Check engine light still on after tightening gas cap

[Lefty]

I have a 2004 Vibe with less than 76,000 miles on it. The check engine light came on the other day after I failed to tighten the gas cap. I've tightened the cap and filled the tank, but the light is still on. Will it eventually go off or do I have to pay a mechanic to turn it off? Is there any way I can turn it off myself?

[ehoff121]

You might want to go to an Auto Zone to have the code read for free to confirm that it was a loose gas cap. They can also reset the light.There are a couple of fuel system error codes that could mimic this problem, but could really be something in the fuel vapor recovery, e.g., a vacuum hose with a pinhole leak.

[djkeev]

Once an evaporative system problem is found, it will take several run cycles of the engine and the system doing a self check before it turns off the light.If it isn't off in a few days, get it checked out by pulling codes.Dave

[Lefty]

Does mileage have anything to do with how soon the light will go off? I'm retired and usually only drive about ten miles every other day. Thanks.

[djkeev]

Quote, originally posted by Lefty »Does mileage have anything to do with how soon the light will go off? I'm retired and usually only drive about ten miles every other day. Thanks. No, not usually, it is start cycles. The system does a pressure test on start up.Dave

[andy500]

I believe OBD II requirements is that the light will go out for a loose fuel cap after 3 ign cycles. Code will clear after 40.

[Lefty]

The check engine light was still on after eight trips, so I went to an AutoZone store and its device showed that the light probably was the result of a loose gas cap. They turned off the light and it hasn't reappeared, two trips later. Thanks for the help on this.

[silverbullet]

Interesting to note my local auto stores will no longer clear codes for liability reasons. Always have to do it the hard way, I hate fixing all the setting on the radio

[ehoff121]

Quote, originally posted by Lefty »... so I went to an AutoZone store and its device showed that the light probably was the result of a loose gas cap. If you can post the code here, there are forum members that can confirm the likelihood of it being correct.Watch for the light to come back on, though.

[Brandort3]

You could also check and see if it's the O2 sensors. If the codes say something about the first threshold, then that could be a possibility. The same thing happened to mine, and i had a buddy look at it and he said to check the sensors. http://i35.photobucket.com/alb...7.jpg

[vibedrivermatt]

hey even tho this issue has been solved I wonder if this could be fixed by resetting the cars ECU. To do this you would just need to remove the negative battery terminal, leave it off for ten minuets and then put it back. Then start the car and let it idle for another ten minuets or at least I think this is how its done? Somebody correct me if Im wrong. I do know that doing this couldnt hurt anything tho.

[LAVENDERCHICK]

I have an 05 vibe that I have had for 2 yrs. Its awesome except the check engine light has been on most of that time. When I have the messages read it always says faulty gas cap or 02 sensors. I have replaced the gas cap several times and the light will stay off for 2 couple hundred miles then pops back on. Soemtimes it will go off by itself after I fill gas tank to very top, but then it always come back on. Nothing else is wrong the car. Any ideas from anyone??? Is it just a bad read on some sensor somewhere???

[Salsa Guy]

What code are you getting with the CEL?

[LAVENDERCHICK]

I will go and get this read again for codes this week. And Ill get back to you. Thanks for replying.

[cerulean]

Quote, originally posted by LAVENDERCHICK »I have an 05 vibe that I have had for 2 yrs. Its awesome except the check engine light has been on most of that time. When I have the messages read it always says faulty gas cap or 02 sensors. I have replaced the gas cap several times and the light will stay off for 2 couple hundred miles then pops back on. Soemtimes it will go off by itself after I fill gas tank to very top, but then it always come back on. Nothing else is wrong the car. Any ideas from anyone??? Is it just a bad read on some sensor somewhere???Have you had the recall done for the ECM?This is very similar to how my 07 behaved before I got my ECM replaced as part of the recall.I knew the cap wasn't loose, so I replaced the O2 sensor. But the light would still come on (it would go away periodically). Somewhere on here, I found the troubleshooting guide for the code and traced it back to the ECM. Then I had to wait for my VIN to be added to the recall, since they were doing it in stages...Bob

Attached files P0031-P0038.pdf (46.5 KB)