What exactly does that code mean exactly. It is a P0442. Evap sytem leak detected. Small leak it says in brackets. Just wondering what can cause this code ?

 

its a vague code, just basically means there is a leak in the evap system somewhere, could range anywhere from vent valve is not sealing, purge valve is not sealing, gas cap not tight or seal is leaking slightly, fuel fill hose leaking, evap line connections leaking. or worse there is a crack in a evap line or fuel tank somewhere. most common is gas cap not sealing, then vent valve, then purge, then connections.

 

I just checked my gas cap. I filled up last night on my way home. And my gas cap when i checked it right now did seem to tighten down a tiny bit more. Like maybe a clock or two and it felt like it tightened a tad more. Maybe that would cause the code ?

Also... I just replaced both my vent valve in the tank and my purge valve in the intake mani both about this time last year. The vent valve in the tank was an updated part. As well i had to buy a new hanress cause the new part doesnt connect to the stock pigtail. The new harness adapter cost me as much as the other two valves combined. Lol

 

its very possible that the cap wasn't tight enough. I would clean the gasket and filler neck. I personally also use a tiny bit of dielectric grease on the gasket to help it seal better and not get super dry. dirt on the gasket can also cause the code to set.

Also may not be a bad idea to get a new gm cap depending on the condition of the gasket.

 

Also check your fuel lines in the back, there is silver heat tape with cloth underneath that rots the lines out. It's right before the back wheel where they bent to go up and to the tank, cut the shielding off with a razor and see if the lines are swollen like a marshmallow. If so, rockauto sells a complete kit that's easy to assemble.

 

Exactly what I was going to suggest. That area is a common leak point; both the fuel supply and vapor lines rust out and leak. As mentioned, you can replace both lines with an aftermarket set with an anti-rust coating from Rock Auto or Lines-to-go. I found that Lines-to-go was cheaper because they offered free shipping.

If you do find that your lines are rusted through, reference this thread to report the issue to NHTSA so that they can pursue a recall/reimbursement for owners.

 

Definitely easier than what my buddy did. Mine went bad and I got them through rock auto. Time consuming but easy, just match up the dots and don't tighten anything until it's all assembled and ran properly. He went to chevy and bought the complete line and then tried jamming it under the car and bent them all to hell ������

 

Gotcha, bad for him but good for you. Previous owner of mine destroyed it and bubble gummed it together and sold it to me. Found all sorts of messed up stuff on mine. I got the short end of that deal lol