Got a P0456 engine code. Also leaking about 1/2 cup water overnight under the engine area.

B1342 is not an engine code. P0456 is. Follow the link for more info. P0456 Evaporative Emissions System Small leak detected

B1342 is a manufacturer specific code so need to know make and model and year.

typically means a faulty gas cap. Engine code P0456 can also mean their is a small leak in the EVAPVAPORATIVE hoses from tank to under hood.

Go to Oriley's and ask for a computer check and a readout

P0456 = "Evaporative emission (EVAP) control system leak detected (very small leak)."

P0456....Evaporative Emission Control System Leak Detected (very small leak)

P0440....Evaporative Emission Control System

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.

most auto stores such as auto zone / advanced auto scan vehicles for free check ur local area but first check ur gas cap- for tight and on correctly loose gas cap no 1 check engine code

P0456: Evaporative Emission System Leak Detected (small leak)

Using a Multimeter, check the Evaporative Emission (EVAP) Canister Purge Regulator Valve N80 terminals 1 and 2 for resistance. You should get 22.0 to 30.0 Ohms. If not, replace the canister. If you do, you have other problems.

P0456 is a code set when there is a very small leak (theres very small leak, small leak and a couple of others, your code indicates the smallest level of leaking). This can be caused by a vacuum line that is cracked or otherwise leaking on the evaporative (EVAP) system. It could even be from a gas cap that is not sealing properly, though typically a gas cap leak tends to set code P0441. Just the same, and since it is the cheaper way to go, start by replacing the gas cap and see if that clears the code and any check engine light you may have.

Once you replace the gas cap you may need to disconnect the battery for a couple minutes to reset everything if you dont have access to a scanner that can do it.

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