Evap. Leak


I drive a 2003 Jeep Liberty Sport, with the 3.7 liter V6. It has roughly 97,000 miles on it.

In the year or so that I’ve owned it, the jeep’s check engine light has come on several times. Every time I’ve had it checked, it’s the same issue - a small evap leak, code P0442. Typically, they’ll reset the computer, and I’ll drive it for two or three months and eventually, the code will come up again.

Oftentimes, I’m told it could be caused by a loose gas cap. I’m aware of that and I try to make sure it’s nice and tight every time I fill up. I’ve also looked at it, and there are no visible cracks or holes in the cap itself. But, the problem still occurs.

So, I’m wondering if anybody out there with some experience working on jeeps can offer me some advice on what this could be. What else, besides a loose gas cap, could cause an intermittent small evap leak?


“DaimlerChrysler has determined that some 2003 Jeep Liberty vehicles may be in violation of Federal and/or California emission standards.”

Was this vehicle targeted and has this vehicle had the fuel system Recall performed ?

Some of the vehicles need to have the fuel pump assembly replaced.


Certainly check out any recalls & such as CSA mentioned.

Other than that small evap leaks aren’t uncommon - but are uncommonly hard to find. The first thing to do is not just make sure the gas cap is tight, but also inspect the filler neck for any kind of issue - a small dent or scratch or some kind of crud stuck on it. Also inspect the gasket for the gas cap. New gas caps aren’t that expensive. You can just get a new one.

If nothing about the gas cap is found to be a problem then the easiest way to find the small leaks is probably to have a shop perform a “smoke test.”