Ford Emission Code

2005 Ford Taurus - 77K miles - 6 Cyl-OHV 3.0L engine. CEL on - Code read as follow:

“P0456 Evap Emission Control System Leak very small”

Does anybody know what this could be ??

It could be a bad or loose gas cap, but then again it could be several other things.

The fuel tank vent system (which includes the gas cap) consists of two or three runs of tubing between the gas tank and the carbon canister and the intake manifold…Sometimes the canister is visible under the hood and sometimes not…Various check valves and purge valves enter into it…It’s really not an issue unless you must pass an emissions test…

It’s really not an issue unless you must pass an emissions test…

Or you want to be able to know when you get another CEL.

Been There, Done That. Look Closely At The Sealing Surface Of The Gas Cap Sealing Ring And The Part Of The Filler Neck On Which It Seats.

Wipe / clean these parts well and make sure everything is quite clean and smooth. I have found that a liberal application of WD-40 spray on both the cap and the neck helps keep my small evap leak code(s) from triggering.

Next step would be to try a new gas cap before launching into major a diagnosis.


Joseph, I Agree. That Light Should Be Off For The Reason You Stated. Most Of Us Admonish People For Driving Around With Their “Check Engine Light” Illuminated.