06 mustang gt. driving to work this morning my check engine light came on, when i got to work i hooked up my tuner and a P0442 code came up. Under the description it said Evaporative emission system leak detected. small leak .040".
What does this excatly mean?

 

Hey man, this happened to me, too. When did you put gas in the tank? You should check to make sure your gas cap is securely fitted and tightened. If it was loose, not tight enough or off-thread and you retighten it, the check engine light should go out after a small period of time. I cleared my own with my DS Trinity. I know, tightening the gas cap all the way seems like a no-brainer...but sometimes if we're in a hurry or whatever, we won't tighten it the 3 clicks like the manual says and we don't even realize it.

 

Thanks, i could very well be my gas cap i've been having some issues with it.
I just retightened it and cleared the code,so we will see.

 

If its not, there are a few issues with EVAP solenoids and vents. This can be data logged by SCT PID. Plenty of threads around on it. Does it only happen at certain times? Is the engine sluggish or shutting off at all?

 

No it has never happened before and no loss of power at all. It was fine driving home yesterday and going to work this morning.Thanks for the response.

 

It's probably the gas cap. I had to replace mine.

 

Us 2010 guys don't have that problem, there ain't no gas cap

 

I had the code and it was operator error. Crooked gas cap. LOL

 

I just got this code again. Looks like another gas cap bit the dust. I think it's been several years since I replaced it.

 

I am still running the original and vintage '05 gas cap