The fuel pump relay will not energize. The idle air control valve will fully extend to enable checking minimum idle speed.