2001 Dodge Caravan did not pass emissions due to evaporative hose leak - trouble PO442 (small leak) and 456 (large leak). It was recommended to change gas cap. Did so and the light went out. I took van back to emissions maybe two weeks later, and just as the rep was checking it, the engine ligtEngine light stays on so gas cap was replaced. Light went out, Have changed gas cap, light went out. Returned to emissions, light came on again. Any suggestions?

code p0442 refers to evaporative emission (EVAP) system--small leak detected====causes hose connection/s---intake leak--EVAP canister---EVAP canister purge valve
it also refers to evaporative emission system --large leak detected (fuel cap loose/ off)===causes---mechanical fault--hose connection/s--EVAP pressure sensor.

EVAP emission system (small leak detected during vent closed test 1) error;
This is usually a broken line somewhere. Sometimes it's the connector on the EVAP canister itself (large plastic canister with two ports and hoses coming out of it). Unfortunately, when I smoke test these, it's usually bad news (the large hose running back to the fuel tank from the EVAP canister has a pinhole leak in it). Holes as small as a human hair in diameter will set this code. Check the large vacuum connections on top of the canister to the throttle body. Check the canister itself, if it's cracked, it must be replaced. If all that tests out, have the system smoke-tested for leaks. Replace any hose that fails the test. Clear the condition and turn off the MIL. Drive the car for twenty minutes to see if it comes back.

P0305....Cylinder 5 Misfire Detected

P0442....Evaporative Emission Control System Leak Detected (small leak)

P0455....Evaporative Emission Control System Leak Detected (gross leak)

this code# po442 is avery small leak in the evaporative emission control system. First check that the gas cap is on tight, past the clicking sound. this uaually solves the problem. if you need more help get back to me and we'll go from there. Please rate my fix as i strive to be the best Thanks Ray

Hose cracked,loose,different switches,sensors,gas cap, any number of things. It is a system, on to itself and not easy to repair.

PO442 is the data trouble code for (evaporative emission control system leak detected "small leak") it means that the OBD-II system has detected a small vacuum leak in the evaporative control system.

You will need to find the vacuum leak in the evaporative control system, check for cracked or broken vacuum lines and hoses, especially the vacuum hoses and lines around the evaporative (Evap) canister and the (Evap) solenoid. Also check the gas cap seal for damage.

Vacuum hoses and lines should be checked very well for any cracks or breaks, because they usually hide under the vacuum line or hose.

This can be because the Gas cap is not holding the pressure. I would start there first.

po442 is evap emission control system leak (small) 1 of the lines for emissions is leaking. po455 is-- emission control system leak (large). turn off light with code scanner after it is fixed.

If you have an EVAP leak, you will get the following codes:

1. P0442 evap emission control system leak (small).
2. P0455 evap emission control system leak (large).

If these codes come up, you need to trace the leak. The most common place for the systems to leak besides the gas cap is at the service port under the hood, the hoses at the purge solenoid, and the hoses around the fuel tank. Check all your EVAP hoses from under the hood , all the way back to the gas tank. You can repair a split hose easily. Buy some 14.5mm EVAP hose at the auto parts store. Just cut the split or cracked section out and attach the new hose.
I can only say that u must fix the code issue and light to pass state emission test, if u reset the light they will know, the system will tell the tester that the system is not ready, this will cause a fail.

Is your gas cap tight? check it, these codes indicate a large leak in the fuel evaporative emission recovery system at the gas tank