Check Engine Light

[coachkwj]

I have a 1999 Pathfinder that my son uses for College. It just came up for emissions test in Illinois. They use the plug-in computer method.
The check engine light comes on intermittently and the code is for the evap system. I erased it at Autozone but it came back on in a few days. I want to get it to pass the emissions test once more so my son can use it for his final year but I do not want to spend any big dollars on repairs. Any suggestions on how to get it to pass the computer test?
Thanks.

[Towncivilian]

Please give the exact code that the scanner tells you (will look something like P0505).

[Innovazn]

Considering its an evap code youre coming up with (not even looking at the code and off the top of my head mind you) and considering it comes on and off, it leads me to ASSUME that it would be more then likely the gas cap.

A) your son is not tightening the gas cap till it clicks,
B) Simply put, the cap is just plain old and needs replacement (i believe it was like $18 from dealer)

I have a evap leak and first thing i did was get that changed. Unfortuantly it was not the problem for me so i am looking at a $115.00 evap test to find cause of problem.... From there i will no... (apparantly worst case is 3k)

[coachkwj]

The cap is definitely being tightened correctly but you might be on to something that it is just old.
Not too expensive to try that. I wrote down the code but can't find where I put it! I will try to find it or just go to Auto Zone and re-check it.

[coachkwj]

Please give the exact code that the scanner tells you (will look something like P0505).

Code is P0440. Evap Emission System.

[Towncivilian]

I second replacing the gas cap with a new OEM to start with.