Evap. System Leak, Help Please!

Hey Guys,

I have a 2006 Mitsubishi Lancer and CEL is on, I got the code checked and its showing P0456 (“Evaporative emission system very small leak”). They recommended that I replace the gas cap, but I already tried that without luck. I have heard that the tubes in the system go bad and need replacing. I know some are located behind the back wheel but I wanted to give the ones under the hood a visual inspection so I have some clue when I take it for a repair.

My trouble is that I don’t know what tubes I’m looking at! But I have some pictures, so at least we have that!

So the first one is zoomed out of the engine (obvious right?), just so you can see where everything is going. The hose I’m suspect of is the one that’s to the left of the motor oil cap, the one I’m holding in the second picture. If you can see it, theres a split running down for about 6" -10"

What I’d like to know is did I assume right that this is (at least one) of the hoses causing my trouble with the evap system?

and if it’s not, which ones should I be checking out?

Thanks a million guys, I hate going to the repair shop clueless :confused:

It may take some time before the light goes off. I think it took mine 3 or 4 days(different make). Clean the filler neck contact area and gasket in the cap with a paper towel just in case there is some debris causing the problem.
We also had a plymouth that had a pump to pressurize the system for the test, the pump failed causing the cel.

Thanks for the reply, but I replaced the gas cap weeks ago. I also disconnected the battery to reset the computer and turn the CEL off but it came back on after about 50 miles. Which is why I have no reason to think the problem is the gas cap, leading me to look for other ideas.

A logical step would be to fix the split hose first and see what happens.

That’s a great idea, but I don’t know how to do that. I’ve heard I can wrap some electrical tape around that but it’s clearly not a permanent fix. And unfortunately I don’t have the funds to pay for guess and check at the mechanics.

That looks like the split is in a covering that protects a hose, not a split in a hose itself. If so that is by design, not a defect.

The part you’re holding appears to be an electrical wiring harness, possibly for the A/C system.

You don’t know that you have a leak, do you? You have a fault code, but what makes you think you have a fuel vapor leak?

The car is not telling you that you have a leak, the car is telling you that the it THINKS you have a leak. If you take your temperature and the thermometer says 104* you could have a fever or the thermometer could be faulty.

The leak could also be not related to a hose. A vent valve could be not sealing properly, a purge control valve could be sticking open.

If you’re not mechanically inclined, the next step would be to find a shop with a capable scan tool and have the system tested and maybe smoke tested for leaks.

That stuff is the protective cover they slide over wiring. A smoke test would likely spot your leak.

The evap system tubing is in the back of the car, near the gas tank and gas filler hose. Most often the tubing is OK, but there are several “valves” in these systems that just get gunked up and don’t seal properly anymore. Since you are looking for the problem at the wrong end of the car I think you are going to have to take the car to a “pro” to figure out the solution.

Did you use an OEM gas-cap? I had the same problem with my 4runner. Went to my local parts store and bought a new gas-cap. Same problem. Then someone suggested the dealer. So I went to the dealer and bought a gas-cap…no more error code.

This code is sometimes caused by chronic overfilling of the gas tank. You must stop on the first click or you can eventually damage the system. Frequently this will eventually correct itself by simply not overfilling the gas tank anymore, stopping at the first click, but it can take a few weeks before everything dries out and begins to function normally again.

If you haven’t been adding gas after the first click, then the problem is elsewhere. You could have a stuck purge valve, a leaking hose or a crack in the evap canister. This takes time to hunt down.