Check engine light comes and goes

A few months ago my check engine light came on. Scanned it and it was secondary air injection failure. Took it to a shop and told me it was fine so I cleared the light. Didnt come back. About a month ago, the light came on again. Checked it and it was a misfire. Had the car checked out and again it was fine. Cleared the light. I figured no big deal, both of those were probably just random instances.

About two weeks ago, light came on again. Next day I started it up to go have it scanned and the light was gone. Sure its a relief its gone, but I'd like to at least know what code is was throwing. Last week, same thing again. Light came on, and about an hour later it turned off. Again yesterday. Light came on and turned off within 24 hours.

Maybe I've misunderstood in the past, but isnt the car supposed to hold codes UNTIL they are cleared? I dont understand whats resetting the codes. I'm not having any battery problems, so I dont get what could be clearing them.

I'm starting the think its the computer going out on me. The car runs normal before, during, and after the light comes on, nothing changes. No problems.


Any suggestions? Is there a way to check the computer to see if its going bad?

2000 Lumina, 3.1 engine. 145k

here's a basic description of how it goes. PCM/ECM sees a fault, sometimes it will turn on the light, sometimes the fault has to happen a certain number of times before light comes on. wether light comes on or not, it is supposed to retain code as a "history" code until enough drive cycles have occurred without fault happening again. in short, it is supposed to retain the code for some time, but have no idea why yours is not. could be PCM going bad, could be other electrical issues. personally have not seen this before, but a qualified tech should check it out...might be worth the diag fee to know there is nothnig currently wrong.

A few months ago my check engine light came on.told me it was fine Scanned it and it was secondary air injection failure. Took it to a shop and so I cleared the light. Didnt come back. About a month ago, the light came on again. Checked it and it was a misfire. Had the car checked out and again it was fine. Cleared the light. I figured no big deal, both of those were probably just random instances.

About two weeks ago, light came on again. Next day I started it up to go have it scanned and the light was gone. Sure its a relief its gone, but I'd like to at least know what code is was throwing. Last week, same thing again. Light came on, and about an hour later it turned off. Again yesterday. Light came on and turned off within 24 hours.

Maybe I've misunderstood in the past, but isnt the car supposed to hold codes UNTIL they are cleared? I dont understand whats resetting the codes. I'm not having any battery problems, so I dont get what could be clearing them.

I'm starting the think its the computer going out on me. The car runs normal before, during, and after the light comes on, nothing changes. No problems.


Any suggestions? Is there a way to check the computer to see if its going bad?

2000 Lumina, 3.1 engine. 145k
it's a Lumina, get used to it. worst car i've ever owned...

it's a Lumina, get used to it. worst car i've ever owned...

Worst car you've owned? I feel bad for you and your other cars because the Lumina is a pretty reliable car if you take care of it.

Worst car you've owned? I feel bad for you and your other cars because the Lumina is a pretty reliable car if you take care of it.
absooooofrikinlutley
i love my lumina
if you are cheap,and dont wanna maintain your car

my friend,you get what you deserve:evillol:

Our 1993 Lumina also does that. I cleaned the IAC & it went out for along time. Today the wife said it was back on, then called me to say it was off again. I have never tried to pull codes. This Lumina belonged to a family member & has 237,000 miles without any major problems. So those that believe a Lumina is a piece of crap 237,000 miles speaks for itself. My wife commutes with it everyday 90 miles round trip. This light deal has been going on for 4 years I know of. But runs great light on or off. Still gets 20-25 MPG.

I had the same problems that came and went. It ended up being a faulty gas cap. Cheap fix.

Now...can anybody tell me how to get my big fat $%#&@! hands around the back of the engine to remove the three $%#^@&! plugs? :banghead:

I know, I know. I'll start a thread for that. :iceslolan