2001 Chrysler Town and Country LXI 3.8 with the check engine light on. Codes are p0420, p0442, p0455, and p0456 are these codes all sepperate problems or could they all be connected? What would be your suggestion? Where should I start to fix these? The van runs fine I have put a new gas cap on the van. Any help would be greatly appreciated. Thanks.

yes. the rubber gaskets do wear out. on most vehicles the gas cap
should be tightened 'til it"clicks". you probably can't tell from the
"appearance" but if you tighten 'til it clicks then drive for awshile and still
get the same code, the next step is a NEW gas cap/

What code ? P0442 or P0456 or p0455
DTC EVAP P0442 P0455 P0456
EVAP Leaks P0442 and P0455

Wells EVAP Training with Sgt Tech P0440 P0441 P0442 etc

you can look up these codes on actron.com or google that code

P0456 is a small vacuum leak - see if you can trace down the vac lines for inspection according to the diagram that's on the sticker under the hood (it should be near the end of the hood prop on the covering over the radiator). I just took a picture of my 2002 Chrysler Town & Country but to get it small enough to upload you can't read the detail.

P1684 is an easily trigerred code that is from a diagnostic reader or battery issue - not 100% sure of it's cause but it does not trip the engine light.

http://www.obd-codes.com/

P0700: EATX Controller DTC present
P1684: Battery was desconnected
P0442: EVAP leak monitor medium (.040). Leak detected.
P0455: EVAP leak monitor large. Leak detected.
P0456: EVAP leak monitor small (.020). Leak detected.

I suggest check the lines and flow it down to the ldp (leak detection pump) that is just behind the steering gear under the van It has a wire connector and 2 large EVAP hoses. look for any split or crack then follow the lines back to the tank. Even a small crack is a leak.

Hope helped with this. Remember rated this help. Good luck.

First of all, these codes are what are called "Powertrain Trouble Codes' (that's what the "P" means P=Powertrain). TCM Request (Transmission Control Module = TCM). The request was to turn on the 'Check Engine" light.
P0720 - output speed sensor circuit malfunction
P0715 - Input speed sensor (turbin speed) circuit malfunction
P0442 - Evaporative Emission System Leak (Small Leak)
P0455 - Evaporative Emission System Leak (Large Leak)
Check fuel filler cap problems - for Evap Emiss leaks
Replace the pulse generators & have the trans fluid replaced/flushed.
The Main Catalyst System Efficiency Bank 1 Is P0420, not P0442
If you had P0420 code, the catalytic converter is shot... and that's an expensive component.

hello po442 ,po455,po456 is leak detected possible, check the gas cap , basicaly you have a leak that is larger than 0.020' and smaller than 0.040' in the gas evaporative system use your nose to find this one thanks

P0442, P0455 AND P0456 are all evaporative leak monitor test failures (small, medium and large leaks). These codes appear anytime the integrity of the air space above the fuel or the lines to/from the vapor canister or purge valve. If there is no damage to the canister, check the lines that run under the van from the fuel tank and canister to the purge valve (under the hood). Also, check to make sure that the hoses are not split or disconnected where they connect to the purge valve. The P1684 is abit more confusing. This is not a valid DTC for your vehicle. It's possible the scanner the shop you went to is an OTC scanner that is reporting a false code. It's also possible they wrote it down incorrectly. The closest thing that makes any sense is a P1486 which would indicate a pinched hose in the same monitor system as the other 3 codes. Best of luck!

P0442--Evap Emission Sys. leak detected small leak
P0455--Evap Emission sys. leak detected gross leak
P0456--Evap Emission Sys. leak detected very small leak