My 2002 Grand Voyager (3.3L) has just today started to give me the DTC of P0456 (Evaporative emission system leak (very small leak)). The van runs good, and the only thing I've done to it recently is that a few days ago I changed the air filter.

From what I've read this error is usually caused by a vacuum leak in the fuel system. So I've checked for:

A.) Loose vacuum hoses that go to the fuel system.
B.) Loose gas cap.
C.) Crack in the gas tank refill neck.

So far no luck. Also, what is strange is that I try to clear the "check engine light" with my handheld and my handheld gives me an error that says: "Clear attempt failed".

So a couple of questions:

1.) Can you guys think of anything else to check?
2.) When you guys use *your* handheld and try to clear a Check Engine Light that immediately comes back--does *your* handheld give the same error? Or, is it possible that it's a bad PCM?


Thanks,
Stan

Well, I disconnected the battery and this reset the DTC and the CE didn't turn back on. Also, my handheld still fails when trying to do a reset of the CE. (But the reset function works on all my other vehicles). I'm going to call up the manufacturer today to see what they say.


Concerning the P0456 code, I'll just wait and see what happens next with it. The van runs great with or without the CE light on.


Best Regards,
Stan

I just got the same code today on 2002 Grand Caravan 3.3L. I will try what you did to fix.

just a Head's up, I learned this...to clear code, have Key on Engine off. Do not have the engine running. that's how my van likes it I guess...yours might too.

I have this code as well - same vehicle, same year. Here is what I have learned through some research, trial and error.

P0456 is a small evaporative emissions leak. Since 1970 systems are designed to not vent gasoline fumes into the atmosphere. This code indicates a failure of this system that might pollute the atmosphere. The code is thrown after a test of the fuel system is run. The test puts a pressure in the system (positive pressure I guess, but not sure), and detects over time if the system is sealed by checking if the pressure is maintained. A code scanner such as the ScanGauge II can clear this code, but the key must be in the "accessory" position (engine not running). The test will rerun periodically (about every 2 days) and it will throw the code again, until you fix it. My friend says there are flags that a code scanner can read that say that the code has been cleared but the test has not yet been run again. State emissions tests will not pass a vehicle in this condition.

You've opened a two year old post. Best to open a new thread to get more exposure. A loose gas cap or bad cap seal will generate a P0456 code. Inspect vacuum lines especially the elbows leading to and from the leak detect pump underneath near the engine craddle the EVAP canister and purge valve. A shop will connect a smoke machine and look for smoke escaping from the system. http://www.obd-codes.com/p0456

I would not worry to much at this point. just make sure the cap is on tight and reset the light. If the light comes back after a few weeks then you will have to find out were it is leaking. I would start by takinig a close look at all the rubber lines coming from the tank to the motor for cracks. Very commen on these. If all check out good most likly cause is you evap leak detection pump haas fail.

Hello. I have a 2005 Chrysler Town and Country 3.3L and I recently got the P0456 code. I have checked the gas cap. It seems like it is on tight. Can anyone tell me how to clear the code and/or reset the light.

Try looking just below y the aircleaner box there is a schrader type valve in a hose that has 2 small pieces of hose on either side of it. These small hoses seem to split quite often on the bottom side of them,you have to feel it you cannot see it. My 01 had this code and replaced gas cap it was tight and then found these split hoses and haven't had a problem since. It gets really hot where they are so they get brittle and split